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Medvedev RY, Afolabi SO, Turner DGP, Glukhov AV. Mechanisms of stretch-induced electro-anatomical remodeling and atrial arrhythmogenesis. J Mol Cell Cardiol 2024; 193:11-24. [PMID: 38797242 PMCID: PMC11260238 DOI: 10.1016/j.yjmcc.2024.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 05/29/2024]
Abstract
Atrial fibrillation (AF) is the most common cardiac rhythm disorder, often occurring in the setting of atrial distension and elevated myocardialstretch. While various mechano-electrochemical signal transduction pathways have been linked to AF development and progression, the underlying molecular mechanisms remain poorly understood, hampering AF therapies. In this review, we describe different aspects of stretch-induced electro-anatomical remodeling as seen in animal models and in patients with AF. Specifically, we focus on cellular and molecular mechanisms that are responsible for mechano-electrochemical signal transduction and the development of ectopic beats triggering AF from pulmonary veins, the most common source of paroxysmal AF. Furthermore, we describe structural changes caused by stretch occurring before and shortly after the onset of AF as well as during AF progression, contributing to longstanding forms of AF. We also propose mechanical stretch as a new dimension to the concept "AF begets AF", in addition to underlying diseases. Finally, we discuss the mechanisms of these electro-anatomical alterations in a search for potential therapeutic strategies and the development of novel antiarrhythmic drugs targeted at the components of mechano-electrochemical signal transduction not only in cardiac myocytes, but also in cardiac non-myocyte cells.
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Affiliation(s)
- Roman Y Medvedev
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Saheed O Afolabi
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA; Department of Pharmacology and Therapeutics, University of Ilorin, Ilorin, Nigeria
| | - Daniel G P Turner
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Alexey V Glukhov
- Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA.
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2
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Piktel JS, Wan X, Kouk S, Laurita KR, Wilson LD. Beneficial Effect of Calcium Treatment for Hyperkalemia Is Not Due to "Membrane Stabilization". Crit Care Med 2024:00003246-990000000-00359. [PMID: 39046789 DOI: 10.1097/ccm.0000000000006376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
OBJECTIVES Hyperkalemia is a common life-threatening condition causing severe electrophysiologic derangements and arrhythmias. The beneficial effects of calcium (Ca2+) treatment for hyperkalemia have been attributed to "membrane stabilization," by restoration of resting membrane potential (RMP). However, the underlying mechanisms remain poorly understood. Our objective was to investigate the mechanisms underlying adverse electrophysiologic effects of hyperkalemia and the therapeutic effects of Ca2+ treatment. DESIGN Controlled experimental trial. SETTING Laboratory investigation. SUBJECTS Canine myocytes and tissue preparations. INTERVENTIONS AND MEASUREMENTS Optical action potentials and volume averaged electrocardiograms were recorded from the transmural wall of ventricular wedge preparations (n = 7) at baseline (4 mM potassium), hyperkalemia (8-12 mM), and hyperkalemia + Ca2+ (3.6 mM). Isolated myocytes were studied during hyperkalemia (8 mM) and after Ca2+ treatment (6 mM) to determine cellular RMP. MAIN RESULTS Hyperkalemia markedly slowed conduction velocity (CV, by 67% ± 7%; p < 0.001) and homogeneously shortened action potential duration (APD, by 20% ± 10%; p < 0.002). In all preparations, this resulted in QRS widening and the "sine wave" pattern observed in severe hyperkalemia. Ca2+ treatment restored CV (increase by 44% ± 18%; p < 0.02), resulting in narrowing of the QRS and normalization of the electrocardiogram, but did not restore APD. RMP was significantly elevated by hyperkalemia; however, it was not restored with Ca2+ treatment suggesting a mechanism unrelated to "membrane stabilization." In addition, the effect of Ca2+ was attenuated during L-type Ca2+ channel blockade, suggesting a mechanism related to Ca2+-dependent (rather than normally sodium-dependent) conduction. CONCLUSIONS These data suggest that Ca2+ treatment for hyperkalemia restores conduction through Ca2+-dependent propagation, rather than restoration of membrane potential or "membrane stabilization." Our findings provide a mechanistic rationale for Ca2+ treatment when hyperkalemia produces abnormalities of conduction (i.e., QRS prolongation).
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Affiliation(s)
- Joseph S Piktel
- Department of Emergency Medicine, Emergency Care and Research and Innovation, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Xiaoping Wan
- Department of Physiology & Cell Biology, The Ohio State University, College of Medicine, Columbus, OH
| | - Shalen Kouk
- Orthopedic Surgery and Sports Medicine, Mercy Clinic, St. Louis, MO
| | - Kenneth R Laurita
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
| | - Lance D Wilson
- Department of Emergency Medicine, Emergency Care and Research and Innovation, MetroHealth Campus, Case Western Reserve University, Cleveland, OH
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Hasebe H, Naruse Y, Sano M, Kurebayashi N, Morikawa S, Tsurumi N, Shiozawa T, Takano S, Ogano M, Kimura K, Miyajima K, Sugiura R, Henmi R, Muto M, Hosoya N, Mizukami A, Iguchi K, Atsumi A, Odagiri K, Kiyama Y, Maekawa Y. Delivery catheter system carries more physiological right ventricular septal pacing than stylet system. J Cardiovasc Electrophysiol 2024; 35:802-810. [PMID: 38409896 DOI: 10.1111/jce.16226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 02/02/2024] [Accepted: 02/14/2024] [Indexed: 02/28/2024]
Abstract
INTRODUCTION The Mt. FUJI multicenter trial demonstrated that a delivery catheter system had a higher rate of successful right ventricular (RV) lead deployment on the RV septum (RVS) than a conventional stylet system. In this subanalysis of the Mt. FUJI trial, we assessed the differences in electrocardiogram (ECG) parameters during RV pacing between a delivery catheter system and a stylet system and their associations with the lead tip positions. METHODS Among 70 patients enrolled in the Mt FUJI trial, ECG parameters, RV lead tip positions, and lead depth inside the septum assessed by computed tomography were compared between the catheter group (n = 36) and stylet group (n = 34). RESULTS The paced QRS duration (QRS-d), corrected paced QT (QTc), and JT interval (JTc) were significantly shorter in the catheter group than in the stylet group (QRS-d: 130 ± 19 vs. 142 ± 15 ms, p = .004; QTc: 476 ± 25 vs. 514 ± 20 ms, p < .001; JTc: 347 ± 24 vs. 372 ± 17 ms, p < .001). This superiority of the catheter group was maintained in a subgroup analysis of patients with an RV lead tip position at the septum. The lead depth inside the septum was greater in the catheter group than in the stylet group, and there was a significant negative correlation between the paced QRS-d and the lead depth. CONCLUSION Using a delivery catheter system carries more physiological depolarization and repolarization during RVS pacing and deeper screw penetration in the septum in comparison to conventional stylet system. The lead depth could have a more impact on the ECG parameters rather than the type of pacing lead.
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Affiliation(s)
- Hideyuki Hasebe
- Division of Arrhythmology, Shizuoka Saiseikai General Hospital, Shizuoka, Japan
| | - Yoshihisa Naruse
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Makoto Sano
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | | | - Shuji Morikawa
- Department of Cardiology, Chutoen General Medical Center, Kakegawa, Japan
| | - Naoki Tsurumi
- Department of Cardiology, Chutoen General Medical Center, Kakegawa, Japan
| | - Tomoyuki Shiozawa
- Department of Cardiology, Juntendo University Shizuoka Hospital, Izunokuni, Japan
| | - Shintaro Takano
- Department of Cardiology, Juntendo University Shizuoka Hospital, Izunokuni, Japan
| | - Michio Ogano
- Department of Cardiovascular Medicine, Shizuoka Medical Center, Sunto-gun, Japan
| | - Kei Kimura
- Department of Cardiovascular Medicine, Shizuoka Medical Center, Sunto-gun, Japan
| | - Keisuke Miyajima
- Department of Cardiology, Seirei Mikatahara General Hospital, Hamamatsu, Japan
| | - Ryo Sugiura
- Department of Cardiology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan
| | - Ryuta Henmi
- Department of Cardiology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan
| | - Masahiro Muto
- Department of Cardiology, Hamamatsu Medical Center, Hamamatsu, Japan
| | - Natsuko Hosoya
- Department of Cardiology, Hamamatsu Medical Center, Hamamatsu, Japan
| | - Akira Mizukami
- Department of Cardiology, Kameda Medical Center, Kamogawa, Japan
| | - Keisuke Iguchi
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Akiko Atsumi
- Department of Cardiology, Shintoshi Hospital, Iwata, Japan
| | - Keiichi Odagiri
- Center for Clinical Research, Hamamatsu University Hospital, Hamamatsu, Japan
| | - Yumi Kiyama
- Center for Clinical Research, Hamamatsu University Hospital, Hamamatsu, Japan
| | - Yuichiro Maekawa
- Division of Cardiology, Internal Medicine III, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Burattini M, Lo Muzio FP, Hu M, Bonalumi F, Rossi S, Pagiatakis C, Salvarani N, Fassina L, Luciani GB, Miragoli M. Unlocking cardiac motion: assessing software and machine learning for single-cell and cardioid kinematic insights. Sci Rep 2024; 14:1782. [PMID: 38245558 PMCID: PMC10799933 DOI: 10.1038/s41598-024-52081-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 01/12/2024] [Indexed: 01/22/2024] Open
Abstract
The heart coordinates its functional parameters for optimal beat-to-beat mechanical activity. Reliable detection and quantification of these parameters still represent a hot topic in cardiovascular research. Nowadays, computer vision allows the development of open-source algorithms to measure cellular kinematics. However, the analysis software can vary based on analyzed specimens. In this study, we compared different software performances in in-silico model, in-vitro mouse adult ventricular cardiomyocytes and cardioids. We acquired in-vitro high-resolution videos during suprathreshold stimulation at 0.5-1-2 Hz, adapting the protocol for the cardioids. Moreover, we exposed the samples to inotropic and depolarizing substances. We analyzed in-silico and in-vitro videos by (i) MUSCLEMOTION, the gold standard among open-source software; (ii) CONTRACTIONWAVE, a recently developed tracking software; and (iii) ViKiE, an in-house customized video kinematic evaluation software. We enriched the study with three machine-learning algorithms to test the robustness of the motion-tracking approaches. Our results revealed that all software produced comparable estimations of cardiac mechanical parameters. For instance, in cardioids, beat duration measurements at 0.5 Hz were 1053.58 ms (MUSCLEMOTION), 1043.59 ms (CONTRACTIONWAVE), and 937.11 ms (ViKiE). ViKiE exhibited higher sensitivity in exposed samples due to its localized kinematic analysis, while MUSCLEMOTION and CONTRACTIONWAVE offered temporal correlation, combining global assessment with time-efficient analysis. Finally, machine learning reveals greater accuracy when trained with MUSCLEMOTION dataset in comparison with the other software (accuracy > 83%). In conclusion, our findings provide valuable insights for the accurate selection and integration of software tools into the kinematic analysis pipeline, tailored to the experimental protocol.
