1
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Duras E, Sulu A, Kafali HC, Sisko SG, Caran B, Ergul Y. Evaluation of T-wave memory after accessory pathway ablation in pediatric patients with Wolff-Parkinson-White syndrome. Pacing Clin Electrophysiol 2024. [PMID: 38742589 DOI: 10.1111/pace.14997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/29/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024]
Abstract
BACKGROUND T-wave memory (TWM) is a rare cause of T-wave inversion (TWI). Alterations in ventricular activation due to abnormal depolarization may cause repolarization abnormalities on the ECG, even if myocardial conduction returns to normal. These repolarization changes are defined as TWM. In our study, we aimed to determine the frequency of TWM development and the predictors affecting it in the pediatric population who underwent accessory pathway (AP) ablation due to Wolff-Parkinson-White (WPW) syndrome. METHODS The data of patients with manifest AP who underwent electrophysiological studies and ablation between 2015 and 2021 were retrospectively analyzed. The study included 180 patients who were under 21 years of age and had at least one year of follow-up after ablation. Patients with structural heart disease, intermittent WPWs, recurrent ablation, other arrhythmia substrates, and those with less than one-year follow-up were excluded from the study. The ECG data of the patients before the procedure, in the first 24 h after the procedure, three months, and in the first year were recorded. The standard ablation technique was used in all patients. RESULTS Postprocedure TWM was observed in 116 (64.4%) patients. Ninety-three patients (51.7%) had a right-sided AP, and 87 patients (48.3%) had a left-sided AP. The presence of posteroseptal AP was found to be significantly higher in the group that developed TWM. Of these patients, 107 (93.1%) patients showed improvement at the end of the first year. Preprocedural absolute QRS-T angle, postprocedural PR interval, and right posteroseptal pathway location were identified as predictors of TWM. CONCLUSION The development of TWM is particularly associated with the right-sided pathway location, especially the right posteroseptal pathway location. The predictors of TWM are the preprocedural QRS-T angle, the postprocedural PR interval, and the presence of the right posteroseptal AP.
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Affiliation(s)
- Ensar Duras
- Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Center, Department of Pediatric Cardiology, University of Health Sciences, Istanbul, Turkey
| | - Ayse Sulu
- Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Center, Department of Pediatric Cardiology, University of Health Sciences, Istanbul, Turkey
| | - Hasan Candas Kafali
- Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Center, Department of Pediatric Cardiology, University of Health Sciences, Istanbul, Turkey
| | - Sezen Gulumser Sisko
- Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Center, Department of Pediatric Cardiology, University of Health Sciences, Istanbul, Turkey
| | - Bahar Caran
- Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Center, Department of Pediatric Cardiology, University of Health Sciences, Istanbul, Turkey
| | - Yakup Ergul
- Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Center, Department of Pediatric Cardiology, University of Health Sciences, Istanbul, Turkey
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2
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Wang X, Landaw J, Qu Z. Intracellular ion accumulation in the genesis of complex action potential dynamics under cardiac diseases. Phys Rev E 2024; 109:024410. [PMID: 38491656 DOI: 10.1103/physreve.109.024410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/19/2024] [Indexed: 03/18/2024]
Abstract
Intracellular ions, including sodium (Na^{+}), calcium (Ca^{2+}), and potassium (K^{+}), etc., accumulate slowly after a change of the state of the heart, such as a change of the heart rate. The goal of this study is to understand the roles of slow ion accumulation in the genesis of cardiac memory and complex action-potential duration (APD) dynamics that can lead to lethal cardiac arrhythmias. We carry out numerical simulations of a detailed action potential model of ventricular myocytes under normal and diseased conditions, which exhibit memory effects and complex APD dynamics. We develop a low-dimensional iterated map (IM) model to describe the dynamics of Na^{+}, Ca^{2+}, and APD and use it to uncover the underlying dynamical mechanisms. The development of the IM model is informed by simulation results under the normal condition. We then use the IM model to perform linear stability analyses and computer simulations to investigate the bifurcations and complex APD dynamics, which depend on the feedback loops between APD and intracellular Ca^{2+} and Na^{+} concentrations and the steepness of the APD response to the ion concentrations. When the feedback between APD and Ca^{2+} concentration