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Affiliation(s)
- Margherita Burattini
- Department of Surgery, Dentistry and Maternity, University of Verona, Verona, Italy
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Francesco Paolo Lo Muzio
- Department of Medicine and Surgery, University of Parma, Parma, Italy
- Deutsches Herzzentrum Der Charité, Department of Cardiology, Angiology and Intensive Care Medicine, Berlin, Germany
| | - Mirko Hu
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Flavia Bonalumi
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Stefano Rossi
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Christina Pagiatakis
- Humanitas Research Hospital, IRCCS, Rozzano (Milan), Italy
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Nicolò Salvarani
- Humanitas Research Hospital, IRCCS, Rozzano (Milan), Italy
- Institute of Genetic and Biomedical Research (IRGB), UOS of Milan, National Research Council of Italy, Milan, Italy
| | - Lorenzo Fassina
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | | | - Michele Miragoli
- Department of Medicine and Surgery, University of Parma, Parma, Italy.
- Humanitas Research Hospital, IRCCS, Rozzano (Milan), Italy.
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Pastushkova LH, Goncharova AG, Rusanov VB, Nosovsky AM, Kashirina DN, Popova OV, Larina IM. Correlation between proteome changes and synchrony of cardiac electrical excitation under 3-day «dry immersion» conditions. Front Physiol 2023; 14:1285802. [PMID: 38107479 PMCID: PMC10722197 DOI: 10.3389/fphys.2023.1285802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/24/2023] [Indexed: 12/19/2023] Open
Affiliation(s)
| | | | | | | | | | - O. V. Popova
- State Scientific Center of the Russian Federation, Institute of Medical and Biological Problems Russian Academy of Sciences, Moscow, Russia
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6
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Wu X, Hu W, Song L, Chen W, Zhou Y, Zhou L, Ou Z, Qiu Z. Use of acoustic cardiography to assess left ventricular electromechanical synchronization during left bundle branch pacing. Heart Rhythm O2 2023; 4:632-640. [PMID: 37936667 PMCID: PMC10626181 DOI: 10.1016/j.hroo.2023.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023] Open
Abstract
Background Left bundle branch pacing (LBBP) is a physiological pacing that captures the main left bundle or its proximal branch. Electromechanical activation time (EMAT) is an acoustic cardiographic metric that provides a simple method for evaluating left ventricular (LV) synchrony. Prolonged EMAT reflects impaired LV electromechanical coupling. Objective The purpose of this study was to explore whether EMAT can confirm that LBBP produces more satisfactory LV electromechanical synchronization than conventional right ventricular pacing modalities. Methods Patients with standard pacing indications and narrow QRS duration were recruited for this study. Unipolar pacing under 3 different modalities-right ventricular apical pacing (RVAP), right ventricular high septal pacing (RVHSP), and LBBP-were successively performed in each patient. Pacing parameters, echocardiographic characteristics, and acoustic cardiographic parameters at different pacing modalities and during normal rhythm were collected. Results A total of 55 patients were enrolled, and all had successful LBBP. Left ventricular activation time (LVAT) was significantly associated with EMAT, with LVAT vs EMAT correlation coefficient of 0.665 (P <.001). LVAT during LBBP was shorter than that during RVHSP (51.93 ± 2.732 ms vs 85.59 ± 2.240 ms; P <.001). EMAT of LBBP was significantly lower than either RVAP or RVHSP (95.44 ± 1.794 ms vs 143.32 ± 2.376 ms, and 132.22 ± 1.872 ms; both P <.001) but was similar to that of intrinsic rhythm (95.37 ± 2.271 ms; P = .862). Conclusion We found EMAT significantly prolonged in RVHSP and RVAP but not in the LBBP mode. This finding indicates superior electromechanical synchronization in patients having LBBP. EMAT measurement could be an additional method for identifying the ideal pacing position.
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Affiliation(s)
- Xianhao Wu
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei Hu
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lei Song
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wanlan Chen
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yi Zhou
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lihong Zhou
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ziming Ou
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhaohui Qiu
- Department of Cardiology, Shanghai Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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van Nieuwenhoven FA, Schroen B, Barile L, van Middendorp L, Prinzen FW, Auricchio A. Plasma Extracellular Vesicles as Liquid Biopsy to Unravel the Molecular Mechanisms of Cardiac Reverse Remodeling Following Resynchronization Therapy? J Clin Med 2023; 12:jcm12020665. [PMID: 36675594 PMCID: PMC9862724 DOI: 10.3390/jcm12020665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Cardiac resynchronization therapy (CRT) has become a valuable addition to the treatment options for heart failure, in particular for patients with disturbances in electrical conduction that lead to regionally different contraction patterns (dyssynchrony). Dyssynchronous hearts show extensive molecular and cellular remodeling, which has primarily been investigated in experimental animals. Evidence showing that at least several miRNAs play a role in this remodeling is increasing. A comparison of results from measurements in plasma and myocardial tissue suggests that plasma levels of miRNAs may reflect the expression of these miRNAs in the heart. Because many miRNAs released in the plasma are included in extracellular vesicles (EVs), which protect them from degradation, measurement of myocardium-derived miRNAs in peripheral blood EVs may open new avenues to investigate and monitor (reverse) remodeling in dyssynchronous and resynchronized hearts of patients.
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Affiliation(s)
- Frans A. van Nieuwenhoven
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Blanche Schroen
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Lucio Barile
- Laboratory for Cardiovascular Theranostics, Istituto Cardiocentro Ticino, 6900 Lugano, Switzerland
| | - Lars van Middendorp
- Department of Cardiothoracic Surgery, Maastricht University Medical Center, 6200 MD Maastricht, The Netherlands
| | - Frits W. Prinzen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, The Netherlands
- Correspondence:
| | - Angelo Auricchio
- Department of Cardiology, Istituto Cardiocentro Ticino, Ente Ospedaliero Cantonale, 6900 Lugano, Switzerland
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Verzaal NJ, van Deursen CJM, Pezzuto S, Wecke L, van Everdingen WM, Vernooy K, Delhaas T, Auricchio A, Prinzen FW. Synchronization of repolarization after cardiac resynchronization therapy: A combined clinical and modeling study. J Cardiovasc Electrophysiol 2022; 33:1837-1846. [PMID: 35662306 PMCID: PMC9539692 DOI: 10.1111/jce.15581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The changes in ventricular repolarization after cardiac resynchronization therapy (CRT) are poorly understood. This knowledge gap is addressed using a multimodality approach including electrocardiographic and echocardiographic measurements in patients and using patient-specific computational modeling. METHODS In 33 patients electrocardiographic and echocardiographic measurements were performed before and at various intervals after CRT, both during CRT-ON and temporary CRT-OFF. T-wave area was calculated from vectorcardiograms, and reconstructed from the 12-lead electrocardiography (ECG). Computer simulations were performed using a patient-specific eikonal model of cardiac activation with spatially varying action potential duration (APD) and repolarization rate, fit to a patient's ECG. RESULTS During CRT-ON T-wave area diminished within a day and remained stable thereafter, whereas QT-interval did not change significantly. During CRT-OFF T-wave area doubled within 5 days of CRT, while QT-interval and peak-to-end T-wave interval hardly changed. Left ventricular (LV) ejection fraction only increased significantly increased after 1 month of CRT. Computer simulations indicated that the increase in T-wave area during CRT-OFF can be explained by changes in APD following chronic CRT that are opposite to the change in CRT-induced activation time. These APD changes were associated with a reduction in LV dispersion in repolarization during chronic CRT. CONCLUSION T-wave area during CRT-OFF is a sensitive marker for adaptations in ventricular repolarization during chronic CRT that may include a reduction in LV dispersion of repolarization.
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Affiliation(s)
- Nienke J. Verzaal
- Department of Physiology, Cardiovascular Research Institute MaastrichtMaastricht UniversityMaastrichtThe Netherlands
| | | | - Simone Pezzuto
- Center for Computational Medicine in Cardiology, Euler InstituteUniversità della Svizzera italianaLuganoSwitzerland
| | - Liliane Wecke
- Heart ClinicCapio St. Göran's Hospital, Sankt Göransplan 1StockholmSweden
| | | | - Kevin Vernooy
- Department of CardiologyMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Tammo Delhaas
- Department of Biomedical EngineeringMaastricht UniversityMaastrichtThe Netherlands
| | - Angelo Auricchio
- Center for Computational Medicine in Cardiology, Euler InstituteUniversità della Svizzera italianaLuganoSwitzerland
- Department of CardiologyIstituto Cardiocentro TicinoLuganoSwitzerland
| | - Frits W. Prinzen
- Department of Physiology, Cardiovascular Research Institute MaastrichtMaastricht UniversityMaastrichtThe Netherlands
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Oomen PJA, Phung TKN, Weinberg SH, Bilchick KC, Holmes JW. A rapid electromechanical model to predict reverse remodeling following cardiac resynchronization therapy. Biomech Model Mechanobiol 2022; 21:231-247. [PMID: 34816336 PMCID: PMC9241386 DOI: 10.1007/s10237-021-01532-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 10/22/2021] [Indexed: 10/19/2022]
Abstract
Cardiac resynchronization therapy (CRT) is an effective therapy for patients who suffer from heart failure and ventricular dyssynchrony such as left bundle branch block (LBBB). When it works, it reverses adverse left ventricular (LV) remodeling and the progression of heart failure. However, CRT response rate is currently as low as 50-65%. In theory, CRT outcome could be improved by allowing clinicians to tailor the therapy through patient-specific lead locations, timing, and/or pacing protocol. However, this also presents a dilemma: there are far too many possible strategies to test during the implantation surgery. Computational models could address this dilemma by predicting remodeling outcomes for each patient before the surgery takes place. Therefore, the goal of this study was to develop a rapid computational model to predict reverse LV remodeling following CRT. We adapted our recently developed computational model of LV remodeling to simulate the mechanics of ventricular dyssynchrony and added a rapid electrical model to predict electrical activation timing. The model was calibrated to quantitatively match changes in hemodynamics and global and local LV wall mass from a canine study of LBBB and CRT. The calibrated model was used to investigate the influence of LV lead location and ischemia on CRT remodeling outcome. Our model results suggest that remodeling outcome varies with both lead location and ischemia location, and does not always correlate with short-term improvement in QRS duration. The results and time frame required to customize and run this model suggest promise for this approach in a clinical setting.
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Affiliation(s)
- Pim J. A. Oomen
- Department of Biomedical Engineering, University of Virginia, Box 800759, Health System, Charlottesville, VA 22903, USA
- Department of Medicine, University of Virginia, Box 800158, Health System, Charlottesville, VA 22903, USA
| | - Thien-Khoi N. Phung
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Seth H. Weinberg
- Department of Biomedical Engineering, The Ohio State University, 140 W 19th Ave Columbus, Columbus, OH 43210, USA
| | - Kenneth C. Bilchick
- Department of Medicine, University of Virginia, Box 800158, Health System, Charlottesville, VA 22903, USA
| | - Jeffrey W. Holmes
- Department of Biomedical Engineering, University of Virginia, Box 800759, Health System, Charlottesville, VA 22903, USA
- School of Engineering, University of Alabama at Birmingham, 1075 13th St S, Birmingham, AL 35233, USA
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10
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AKDİ A, ÖZEKE Ö. Tp-e interval and Tp-e/JT ratio before and after catheter ablation in patients with Wolff Parkinson White syndrome. JOURNAL OF HEALTH SCIENCES AND MEDICINE 2022. [DOI: 10.32322/jhsm.1017684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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11
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Chakraborty P, Suszko AM, Viswanathan K, Sheikholeslami K, Spears D, Adler A, Woo A, Rakowski H, Chauhan VS. Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias. J Am Heart Assoc 2021; 10:e022036. [PMID: 34854315 PMCID: PMC9075383 DOI: 10.1161/jaha.121.022036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background Unlike T‐wave alternans (TWA), the relation between QRS alternans (QRSA) and ventricular arrhythmia (VA) risk has not been evaluated in hypertrophic cardiomyopathy (HCM). We assessed microvolt QRSA/TWA in relation to HCM risk factors and late VA outcomes in HCM. Methods and Results Prospectively enrolled patients with HCM (n=130) with prophylactic implantable cardioverter‐defibrillators underwent digital 12‐lead ECG recordings during ventricular pacing (100–120 beats/min). QRSA/TWA was quantified using the spectral method. Patients were categorized as QRSA+ and/or TWA+ if sustained alternans was present in ≥2 precordial leads. The VA end point was appropriate implantable cardioverter‐defibrillator therapy over 5 years of follow‐up. QRSA+ and TWA+ occurred together in 28% of patients and alone in 7% and 7% of patients, respectively. QRSA magnitude increased with pacing rate (1.9±0.6 versus 6.2±2.0 µV; P=0.006). Left ventricular thickness was greater in QRSA+ than in QRSA− patients (22±7 versus 20±6 mm; P=0.035). Over 5 years follow‐up, 17% of patients had VA. The annual VA rate was greater in QRSA+ versus QRSA− patients (5.8% versus 2.0%; P=0.006), with the QRSA+/TWA− subgroup having the greatest rate (13.3% versus 2.6%; P<0.001). In those with <2 risk factors, QRSA− patients had a low annual VA rate compared QRSA+ patients (0.58% versus 7.1%; P=0.001). Separate Cox models revealed QRSA+ (hazard ratio [HR], 2.9 [95% CI, 1.2–7.0]; P=0.019) and QRSA+/TWA− (HR, 7.9 [95% CI, 2.9–21.7]; P<0.001) as the most significant VA predictors. TWA and HCM risk factors did not predict VA. Conclusions In HCM, microvolt QRSA is a novel, rate‐dependent phenomenon that can exist without TWA and is associated with greater left ventricular thickness. QRSA increases VA risk 3‐fold in all patients, whereas the absence of QRSA confers low VA risk in patients with <2 risk factors. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02560844.
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Affiliation(s)
- Praloy Chakraborty
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Adrian M Suszko
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Karthik Viswanathan
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Kimia Sheikholeslami
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Danna Spears
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Arnon Adler
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Anna Woo
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Harry Rakowski
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Vijay S Chauhan
- Division of Cardiology Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
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12
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Ballet A, Mulleman R, Vandermotte M. The heart remembers what the mind forgets. Acta Clin Belg 2021; 76:310-313. [PMID: 31996105 DOI: 10.1080/17843286.2020.1724449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Background: Cardiac memory, also known as the Chatterjee phenomenon, is a poorly understood, under-recognized but important and benign cause of T-wave inversions. After a period of abnormal ventricular activation, such as ventricular pacing, intermittent left bundle branch block or pre-excitation, the heart 'remembers' and mirrors its repolarization in the direction of the previous QRS. It usually manifests as T-wave inversions that can linger up to weeks after the provocative event.Case summary: An 87-year-old man with extensive cardiovascular history and risk factors presented to the emergency department with shortness of breath and chest pain. An ECG taken on admission revealed deep widespread T wave inversions. Serial high sensitive cardiac troponin (hs-cTn) however remained negative (<10 ng/ml) with a negative D-dimer. Upon reviewing previous ECGs and the medical history, the patient was diagnosed with cardiac memory, which required no further treatment.Conclusion: Cardiac memory should be considered in any patient with a ventricular pacemaker that presents with narrow QRS rhythm and T-wave changes suggestive of ischemia. Although it remains a diagnosis of exclusion, recognizing this important clinical entity can prevent unnecessary admissions, expensive diagnostic tests and invasive procedures.
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Affiliation(s)
- Arne Ballet
- Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Ritchie Mulleman
- Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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13
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Arrhythmias in Brugada Syndrome: Defective Depolarization, Repolarization or Both? JACC Clin Electrophysiol 2021; 7:271-272. [PMID: 33602411 DOI: 10.1016/j.jacep.2020.12.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 12/20/2020] [Indexed: 11/24/2022]
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14
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Suszko A, Nayyar S, Labos C, Nanthakumar K, Pinter A, Crystal E, Chauhan VS. Microvolt QRS Alternans Without Microvolt T-Wave Alternans in Human Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias. J Am Heart Assoc 2020; 9:e016461. [PMID: 32806990 PMCID: PMC7660784 DOI: 10.1161/jaha.119.016461] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background Action potential alternans can induce ventricular tachyarrhythmias and manifest on the surface ECG as T‐wave alternans (TWA) and QRS alternans (QRSA). We sought to evaluate microvolt QRSA in cardiomyopathy patients in relation to TWA and ventricular tachyarrhythmia outcomes. Methods and Results Prospectively enrolled cardiomyopathy patients (n=100) with prophylactic defibrillators had 12‐lead ECGs recorded during ventricular pacing from 100 to 120 beats/min. QRSA and TWA were quantified in moving 128‐beat segments using the spectral method. Segments were categorized as QRSA positive (QRSA+) and/or TWA positive (TWA+) based on ≥2 precordial leads having alternans magnitude >0 and signal:noise >3. Patients were similarly categorized based on having ≥3 consecutive segments with alternans. TWA+ and QRSA+ occurred together in 31% of patients and alone in 18% and 14% of patients, respectively. Although TWA magnitude (1.4±0.4 versus 4.7±1.0 µV, P<0.01) and proportion of TWA+ studies (16% versus 46%, P<0.01) increased with rate, QRSA did not change. QRS duration was longer in QRSA+ than QRSA‐negative patients (138±23 versus 113±26 ms, P<0.01). At 3.5 years follow‐up, appropriate defibrillator therapy or sustained ventricular tachyarrhythmia was greater in QRSA+ than QRSA‐negative patients (30% versus 8%, P=0.02) but similar in TWA+ and TWA‐negative patients. Among QRSA+ patients, the event rate was greater in those without TWA (62% versus 21%, P=0.02). Multivariable Cox analysis revealed QRSA+ (hazard ratio [HR], 4.6; 95% CI, 1.5–14; P=0.009) and QRS duration >120 ms (HR, 4.1; 95% CI, 1.3–12; P=0.014) to predict events. Conclusions Microvolt QRSA is novel phenomenon in cardiomyopathy patients that can exist without TWA and is associated with QRS prolongation. QRSA increases the risk of ventricular tachyarrhythmia 4‐fold, which merits further study as a risk stratifier.
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Affiliation(s)
- Adrian Suszko
- Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | - Sachin Nayyar
- Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
| | | | | | - Arnold Pinter
- Division of Cardiology St. Michael's Hospital Toronto Ontario Canada
| | - Eugene Crystal
- Division of Cardiology Sunnybrook Health Sciences Center Toronto Ontario Canada
| | - Vijay S Chauhan
- Peter Munk Cardiac Center University Health Network Toronto Ontario Canada
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15
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Suran MCB, Margulescu AD, Bruja R, Siliste C, Vinereanu D. Surface ECG criteria can discriminate post-septal pacing cardiac memory from ischemic T wave inversions. J Electrocardiol 2020; 58:10-17. [PMID: 31678715 DOI: 10.1016/j.jelectrocard.2019.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/23/2019] [Accepted: 10/11/2019] [Indexed: 10/25/2022]
Abstract
Cardiac memory (CM) refers to transient T wave changes that appear after cessation of a period of abnormal ventricular activation, such as right ventricular (RV) pacing. ECG criteria for differentiating post-pacing CM from ischemia-induced T wave changes were previously published only for apical, but not for septal RV pacing. AIM To find ECG criteria for discriminating post-septal pacing CM from ischemic T wave inversions. METHODS ECGs were analyzed in 2 groups: CM (n = 23) and ischemia (n = 26). CM was induced by 2 weeks of DDD pacing with a short AV delay. Ischemic patients were grouped by culprit vessel: left anterior descending (LAD), circumflex (Cx), right coronary artery (RCA). RESULTS CM was visible on the ECG after 1 week of ventricular pacing, started to disappear in <1 week after pacing cessation and was completely reversible within 4 weeks of pacing cessation. T wave axis differed between CM (75.8 ± 18.5°) and Cx (-25.2 ± 25.5°, p < 0.01) and RCA (-18.3 ± 18.9°, p < 0.01) groups, but not compared to LAD group (96.4 ± 65.0°, p = 0.17). The combination of (1) positive T wave in aVF; and (2) (i) T wave amplitude in aVF ≥ the absolute value of the most negative precordial T wave, or (ii) positive T wave in V5 and positive or isoelectric T wave in lead I identified CM from all ischemia with a sensitivity of 91% and a specificity of 92%. CONCLUSION ECG criteria can discriminate post-septal RV pacing CM from ischemic changes with high sensitivity and specificity.