is positive, a Hopf bifurcation leading to periodic oscillatory behavior occurs as the steepness of the APD response to the ion concentrations increases. The negative feedback loop between APD and Na^{+} concentration is required for the Hopf bifurcation. When the feedback between APD and Ca^{2+} concentration is negative, period-doubling bifurcations leading to high periodicity and chaos occurs. In this case, Na^{+} accumulation plays little role in the dynamics. Finally, we carry out simulations of the detailed action potential model under two diseased conditions, which exhibit steep APD responses to ion concentrations. Under both conditions, Hopf bifurcations leading to slow oscillations or period-doubling bifurcations leading to high periodicity and chaotic APD dynamics occur, depending on the strength of the ion pump-Na^{+}-Ca^{2+} exchanger. Using functions reconstructed from the simulation data, the IM model accurately captures the bifurcations and dynamics under the two diseased conditions. In conclusion, besides using computer simulations of a detailed high-dimensional action-potential model to investigate the effects of slow ion accumulation and short-term memory on bifurcations and genesis of complex APD dynamics in cardiac myocytes under diseased conditions, this study also provides a low-dimensional mathematical tool, i.e., the IM model, to allow stability analyses for uncovering the underlying mechanisms.
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Affiliation(s)
- Xinyu Wang
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Julian Landaw
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Zhilin Qu
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
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3
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Al-Owais MM, Hettiarachchi NT, Dallas ML, Scragg JL, Lippiat JD, Holden AV, Steele DS, Peers C. Inhibition of the voltage-gated potassium channel Kv1.5 by hydrogen sulfide attenuates remodeling through S-nitrosylation-mediated signaling. Commun Biol 2023; 6:651. [PMID: 37336943 PMCID: PMC10279668 DOI: 10.1038/s42003-023-05016-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 06/05/2023] [Indexed: 06/21/2023] Open
Abstract
The voltage-gated K+ channel plays a key role in atrial excitability, conducting the ultra-rapid rectifier K+ current (IKur) and contributing to the repolarization of the atrial action potential. In this study, we examine its regulation by hydrogen sulfide (H2S) in HL-1 cardiomyocytes and in HEK293 cells expressing human Kv1.5. Pacing induced remodeling resulted in shorting action potential duration, enhanced both Kv1.5 channel and H2S producing enzymes protein expression in HL-1 cardiomyocytes. H2S supplementation reduced these remodeling changes and restored action potential duration through inhibition of Kv1.5 channel. H2S also inhibited recombinant hKv1.5, lead to nitric oxide (NO) mediated S-nitrosylation and activated endothelial nitric oxide synthase (eNOS) by increased phosphorylation of Ser1177, prevention of NO formation precluded these effects. Regulation of Ikur by H2S has important cardiovascular implications and represents a novel and potential therapeutic target.
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Affiliation(s)
- Moza M Al-Owais
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - Nishani T Hettiarachchi
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
| | - Mark L Dallas
- Reading School of Pharmacy, University of Reading, Reading, RG6 6UB, UK
| | - Jason L Scragg
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Arun V Holden
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Derek S Steele
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Chris Peers
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
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4
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Abstract
Cardiac memory is the term used to describe an interesting electrocardiographic phenomenon. Whenever a QRS complex is wide and abnormal, such as during ventricular pacing, the T waves will also be abnormal and will point to the opposite direction of the wide QRS. If the QRS then normalizes, such as after cessation of ventricular pacing, the T waves will normalize as well, but at a later stage. The period of cardiac memory is the phase between the sudden normalization of the QRS and the eventual and gradual return of the T waves to their baseline morphology. Cardiac memory is assumed to be an innocent electrocardiographic curiosity. However, during cardiac memory, reduction of repolarizing potassium currents increases left ventricular repolarization gradients. Therefore, when cardiac memory occurs in patients who already have a prolonged QT interval (for whatever reason), it can lead to a frank long QT syndrome with QT-related ventricular arrhythmias (torsades de pointes). These arrhythmogenic effects of cardiac memory are not generally appreciated and are reviewed here for the first time.