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Affiliation(s)
- Maria-Claudia-Berenice Suran
- University of Medicine and Pharmacy "Carol Davila" Bucharest, Bucharest, Romania; Department of Cardiology, University and Emergency Hospital of Bucharest, Bucharest, Romania
| | - Andrei-Dumitru Margulescu
- University of Medicine and Pharmacy "Carol Davila" Bucharest, Bucharest, Romania; Department of Cardiology, University and Emergency Hospital of Bucharest, Bucharest, Romania; Department of Cardiology, Morriston Hospital NHS Trust, Swansea, United Kingdom
| | - Ramona Bruja
- Department of Cardiology, University and Emergency Hospital of Bucharest, Bucharest, Romania
| | - Calin Siliste
- University of Medicine and Pharmacy "Carol Davila" Bucharest, Bucharest, Romania; Department of Cardiology, University and Emergency Hospital of Bucharest, Bucharest, Romania.
| | - Dragos Vinereanu
- University of Medicine and Pharmacy "Carol Davila" Bucharest, Bucharest, Romania; Department of Cardiology, University and Emergency Hospital of Bucharest, Bucharest, Romania
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16
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Piktel JS, Wilson LD. Translational Models of Arrhythmia Mechanisms and Susceptibility: Success and Challenges of Modeling Human Disease. Front Cardiovasc Med 2019; 6:135. [PMID: 31552276 PMCID: PMC6748164 DOI: 10.3389/fcvm.2019.00135] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/27/2019] [Indexed: 01/10/2023] Open
Abstract
We discuss large animal translational models of arrhythmia susceptibility and sudden cardiac death, focusing on important considerations when interpreting the data derived before applying them to human trials. The utility of large animal models of arrhythmia and the pros and cons of specific translational large animals used will be discussed, including the necessary tradeoffs between models designed to derive mechanisms vs. those to test therapies. Recent technical advancements which can be applied to large animal models of arrhythmias to better elucidate mechanistic insights will be introduced. Finally, some specific examples of past successes and challenges in translating the results of large animal models of arrhythmias to clinical trials and practice will be examined, and common themes regarding the success and failure of translating studies to therapy in man will be discussed.
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Affiliation(s)
| | - Lance D. Wilson
- Department of Emergency Medicine, Emergency Care Research Institute and Heart and Vascular Research Center, MetroHealth Campus of Case Western Reserve University, Cleveland, OH, United States
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17
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Sakhnova TA, Blinova EV, Belevskaya AA, Saidova MA, Arkhipova OA. Comparison of the integral indices of the vectorcardiogram with the data of echocardiography in patients with idiopathic and chronic thromboembolic pulmonary hypertension. TERAPEVT ARKH 2019; 91:11-16. [PMID: 31094452 DOI: 10.26442/00403660.2019.03.000043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
AIM The aim of the work is to compare vectorcardiographic (VCG) variables - spatial QRS-T angle and electrocardiographic ventricular gradient (VG) with echocardiography (EchoCG) data in patients with idiopathic pulmonary hypertension (IPH) and chronic thromboembolic pulmonary hypertension (CTEPH). MATERIALS AND METHODS In 40 patients with IPH and 40 patients with CTEPH at the age of 45±12 years, systolic pulmonary artery pressure (SPAP); the sizes of heart chambers, parameters of RV systolic and diastolic function were evaluated with EchoCG. The QRS-T and VG angles were calculated on the VCG, derived from 12-lead digital ECG. RESULTS In all patients SPAP was greater than 40 mm Hg (mean 83±18 mm Hg), EchoCG data indicated hypertrophy and dilatation of RV, its systolic and diastolic function; dilatation of the right atrium (RA). Prognostically unfavorable changes in EchoCG were observed: the presence of pericardial effusion in 35 (44%) patients, RA area greater than 26 cm2 in 18 (23%) patients; TAPSE less than 1.5 cm in 37 (46%) patients. EchoCG and VCG variables had statistically significant differences in patients with III-IV functional class in comparison with I-II functional class. Statistically significant moderate correlations between VCG and EchoCG variables were revealed. VCG variables allowed to separate patient groups with the presence and absence of prognostically unfavorable changes in EchoCG with sensitivity from 54 to 78% and specificity from 66 to 87%. CONCLUSION In patients with IPH and CTEPH, changes of QRS-T angle and VG correlate with SPAP, the size of RV and RA, parameters of RV systolic and diastolic function. The possibility of the use of QRS-T angle and VG for the detection of patients with prognostically unfavorable echocardiographic changes in the general group of patients with IPH and CTEPH has been shown.
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Affiliation(s)
- T A Sakhnova
- A.L. Myasnikov Research Institute of Cardiology of National Medical Research Center of Сardiology of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - E V Blinova
- A.L. Myasnikov Research Institute of Cardiology of National Medical Research Center of Сardiology of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - A A Belevskaya
- A.L. Myasnikov Research Institute of Cardiology of National Medical Research Center of Сardiology of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - M A Saidova
- A.L. Myasnikov Research Institute of Cardiology of National Medical Research Center of Сardiology of the Ministry of Health of the Russian Federation, Moscow, Russia
| | - O A Arkhipova
- A.L. Myasnikov Research Institute of Cardiology of National Medical Research Center of Сardiology of the Ministry of Health of the Russian Federation, Moscow, Russia
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18
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Vohra J. Editorial: Cardiac or T wave memory after radiofrequency ablation of right ventricular outflow tract ectopics. J Cardiovasc Electrophysiol 2019; 30:1557-1559. [PMID: 31165545 DOI: 10.1111/jce.14007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 05/27/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Jitendra Vohra
- Cardiology Department, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
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19
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Nuzhny VP, Kibler NA, Shmakov DN. Irregular Ventricular Tachycardia as a Mechanism of Stabilization of Mechanoelectrical Processes in Canine Heart under Conditions of Antiorthostatic Hypokinesia. Bull Exp Biol Med 2018; 166:207-212. [PMID: 30488217 DOI: 10.1007/s10517-018-4315-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Indexed: 11/25/2022]
Abstract
We studied electrophysiological mechanisms of ventricular arrhythmias in dogs (n=7) under conditions of antiorthostatic hypokinesia (head-down tilt 45°). Abnormal transmural heterogeneity of repolarization in the base and apex of the left ventricle and increased dispersion of myocardial repolarization were revealed. By minute 30 of antiorthostatic hypokinesia, an increase in the duration of repolarization was revealed after a period of ventricular arrhythmia in all segments and regions of heart ventricles, which was accompanied by impairment of the pumping function of the heart. A hypothesis on the physiological role of ventricular tachycardia as a mechanism of electromechanical homeostatic stabilization in the heart was proposed. The obtained results suggest that under conditions of antiorthostatic hypokinesia, canine heart after a paroxysm of irregular ventricular tachycardia becomes more resistant to arrhythmia.
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Affiliation(s)
- V P Nuzhny
- Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Russia
| | - N A Kibler
- Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Russia.
| | - D N Shmakov
- Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Russia
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20
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Wu D, Huang D, Li LL, Ni P, Li XX, Wang B, Han YN, Shao XQ, Zhao D, Chu WF, Li BY. TGF-β1-PML SUMOylation-peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) form a positive feedback loop to regulate cardiac fibrosis. J Cell Physiol 2018; 234:6263-6273. [PMID: 30246389 DOI: 10.1002/jcp.27357] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/17/2018] [Indexed: 11/11/2022]
Abstract
Transforming growth factor-β (TGF-β) signaling pathway is involved in fibrosis in most, if not all forms of cardiac diseases. Here, we evaluate a positive feedback signaling the loop of TGF-β1/promyelocytic leukemia (PML) SUMOylation/Pin1 promoting the cardiac fibrosis. To test this hypothesis, the mice underwent transverse aortic constriction (3 weeks) were developed and the morphological evidence showed obvious interstitial fibrosis with TGF-β1, Pin1 upregulation, and increase in PML SUMOylation. In neonatal mouse cardiac fibroblasts (NMCFs), we found that exogenous TGF-β1 induced the upregulation of TGF-β1 itself in a time- and dose-dependent manner, and also triggered the PML SUMOylation and the formation of PML nuclear bodies (PML-NBs), and consequently recruited Pin1 into nuclear to colocalize with PML. Pharmacological inhibition of TGF-β signal or Pin1 with LY364947 (3 μM) or Juglone (3 μM), the TGF-β1-induced PML SUMOylation was reduced significantly with downregulation of the messenger RNA and protein for TGF-β1 and Pin1. To verify the cellular function of PML by means of gain- or loss-of-function, the positive feedback signaling loop was enhanced or declined, meanwhile, TGF-β-Smad signaling pathway was activated or weakened, respectively. In summary, we uncovered a novel reciprocal loop of TGF-β1/PML SUMOylation/Pin1 leading to myocardial fibrosis.
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Affiliation(s)
- Di Wu
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Di Huang
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Liang-Liang Li
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Ping Ni
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Xiu-Xian Li
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Bing Wang
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yan-Na Han
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Xiao-Qi Shao
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Dan Zhao
- Departments of Clinical Pharmacy and Cardiology, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, The 2nd Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Wen-Feng Chu
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Bai-Yan Li
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
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21
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Li N, Zhou H, Tang Q. miR-133: A Suppressor of Cardiac Remodeling? Front Pharmacol 2018; 9:903. [PMID: 30174600 PMCID: PMC6107689 DOI: 10.3389/fphar.2018.00903] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/23/2018] [Indexed: 01/28/2023] Open
Abstract
Cardiac remodeling, which is characterized by mechanical and electrical remodeling, is a significant pathophysiological process involved in almost all forms of heart diseases. MicroRNAs (miRNAs) are a group of non-coding RNAs of 20–25 nucleotides in length that primarily regulate gene expression by promoting mRNA degradation or post-transcriptional repression in a sequence-specific manner. Three miR-133 genes have been identified in the human genome, miR-133a-1, miR-133a-2, and miR-133b, which are located on chromosomes 18, 20, and 6, respectively. These miRNAs are mainly expressed in muscle tissues and appear to repress the expression of non-muscle genes. Based on accumulating evidence, miR-133 participates in the proliferation, differentiation, survival, hypertrophic growth, and electrical conduction of cardiac cells, which are essential for cardiac fibrosis, cardiac hypertrophy, and arrhythmia. Nevertheless, the roles of miR-133 in cardiac remodeling are ambiguous, and the mechanisms are also sophisticated, involving many target genes and signaling pathways, such as RhoA, MAPK, TGFβ/Smad, and PI3K/Akt. Therefore, in this review, we summarize the critical roles of miR-133 and its potential mechanisms in cardiac remodeling.
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Affiliation(s)
- Ning Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Heng Zhou
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
| | - Qizhu Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Cardiovascular Research Institute, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cardiology, Wuhan, China
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22
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Cvijić M, Antolič B, Klemen L, Zupan I. Repolarization heterogeneity in patients with cardiac resynchronization therapy and its relation to ventricular tachyarrhythmias. Heart Rhythm 2018; 15:1784-1790. [PMID: 29908369 DOI: 10.1016/j.hrthm.2018.06.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Cardiac resynchronization therapy (CRT) has been shown to induce left ventricular reverse remodeling, but little is known about its influence on ventricular repolarization. OBJECTIVE The purpose of this study was to evaluate changes in ventricular repolarization of native conduction after CRT and its relation to ventricular tachycardia (VT) and ventricular fibrillation (VF) during long-term follow-up. METHODS We prospectively included 64 patients with heart failure treated with CRT. QT interval, TpTe, and TpTe/QT ratio were analyzed from 20-minute high-resolution ECGs that were recorded at baseline and 1, 3, 6, 9, and 12 months after CRT implantation. CRT was temporary inhibited during follow-up to record intrinsic ECG. Patients with a decrease of left ventricular end-systolic volume ≥15% at 12-month follow-up (mid-term follow-up) were considered as responders. Occurrences of VT/VF during follow-up were noted. RESULTS Significant increase of repolarization heterogeneity in the first months after implantation was observed (P <.05) but then declined during 12 months of follow-up. Patients with VT/VF during long-term follow-up had higher repolarization heterogeneity at mid-term follow-up than patients without VT/VF (TpTe/QT ratio: 0.263 [0.204-0.278] vs 0.225 [0.204-0.239]; P = .045). Echocardiographic response at mid-term follow-up did not significantly influence the rate of VT/VF (log-rank P = .252). In multivariate Cox regression analysis, only high repolarization heterogeneity at mid-term follow-up (TpTe/QT ratio >0.260) was independently associated with high risk of VT/VF (hazard ratio 4.29; 95% confidence interval 1.40-13.15; P = .011). CONCLUSION CRT induces time-dependent changes in repolarization parameters in the first year after implantation. High repolarization heterogeneity at mid-term follow-up was associated with higher rate of VT/VF during long-term follow-up.
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Affiliation(s)
- Marta Cvijić
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia.
| | - Bor Antolič
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Luka Klemen
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Igor Zupan
- Department of Cardiology, University Medical Centre Ljubljana, Ljubljana, Slovenia
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23
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Nguyên UC, Verzaal NJ, van Nieuwenhoven FA, Vernooy K, Prinzen FW. Pathobiology of cardiac dyssynchrony and resynchronization therapy. Europace 2018; 20:1898-1909. [DOI: 10.1093/europace/euy035] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/16/2018] [Indexed: 02/04/2023] Open
Affiliation(s)
- Uyên Châu Nguyên
- Department of Physiology, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, ER Maastricht, The Netherlands
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, ER Maastricht, The Netherlands
| | - Nienke J Verzaal
- Department of Physiology, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, ER Maastricht, The Netherlands
| | - Frans A van Nieuwenhoven
- Department of Physiology, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, ER Maastricht, The Netherlands
| | - Kevin Vernooy
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, ER Maastricht, The Netherlands
| | - Frits W Prinzen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Universiteitssingel 50, ER Maastricht, The Netherlands
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24
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Wilson LD, Deschenes I. Strategically targeting calcium: Altering activation sequence to reverse remodel the failing ventricle. Heart Rhythm 2018; 15:1550-1551. [PMID: 29689310 DOI: 10.1016/j.hrthm.2018.04.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Indexed: 11/19/2022]
Affiliation(s)
- Lance D Wilson
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; Department of Emergency Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio
| | - Isabelle Deschenes
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio.
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25
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Yin D, Chen M, Yang N, Wu AZ, Xu D, Tsai WC, Yuan Y, Tian Z, Chan YH, Shen C, Chen Z, Lin SF, Weiss JN, Chen PS, Everett TH. Role of apamin-sensitive small conductance calcium-activated potassium currents in long-term cardiac memory in rabbits. Heart Rhythm 2018; 15:761-769. [PMID: 29325977 DOI: 10.1016/j.hrthm.2018.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Apamin-sensitive small conductance calcium-activated K current (IKAS) is up-regulated during ventricular pacing and masks short-term cardiac memory (CM). OBJECTIVE The purpose of this study was to determine the role of IKAS in long-term CM. METHODS CM was created with 3-5 weeks of ventricular pacing and defined by a flat or inverted T wave off pacing. Epicardial optical mapping was performed in both paced and normal ventricles. Action potential duration (APD80) was determined during right atrial pacing. Ventricular stability was tested before and after IKAS blockade. Four paced hearts and 4 normal hearts were used for western blotting and histology. RESULTS There were no significant differences in either echocardiographic parameters or fibrosis levels between groups. Apamin induced more APD80 prolongation in CM than in normal ventricles (mean [95% confidence interval]: 9.6% [8.8%-10.5%] vs 3.1% [1.9%-4.3%]; P <.001). Apamin significantly lengthened APD80 in the CM model at late activation sites, indicating significant IKAS up-regulation at those sites. The CM model also had altered Ca2+ handling, with the 50% Ca2+ transient duration and amplitude increased at distal sites compared to a proximal site (near the pacing site). After apamin, the CM model had increased ventricular fibrillation (VF) inducibility (paced vs control: 33/40 (82.5%) vs 7/20 (35%); P <.001) and longer VF durations (124 vs 26 seconds; P <.001). CONCLUSION Chronic ventricular pacing increases Ca2+ transients at late activation sites, which activates IKAS to maintain repolarization reserve. IKAS blockade increases VF vulnerability in chronically paced rabbit ventricles.
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Affiliation(s)
- Dechun Yin
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cardiology, First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Mu Chen
- Department of Cardiology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Na Yang
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Gynecological and Obstetric Ultrasound, First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Adonis Z Wu
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan
| | - Dongzhu Xu
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Wei-Chung Tsai
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yuan Yuan
- Department of Cardiothoracic Surgery, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhipeng Tian
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cardiology, Central Hospital Affiliated to Shenyang Medical College, Shenyang, Liaoning, China
| | - Yi-Hsin Chan
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan
| | - Changyu Shen
- Richard and Susan Smith Center for Outcomes Research in Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Zhenhui Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Shien-Fong Lin
- Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan
| | - James N Weiss
- Departments of Medicine and Physiology, University of California, Los Angeles, California
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Thomas H Everett
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
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Mechano-electrical feedback in the clinical setting: Current perspectives. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:365-375. [DOI: 10.1016/j.pbiomolbio.2017.06.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 06/01/2017] [Accepted: 06/02/2017] [Indexed: 12/13/2022]
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Stams TRG, Dunnink A, van Everdingen WM, Beekman HDM, van der Nagel R, Kok B, Bierhuizen MFA, Cramer MJ, Meine M, Vos MA. Deleterious acute and chronic effects of bradycardic right ventricular apex pacing: consequences for arrhythmic outcome. Basic Res Cardiol 2017. [DOI: 10.1007/s00395-017-0636-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pressure-overload-induced angiotensin-mediated early remodeling in mouse heart. PLoS One 2017; 12:e0176713. [PMID: 28464037 PMCID: PMC5413013 DOI: 10.1371/journal.pone.0176713] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 04/15/2017] [Indexed: 11/19/2022] Open
Abstract
Our previous work on angiotensin II-mediated electrical-remodeling in canine left ventricle, in connection with a long history of other studies, suggested the hypothesis: increases in mechanical load induce autocrine secretion of angiotensin II (A2), which coherently regulates a coterie of membrane ion transporters in a manner that increases contractility. However, the relation between load and A2 secretion was correlative. We subsequently showed a similar or identical system was present in murine heart. To investigate whether the relation between mechanical load and A2-mediated electrical remodeling was causal, we employed transverse aortic constriction in mice to subject the left ventricle to pressure overload for short-term (1 to 2 days) or long-term (1 to 2 weeks) periods. Heart-to-body weight ratios and cell capacitance measurements were used to determine hypertrophy. Whole-cell patch clamp recordings of the predominant repolarization currents Ito,fast and IK,slow were used to assess electrical remodeling. Hearts or myocytes subjected to long-term load displayed significant hypertrophy, which was not evident in short-term load. However, short-term load induced significant reductions in Ito,fast and IK,slow. Incubation of these myocytes with the angiotensin II type 1 receptor inhibitor saralasin for 2 hours restored Ito,fast and IK,slow to control levels. The number of Ito.fast or IK,slow channels did not change with A2 or long-term load, however the hypertrophic increase in membrane area reduced the current densities for both channels. For Ito,fast but not IK,slow there was an additional reduction that was reversed by inhibition of angiotensin receptors. These results suggest increased load activates an endogenous renin angiotensin system that initially reduces Ito,fast and IK,slow prior to the onset of hypertrophic growth. However, there are functional interactions between electrical and anatomical remodeling. First, hypertrophy tends to reduce all current densities. Second, the hypertrophic program can modify signaling between the angiotensin receptor and target current.
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Pantazopoulos JS, David A, Kostis WJ, Cosgrove NM, Kostis JB. Cardiovascular outcomes in patients with intraventricular conduction blocks: A sixteen-year follow-up in a state-wide database. Hellenic J Cardiol 2016; 58:194-201. [PMID: 27965025 DOI: 10.1016/j.hjc.2016.11.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 11/14/2016] [Accepted: 11/22/2016] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND To assess the adverse clinical effects of left anterior hemiblock alone or in combination with right bundle branch block and of complete left bundle branch block in comparison with isolated right bundle branch block and the relationship of these effects with altered mechanoelectric factors resulting in left ventricular dysfunction. METHODS In a 16-year follow-up study using a statewide database, we studied the occurrence of mortal and morbid cardiovascular (CV) events among patients without apparent ischemic heart disease who had left anterior hemiblock (LAHB, n=4273, right bundle branch block (RBBB) with LAHB (BFBB, n=1857) and left bundle branch block (LBBB, n=9484 compared to isolated RBBB (n=25288). RESULTS After adjustment for demographics, co-morbidities and insurance, LAHB was associated with a significant excess risk of all-cause death (HR 1.134, 95% CI 1.061-1.213, p=0.0002) and CV death (HR 1.329, 95% CI 1.174-1.501, p<0.0001). BFBB was associated with excess HF (HR 1.190, 95% CI 1.048-1.351, p<0.0071), all-cause death (HR 1.440, 95% CI 1.045-1.252, p=0.0036) and CV death (HR 1.210, 95% CI 1.020-1.436, p<0.0001). LBBB was associated with an excess risk of MR (HR 1.307, 95% CI 1.116-1.530, p<0.0009), HF 1.177, 95% CI1.097-1.263, p<0.0001) and CV death (HR 1.220, 95% CI 1.106-1.345, p<0.0001). CONCLUSIONS In patients without apparent ischemic heart disease, the presence of LAHB alone or in combination with RBBB imparts increased risk of CV and all-cause death compared to isolated RBBB. BFBB is also associated with an increased risk of HF.
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Affiliation(s)
- John S Pantazopoulos
- Cardiovascular Institute, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
| | - Alice David
- Cardiovascular Institute, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - William J Kostis
- Cardiovascular Institute, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Nora M Cosgrove
- Cardiovascular Institute, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - John B Kostis
- Cardiovascular Institute, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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- Cardiovascular Institute, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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Chen Z, Hanson B, Sohal M, Sammut E, Jackson T, Child N, Claridge S, Behar J, Niederer S, Gill J, Carr-White G, Razavi R, Rinaldi CA, Taggart P. Coupling of ventricular action potential duration and local strain patterns during reverse remodeling in responders and nonresponders to cardiac resynchronization therapy. Heart Rhythm 2016; 13:1898-904. [PMID: 27301781 DOI: 10.1016/j.hrthm.2016.06.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Indexed: 10/21/2022]
Abstract
BACKGROUND The high risk of ventricular arrhythmias in patients with heart failure remains despite the benefit of cardiac resynchronization therapy (CRT). An electromechanical interaction between regional myocardial strain patterns and the electrophysiological substrate is thought to be important. OBJECTIVE We investigated the in vivo relation between left ventricular activation recovery interval (ARI), as a surrogate measure of action potential duration (APD), and local myocardial strain patterns in responders and nonresponders to CRT. METHODS ARIs were recorded from the left ventricular epicardium in 20 patients with CRT 6 weeks and 6 months post implantation. Two-dimensional speckle tracking echocardiography was performed at the same time to assess myocardial strains. Patients with ≥15% reduction in end-systolic volume at 6 months were classified as responders. RESULTS ARI decreased in responders (263 ± 46 ms vs 246 ± 47 ms, P < .01) and increased in nonresponders (235 ± 23 ms vs 261 ± 20 ms; P < .01). Time-to-peak radial, circumferential, and longitudinal strains increased in responders (41 ± 27, 35 ± 25, 56 ± 37 ms; P < .01) and decreased in nonresponders (-58 ± 26, -47 ± 26, -64 ± 27 ms; P < .01). There was a nonlinear correlation between changes in time-to-peak strain and ARIs (Spearman correlation coefficient r ≥ 0.70; P < .01). Baseline QRS duration >145 ms and QRS duration shortening with biventricular pacing were associated with ARI shortening following CRT. CONCLUSION Changes in ventricular wall mechanics predict local APD lengthening or shortening during CRT. Nonresponders have a worsening of myocardial strain and local APD. Baseline QRS duration >145 ms and QRS duration shortening with biventricular pacing identified patients who exhibited improvement in APD.
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Affiliation(s)
- Zhong Chen
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom,.
| | - Ben Hanson
- University College London, London, United Kingdom
| | - Manav Sohal
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | - Eva Sammut
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | - Tom Jackson
- King's College London, London, United Kingdom
| | - Nicholas Child
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | - Simon Claridge
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | - Jonathan Behar
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | | | - Jaswinder Gill
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | - Gerald Carr-White
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | - Reza Razavi
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
| | - C Aldo Rinaldi
- King's College London, London, United Kingdom; Guy's and St Thomas' NHS Trust, London, United Kingdom
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Solovyova O, Katsnelson LB, Kohl P, Panfilov AV, Tsaturyan AK, Tsyvian PB. Mechano-electric heterogeneity of the myocardium as a paradigm of its function. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:249-54. [PMID: 26713555 PMCID: PMC4821177 DOI: 10.1016/j.pbiomolbio.2015.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 11/13/2015] [Accepted: 12/16/2015] [Indexed: 01/25/2023]
Abstract
Myocardial heterogeneity is well appreciated and widely documented, from sub-cellular to organ levels. This paper reviews significant achievements of the group, led by Professor Vladimir S. Markhasin, Russia, who was one of the pioneers in studying and interpreting the relevance of cardiac functional heterogeneity.
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Affiliation(s)
- Olga Solovyova
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia; Ural Federal University, Ekaterinburg, Russia.
| | - Leonid B Katsnelson
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia; Ural Federal University, Ekaterinburg, Russia.
| | - Peter Kohl
- Research Centre for Cardiovascular Medicine, University of Freiburg, Germany; National Heart and Lung Institute, Imperial College of London, UK.
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Vikulova NA, Katsnelson LB, Kursanov AG, Solovyova O, Markhasin VS. Mechano-electric feedback in one-dimensional model of myocardium. J Math Biol 2015; 73:335-66. [PMID: 26687545 DOI: 10.1007/s00285-015-0953-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 07/14/2015] [Indexed: 10/22/2022]
Abstract
We utilized our earlier developed 1D mathematical model of the heart muscle strand to study contribution of the bilateral interactions between excitation and contraction on the cellular and tissue levels to the local and global myocardium function. Numerical experiments on the model showed that an initially uniform strand, formed on the inherently identical cells, became functionally heterogeneous due to the asynchronous excitation via the electrical wave spread. Mechanical interactions between the cells and the mechano-electric feedback beat-to-beat affect the functional characteristics of coupled cardiomyocytes further, adjusting their electrical and mechanical heterogeneity to the activation timing. Model simulations showed that functional heterogeneity increases with an enlarged spatial extension of the myocardial strand (in terms of the longer slack length not a higher stretch of the strand), demonstrating a special role of the heart size in its function. Model analysis suggests that cooperative mechanisms of myofilament calcium activation contribute essentially to the generation of cellular functional heterogeneity in contracting cardiac tissue.
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Affiliation(s)
- Nathalie A Vikulova
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia. .,Ural Federal University, Ekaterinburg, Russia.
| | - Leonid B Katsnelson
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
| | - Alexander G Kursanov
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
| | - Olga Solovyova
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
| | - Vladimir S Markhasin
- Laboratory of Mathematical Physiology, Institute of Immunology and Physiology, Ekaterinburg, Russia.,Ural Federal University, Ekaterinburg, Russia
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Chan YH, Tsai WC, Ko JS, Yin D, Chang PC, Rubart M, Weiss JN, Everett TH, Lin SF, Chen PS. Small-Conductance Calcium-Activated Potassium Current Is Activated During Hypokalemia and Masks Short-Term Cardiac Memory Induced by Ventricular Pacing. Circulation 2015; 132:1377-86. [PMID: 26362634 DOI: 10.1161/circulationaha.114.015125] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 06/11/2015] [Indexed: 01/26/2023]
Abstract
BACKGROUND Hypokalemia increases the vulnerability to ventricular fibrillation. We hypothesize that the apamin-sensitive small-conductance calcium-activated potassium current (IKAS) is activated during hypokalemia and that IKAS blockade is proarrhythmic. METHODS AND RESULTS Optical mapping was performed in 23 Langendorff-perfused rabbit ventricles with atrioventricular block and either right or left ventricular pacing during normokalemia or hypokalemia. Apamin prolonged the action potential duration (APD) measured to 80% repolarization (APD80) by 26 milliseconds (95% confidence interval [CI], 14-37) during normokalemia and by 54 milliseconds (95% CI, 40-68) during hypokalemia (P=0.01) at a 1000-millisecond pacing cycle length. In hypokalemic ventricles, apamin increased the maximal slope of APD restitution, the pacing cycle length threshold of APD alternans, the pacing cycle length for wave-break induction, and the area of spatially discordant APD alternans. Apamin significantly facilitated the induction of sustained ventricular fibrillation (from 3 of 9 hearts to 9 of 9 hearts; P=0.009). Short-term cardiac memory was assessed by the slope of APD80 versus activation time. The slope increased from 0.01 (95% CI, -0.09 to 0.12) at baseline to 0.34 (95% CI, 0.23-0.44) after apamin (P<0.001) during right ventricular pacing and from 0.07 (95% CI, -0.05 to 0.20) to 0.54 (95% CI, 0.06-1.03) after apamin infusion (P=0.045) during left ventricular pacing. Patch-clamp studies confirmed increased IKAS in isolated rabbit ventricular myocytes during hypokalemia (P=0.038). CONCLUSIONS Hypokalemia activates IKAS to shorten APD and maintain repolarization reserve at late activation sites during ventricular pacing. IKAS blockade prominently lengthens the APD at late activation sites and facilitates ventricular fibrillation induction.
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Affiliation(s)
- Yi-Hsin Chan
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Wei-Chung Tsai
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Jum-Suk Ko
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Dechun Yin
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Po-Cheng Chang
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Michael Rubart
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - James N Weiss
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Thomas H Everett
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Shien-Fong Lin
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.)
| | - Peng-Sheng Chen
- From Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine (Y.-H.C., W.-C.T., P.-C.C., T.H.E., S.-F.L., P.-S.C.) and Wells Center for Pediatrics Research, Department of Pediatrics (M.R.), Indiana University School of Medicine, Indianapolis; Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, Taoyuan, Taiwan (Y.-H.C., P.-C.C.); Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung University College of Medicine, Taiwan (W.-C.T.); Division of Cardiology, Department of Internal Medicine, Wonkwang University School of Medicine and Hospital, Jeonbuk, Republic of Korea (J.-S.K.); Department of Cardiology, First Affiliated Hospital of Harbin Medical University, China (D.Y.); Departments of Medicine (Cardiology) and Physiology, University of California, Los Angeles (J.N.W.); and Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan (S.-F.L.).
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Faggioni M, Knollmann BC. Arrhythmia Protection in Hypokalemia: A Novel Role of Ca2+-Activated K+ Currents in the Ventricle. Circulation 2015; 132:1371-3. [PMID: 26362635 DOI: 10.1161/circulationaha.115.018874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Michela Faggioni
- From Division of Cardiovascular Medicine, Cardio-Thoracic and Vascular Department, University of Pisa, Italy (M.F.); and Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN (B.C.K.)
| | - Björn C Knollmann
- From Division of Cardiovascular Medicine, Cardio-Thoracic and Vascular Department, University of Pisa, Italy (M.F.); and Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN (B.C.K.).
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Floré V, Bartunek J, Goethals M, Verstreken S, Timmermans W, De Pauw F, Van Bockstal K, Vanderheyden M. Electrical remodeling reflected by QRS and T vector changes following cardiac resynchronization therapy is related to survival in heart failure patients with left bundle branch block. J Electrocardiol 2015; 48:578-85. [DOI: 10.1016/j.jelectrocard.2015.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Indexed: 12/01/2022]
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Perrotta L, Ricciardi G, Pieragnoli P, Nesti M, Pontecorboli G, Fantini F, Padeletti L. Cardiac memory in cardiac resynchronization therapy: A vectorcardiographic comparison of biventricular and left ventricular pacing. J Electrocardiol 2015; 48:571-7. [PMID: 25987410 DOI: 10.1016/j.jelectrocard.2015.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Indexed: 11/26/2022]
Abstract
INTRODUCTION "Cardiac memory" (CM) refers to a change in repolarization induced by an altered pathway of activation, manifested after resumption of spontaneous ventricular activation (SVA). AIMS To investigate for the first time in humans the effects of left ventricular (LV) pacing on CM development through vectorcardiography (VCG). METHODS We studied 28 patients with heart failure (HF) and left bundle branch block (LBBB) treated with cardiac resynchronization therapy (CRT). Fourteen patients underwent biventricular (BIV) stimulation; the other 14 underwent LV stimulation only. VCG was acquired during SVA at baseline and during AAI and DDD pacing immediately after and 7 and 90 days after the implant. RESULTS At baseline, in both groups, the QRS and T vectors angles were those specific of LBBB pattern. During DDD pacing, QRS vector angle changed to the right and upward in BIV patients while no significant differences were observed in LV patients. During AAI pacing, T vector angle changed significantly in BIV patients, following the direction of the paced QRS and amplitude significantly increased. In LV patients no significant differences in T vector angles were observed. Only T vector amplitude significantly increased at 7 days (p=0.03) and at 90 days (p=0.008 vs baseline). CONCLUSION In patients with LBBB, BIV pacing induces cardiac memory development as a significant change in T vector magnitude and angle, while LV pacing doesn't induce significant modifications in QRS and T vector angles and CM is manifested only as a significant T vector amplitude change.
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Affiliation(s)
- Alexei Shvilkin
- From the Department of Medicine/Cardiology Division, Beth Israel Deaconess Medical Center, Boston, MA
| | - Henry D. Huang
- From the Department of Medicine/Cardiology Division, Beth Israel Deaconess Medical Center, Boston, MA
| | - Mark E. Josephson
- From the Department of Medicine/Cardiology Division, Beth Israel Deaconess Medical Center, Boston, MA
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Perspective: a dynamics-based classification of ventricular arrhythmias. J Mol Cell Cardiol 2015; 82:136-52. [PMID: 25769672 DOI: 10.1016/j.yjmcc.2015.02.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/05/2015] [Accepted: 02/20/2015] [Indexed: 02/04/2023]
Abstract
Despite key advances in the clinical management of life-threatening ventricular arrhythmias, culminating with the development of implantable cardioverter-defibrillators and catheter ablation techniques, pharmacologic/biologic therapeutics have lagged behind. The fundamental issue is that biological targets are molecular factors. Diseases, however, represent emergent properties at the scale of the organism that result from dynamic interactions between multiple constantly changing molecular factors. For a pharmacologic/biologic therapy to be effective, it must target the dynamic processes that underlie the disease. Here we propose a classification of ventricular arrhythmias that is based on our current understanding of the dynamics occurring at the subcellular, cellular, tissue and organism scales, which cause arrhythmias by simultaneously generating arrhythmia triggers and exacerbating tissue vulnerability. The goal is to create a framework that systematically links these key dynamic factors together with fixed factors (structural and electrophysiological heterogeneity) synergistically promoting electrical dispersion and increased arrhythmia risk to molecular factors that can serve as biological targets. We classify ventricular arrhythmias into three primary dynamic categories related generally to unstable Ca cycling, reduced repolarization, and excess repolarization, respectively. The clinical syndromes, arrhythmia mechanisms, dynamic factors and what is known about their molecular counterparts are discussed. Based on this framework, we propose a computational-experimental strategy for exploring the links between molecular factors, fixed factors and dynamic factors that underlie life-threatening ventricular arrhythmias. The ultimate objective is to facilitate drug development by creating an in silico platform to evaluate and predict comprehensively how molecular interventions affect not only a single targeted arrhythmia, but all primary arrhythmia dynamics categories as well as normal cardiac excitation-contraction coupling.
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Solovyova O, Katsnelson LB, Konovalov PV, Kursanov AG, Vikulova NA, Kohl P, Markhasin VS. The cardiac muscle duplex as a method to study myocardial heterogeneity. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:115-28. [PMID: 25106702 PMCID: PMC4210666 DOI: 10.1016/j.pbiomolbio.2014.07.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 07/25/2014] [Indexed: 12/14/2022]
Abstract
This paper reviews the development and application of paired muscle preparations, called duplex, for the investigation of mechanisms and consequences of intra-myocardial electro-mechanical heterogeneity. We illustrate the utility of the underlying combined experimental and computational approach for conceptual development and integration of basic science insight with clinically relevant settings, using previously published and new data. Directions for further study are identified.
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Affiliation(s)
- O Solovyova
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia; Ural Federal University, 19 Mira Str, Ekaterinburg 620002, Russia.
| | - L B Katsnelson
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia
| | - P V Konovalov
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia
| | - A G Kursanov
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia; Ural Federal University, 19 Mira Str, Ekaterinburg 620002, Russia
| | - N A Vikulova
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia
| | - P Kohl
- National Heart and Lung Institute, Imperial College of London, Heart Science Centre, Harefield Hospital, Hill End Road, Harefield UB9 6JH, UK; Department of Computer Sciences, University of Oxford, UK
| | - V S Markhasin
- Institute of Immunology and Physiology, Ural Branch of the Russian Academy of Sciences, 106 Pervomayskaya Str, Ekaterinburg 620049, Russia; Ural Federal University, 19 Mira Str, Ekaterinburg 620002, Russia
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Kuijpers NHL, Hermeling E, Lumens J, ten Eikelder HMM, Delhaas T, Prinzen FW. Mechano-electrical coupling as framework for understanding functional remodeling during LBBB and CRT. Am J Physiol Heart Circ Physiol 2014; 306:H1644-59. [DOI: 10.1152/ajpheart.00689.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is not understood why, after onset of left bundle-branch block (LBBB), acute worsening of cardiac function is followed by a further gradual deterioration of function, whereas most adverse cardiac events lead to compensatory adaptations. We investigated whether mechano-electrical coupling (MEC) can explain long-term remodeling with LBBB and cardiac resynchronization therapy (CRT). To this purpose, we used an integrative modeling approach relating local ventricular electrophysiology, calcium handling, and excitation-contraction coupling to global cardiovascular mechanics and hemodynamics. Each ventricular wall was composed of multiple mechanically and electrically coupled myocardial segments. MEC was incorporated by allowing adaptation of L-type Ca2+ current aiming at minimal dispersion of local external work, an approach that we previously applied to replicate T-wave memory in a synchronous heart after a period of asynchronous activation. LBBB instantaneously decreased left-ventricular stroke work and increased end-diastolic volume. During sustained LBBB, MEC reduced intraventricular dispersion of mechanical workload and repolarization. However, MEC-induced reduction in contractility in late-activated regions was larger than the contractility increase in early-activated regions, resulting in further decrease of stroke work and increase of end-diastolic volume. Upon the start of CRT, stroke work increased despite a wider dispersion of mechanical workload. During sustained CRT, MEC-induced reduction in dispersion of workload and repolarization coincided with a further reduction in end-diastolic volume. In conclusion, MEC may represent a useful framework for better understanding the long-term changes in cardiac electrophysiology and contraction following LBBB as well as CRT.
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Affiliation(s)
- Nico H. L. Kuijpers
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Evelien Hermeling
- Department of Radiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Joost Lumens
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Huub M. M. ten Eikelder
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Tammo Delhaas
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Frits W. Prinzen
- Department of Physiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
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Hu Y, Gurev V, Constantino J, Trayanova N. Optimizing cardiac resynchronization therapy to minimize ATP consumption heterogeneity throughout the left ventricle: a simulation analysis using a canine heart failure model. Heart Rhythm 2014; 11:1063-9. [PMID: 24657430 PMCID: PMC4049272 DOI: 10.1016/j.hrthm.2014.03.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Indexed: 12/29/2022]
Abstract
BACKGROUND Cardiac resynchronization therapy (CRT) has been demonstrated to lead to restoration of oxygen consumption homogeneity throughout the left ventricle (LV), which is important for long-term reverse remodeling of the ventricles. However, research has focused exclusively on identifying the LV pacing sites that led to acute hemodynamic improvements. It remains unclear whether there exist LV pacing sites that could both improve the hemodynamics and result in ATP consumption homogeneity throughout the LV, thus maximizing both CRT short-term and long-term benefits. OBJECTIVE The purpose of this study was to demonstrate the feasibility of optimizing CRT pacing locations to achieve maximal improvement in both ATPCTHI (an ATP consumption heterogeneity index) and stroke work. METHODS We used an magnetic resonance image-based electromechanical model of the dyssynchronous heart failure (DHF) canine ventricles. ATPCTHI and stroke work improvement were determined for each of 34 CRT pacing sites evenly spaced over the LV epicardium. RESULTS Results demonstrated the feasibility of determining the optimal LV pacing site that achieves simultaneous maximum improvements in ATPCTHI and stroke work. The optimal LV CRT pacing sites in the DHF canine ventricles were located midway between apex and base. The improvement in ATPCTHI decreased more rapidly with the distance from the optimal sites compared to stroke work improvement. CRT from the optimal sites homogenized ATP consumption by increasing septal ATP consumption and decreasing that of the lateral wall. CONCLUSION Simulation results using a canine heart failure model demonstrated that CRT can be optimized to achieve improvements in both ATPCTHI and stroke work.
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Affiliation(s)
- Yuxuan Hu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Viatcheslav Gurev
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Jason Constantino
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Natalia Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland.
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The importance of non-uniformities in mechano-electric coupling for ventricular arrhythmias. J Interv Card Electrophysiol 2013; 39:25-35. [DOI: 10.1007/s10840-013-9852-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 10/16/2013] [Indexed: 12/31/2022]
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MANNE MAHESH, RICKARD JOHN, VARMA NIRAJ, CHUNG MINAK, TCHOU PATRICK. Normalization of Left Ventricular Ejection Fraction after Cardiac Resynchronization Therapy Also Normalizes Survival. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2013; 36:970-7. [DOI: 10.1111/pace.12174] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 03/03/2013] [Accepted: 04/02/2013] [Indexed: 11/27/2022]
Affiliation(s)
- MAHESH MANNE
- Department of Internal Medicine; Cleveland Clinic; Cleveland; Ohio
| | - JOHN RICKARD
- Division of Cardiology; Johns Hopkins Bayview Medical Center; Baltimore; Maryland
| | - NIRAJ VARMA
- Department of Cardiovascular Medicine; Heart and Vascular Institute; Cleveland Clinic; Cleveland; Ohio
| | - MINA K. CHUNG
- Department of Cardiovascular Medicine; Heart and Vascular Institute; Cleveland Clinic; Cleveland; Ohio
| | - PATRICK TCHOU
- Department of Cardiovascular Medicine; Heart and Vascular Institute; Cleveland Clinic; Cleveland; Ohio
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Jeyaraj D, Wan X, Ficker E, Stelzer JE, Deschenes I, Liu H, Wilson LD, Decker KF, Said TH, Jain MK, Rudy Y, Rosenbaum DS. Ionic bases for electrical remodeling of the canine cardiac ventricle. Am J Physiol Heart Circ Physiol 2013; 305:H410-9. [PMID: 23709598 DOI: 10.1152/ajpheart.00213.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Emerging evidence suggests that ventricular electrical remodeling (VER) is triggered by regional myocardial strain via mechanoelectrical feedback mechanisms; however, the ionic mechanisms underlying strain-induced VER are poorly understood. To determine its ionic basis, VER induced by altered electrical activation in dogs undergoing left ventricular pacing (n = 6) were compared with unpaced controls (n = 4). Action potential (AP) durations (APDs), ionic currents, and Ca(2+) transients were measured from canine epicardial myocytes isolated from early-activated (low strain) and late-activated (high strain) left ventricular regions. VER in the early-activated region was characterized by minimal APD prolongation, but marked attenuation of the AP phase 1 notch attributed to reduced transient outward K(+) current. In contrast, VER in the late-activated region was characterized by significant APD prolongation. Despite marked APD prolongation, there was surprisingly minimal change in ion channel densities but a twofold increase in diastolic Ca(2+). Computer simulations demonstrated that changes in sarcolemmal ion channel density could only account for attenuation of the AP notch observed in the early-activated region but failed to account for APD remodeling in the late-activated region. Furthermore, these simulations identified that cytosolic Ca(2+) accounted for APD prolongation in the late-activated region by enhancing forward-mode Na(+)/Ca(2+) exchanger activity, corroborated by increased Na(+)/Ca(2+) exchanger protein expression. Finally, assessment of skinned fibers after VER identified altered myofilament Ca(2+) sensitivity in late-activated regions to be associated with increased diastolic levels of Ca(2+). In conclusion, we identified two distinct ionic mechanisms that underlie VER: 1) strain-independent changes in early-activated regions due to remodeling of sarcolemmal ion channels with no changes in Ca(2+) handling and 2) a novel and unexpected mechanism for strain-induced VER in late-activated regions in the canine arising from remodeling of sarcomeric Ca(2+) handling rather than sarcolemmal ion channels.
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Affiliation(s)
- Darwin Jeyaraj
- The Heart and Vascular Research Center and Department of Biomedical Engineering, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109, USA.
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Kerckhoffs RCP, Omens JH, McCulloch AD. Mechanical discoordination increases continuously after the onset of left bundle branch block despite constant electrical dyssynchrony in a computational model of cardiac electromechanics and growth. Europace 2013; 14 Suppl 5:v65-v72. [PMID: 23104917 DOI: 10.1093/europace/eus274] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
AIMS To test whether a functional growth law leads to asymmetric hypertrophy and associated changes in global and regional cardiac function when integrated with a computational model of left bundle branch block (LBBB). METHODS AND RESULTS In recent studies, we proposed that cardiac myocytes grow longer when a threshold of maximum fibre strain is exceeded and grow thicker when the smallest maximum principal strain in the cellular cross-sectional plane exceeds a threshold. A non-linear cardiovascular model of the beating canine ventricles was combined with the cellular growth law. After inducing LBBB, the ventricles were allowed to adapt in shape over time in response to mechanical stimuli. When subjected to electrical dyssynchrony, the combined model of ventricular electromechanics, haemodynamics, and growth led to asymmetric hypertrophy with a faster increase of wall mass in the left ventricular (LV) free wall (FW) than the septum, increased LV end-diastolic and end-systolic volumes, and decreased LV ejection fraction. Systolic LV pressure decreased during the acute phase of LBBB and increased at later stages. The relative changes of these parameters were similar to those obtained experimentally. Most of the dilation was due to radial and axial fibre growth, and hence altered shape of the LVFW. CONCLUSION Our previously proposed growth law reproduced measured dyssynchronously induced asymmetric hypertrophy and the associated functional changes, when combined with a computational model of the LBBB heart. The onset of LBBB leads to a step increase in LV mechanical discoordination that continues to increase as the heart remodels despite the constant electrical dyssynchrony.
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Affiliation(s)
- Roy C P Kerckhoffs
- Department of Bioengineering, Institute of Engineering in Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA.
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Chen Z, Hanson B, Sohal M, Sammut E, Child N, Shetty A, Boucher R, Bostock J, Gill J, Carr-White G, Rinaldi CA, Taggart P. Left Ventricular Epicardial Electrograms Show Divergent Changes in Action Potential Duration in Responders and Nonresponders to Cardiac Resynchronization Therapy. Circ Arrhythm Electrophysiol 2013; 6:265-71. [DOI: 10.1161/circep.112.000148] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Zhong Chen
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Ben Hanson
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Manav Sohal
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Eva Sammut
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Nick Child
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Anoop Shetty
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Ryan Boucher
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Julian Bostock
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Jaswinder Gill
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Gerald Carr-White
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - C. Aldo Rinaldi
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
| | - Peter Taggart
- From the Kings College London, London, United kingdom (Z.C., M.S., E.S., N.C., A.S., J.B., J.G., G.C.-W., C.A.R.); University College London, London, United Kingdom (B.H., P.T.); and St. Jude Medical, Stratford Upon Avon, United Kingdom (R.B.)
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Markhasin VS, Balakin AA, Katsnelson LB, Konovalov P, Lookin ON, Protsenko Y, Solovyova O. Slow force response and auto-regulation of contractility in heterogeneous myocardium. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:305-18. [DOI: 10.1016/j.pbiomolbio.2012.08.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 08/09/2012] [Indexed: 11/25/2022]
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Hermeling E, Delhaas T, Prinzen FW, Kuijpers NHL. Mechano-electrical feedback explains T-wave morphology and optimizes cardiac pump function: insight from a multi-scale model. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:359-71. [PMID: 22835663 DOI: 10.1016/j.pbiomolbio.2012.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 11/17/2022]
Abstract
In the ECG, T- and R-wave are concordant during normal sinus rhythm (SR), but discordant after a period of ventricular pacing (VP). Experiments showed that the latter phenomenon, called T-wave memory, is mediated by a mechanical stimulus. By means of a mathematical model, we investigated the hypothesis that slow acting mechano-electrical feedback (MEF) explains T-wave memory. In our model, electromechanical behavior of the left ventricle (LV) was simulated using a series of mechanically and electrically coupled segments. Each segment comprised ionic membrane currents, calcium handling, and excitation-contraction coupling. MEF was incorporated by locally adjusting conductivity of L-type calcium current (g(CaL)) to local external work. In our set-up, g(CaL) could vary up to 25%, 50%, 100% or unlimited amount around its default value. Four consecutive simulations were performed: normal SR (with MEF), acute VP, sustained VP (with MEF), and acutely restored SR. MEF led to T-wave concordance in normal SR and to discordant T-waves acutely after restoring SR. Simulated ECGs with a maximum of 25-50% adaptation closely resembled those during T-wave memory experiments in vivo and also provided the best compromise between optimal systolic and diastolic function. In conclusion, these simulation results indicate that slow acting MEF in the LV can explain a) the relatively small differences in systolic shortening and mechanical work during SR, b) the small dispersion in repolarization time, c) the concordant T-wave during SR, and d) T-wave memory. The physiological distribution in electrophysiological properties, reflected by the concordant T-wave, may serve to optimize cardiac pump function.
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Affiliation(s)
- Evelien Hermeling
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands.
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The zebrafish as a novel animal model to study the molecular mechanisms of mechano-electrical feedback in the heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:154-65. [PMID: 22835662 DOI: 10.1016/j.pbiomolbio.2012.07.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 07/16/2012] [Indexed: 02/07/2023]
Abstract
Altered mechanical loading of the heart leads to hypertrophy, decompensated heart failure and fatal arrhythmias. However, the molecular mechanisms that link mechanical and electrical dysfunction remain poorly understood. Growing evidence suggest that ventricular electrical remodeling (VER) is a process that can be induced by altered mechanical stress, creating persistent electrophysiological changes that predispose the heart to life-threatening arrhythmias. While VER is clearly a physiological property of the human heart, as evidenced by "T wave memory", it is also thought to occur in a variety of pathological states associated with altered ventricular activation such as bundle branch block, myocardial infarction, and cardiac pacing. Animal models that are currently being used for investigating stretch-induced VER have significant limitations. The zebrafish has recently emerged as an attractive animal model for studying cardiovascular disease and could overcome some of these limitations. Owing to its extensively sequenced genome, high conservation of gene function, and the comprehensive genetic resources that are available in this model, the zebrafish may provide new insights into the molecular mechanisms that drive detrimental electrical remodeling in response to stretch. Here, we have established a zebrafish model to study mechano-electrical feedback in the heart, which combines efficient genetic manipulation with high-precision stretch and high-resolution electrophysiology. In this model, only 90 min of ventricular stretch caused VER and recapitulated key features of VER found previously in the mammalian heart. Our data suggest that the zebrafish model is a powerful platform for investigating the molecular mechanisms underlying mechano-electrical feedback and VER in the heart.
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Marrus SB, Andrews CM, Cooper DH, Faddis MN, Rudy Y. Repolarization changes underlying long-term cardiac memory due to right ventricular pacing: noninvasive mapping with electrocardiographic imaging. Circ Arrhythm Electrophysiol 2012; 5:773-81. [PMID: 22772896 DOI: 10.1161/circep.112.970491] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Cardiac memory refers to the observation that altered cardiac electrical activation results in repolarization changes that persist after the restoration of a normal activation pattern. Animal studies, however, have yielded disparate conclusions, both regarding the spatial pattern of repolarization changes in cardiac memory and the underlying mechanisms. The present study was undertaken to produce 3-dimensional images of the repolarization changes underlying long-term cardiac memory in humans. METHODS AND RESULTS Nine adult subjects with structurally normal hearts and dual-chamber pacemakers were enrolled in the study. Noninvasive electrocardiographic imaging was used before and after 1 month of ventricular pacing to reconstruct epicardial activation and repolarization patterns. Eight subjects exhibited cardiac memory in response to ventricular pacing. In all subjects, ventricular pacing resulted in a prolongation of the activation recovery interval (a surrogate for action potential duration) in the region close to the site of pacemaker-induced activation from 228.4±7.6 ms during sinus rhythm to 328.3±6.2 ms during cardiac memory. As a consequence, increases are observed in both apical-basal and right-left ventricular gradients of repolarization, resulting in a significant increase in the dispersion of repolarization. CONCLUSIONS These results demonstrate that electrical remodeling in response to ventricular pacing in human subjects results in action potential prolongation near the site of abnormal activation and a marked dispersion of repolarization. This dispersion of repolarization is potentially arrhythmogenic and, intriguingly, was less evident during continuous right ventricular pacing, suggesting the novel possibility that continuous right ventricular pacing at least partially suppresses pacemaker-induced cardiac memory.
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Affiliation(s)
- Scott B Marrus
- Cardiovascular Division, Washington University School of Medicine, St. Louis, MO, USA
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