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Affiliation(s)
- Sami Viskin
- Department of Cardiology, Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Israel (S.V., E.C., A.L.S., R.R.)
| | - Ehud Chorin
- Department of Cardiology, Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Israel (S.V., E.C., A.L.S., R.R.)
| | - Arie Lorin Schwartz
- Department of Cardiology, Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Israel (S.V., E.C., A.L.S., R.R.)
| | - Piotr Kukla
- Department of Internal Medicine and Cardiology, Specialistic Hospital, Gorlice, Poland (P.K.)
| | - Raphael Rosso
- Department of Cardiology, Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Israel (S.V., E.C., A.L.S., R.R.)
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5
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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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6
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Haq KT, Javadekar N, Tereshchenko LG. Detection and removal of pacing artifacts prior to automated analysis of 12-lead ECG. Comput Biol Med 2021; 133:104396. [PMID: 33872969 DOI: 10.1016/j.compbiomed.2021.104396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Pacing artifacts must be excluded from the analysis of paced ECG waveform. This study aimed to develop and validate an algorithm to identify and remove the pacing artifacts on ECG and vectorcardiogram (VCG). METHODS We developed a semi-automatic algorithm that identifies the onset and offset of a pacing artifact based on the VCG signal slope steepness and designed a graphical user interface that permits quality control and fine-tuning the constraining threshold values. We used 1054 ECGs from the retrospective, multicenter cohort study "Global Electrical Heterogeneity and Clinical Outcomes," including 3825 atrial and 10,031 ventricular pacing artifacts for the algorithm development and 22 ECGs including 108 atrial and 241 ventricular pacing artifacts for validation. Validation was performed per digital sample. We used the kappa-statistic of interrater agreement between manually labeled sample (ground-truth) and automated detection. RESULTS The constraining parameter values were for onset threshold 13.06 ± 6.21 μV/ms, offset threshold 34.77 ± 17.80 μV/ms, and maximum window size 27.23 ± 3.53 ms. The automated algorithm detected a digital sample belonging to pacing artifact with a sensitivity of 74.5% and specificity of 99.6% and classified correctly 98.8% of digital samples (ROC AUC 0.871; 95%CI 0.853-0.878). The kappa-statistic was 0.785, indicating substantial agreement. The agreement was on 98.81% digital samples, significantly (P < 0.00001) larger than the random agreement on 94.43% of digital samples. CONCLUSIONS The semi-automated algorithm can detect and remove ECG pacing artifacts with high accuracy and provide a user-friendly interface for quality control.
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Affiliation(s)
- Kazi T Haq
- Oregon Health & Science University, Knight Cardiovascular Institute, Portland, OR, USA
| | - Neeraj Javadekar
- Oregon Health & Science University, Knight Cardiovascular Institute, Portland, OR, USA
| | - Larisa G Tereshchenko
- Oregon Health & Science University, Knight Cardiovascular Institute, Portland, OR, USA.
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7
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Haq KT, Cao J, Tereshchenko LG. Characteristics of Cardiac Memory in Patients with Implanted Cardioverter-defibrillators: The Cardiac Memory with Implantable Cardioverter-defibrillator (CAMI) Study. J Innov Card Rhythm Manag 2021; 12:4395-4408. [PMID: 33654571 PMCID: PMC7909362 DOI: 10.19102/icrm.2021.120204] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/12/2020] [Indexed: 01/12/2023] Open
Abstract
This study sought to determine factors associated with cardiac memory (CM) in patients with implantable cardioverter-defibrillators (ICDs). Patients with structural heart disease [n = 20; mean age: 72.6 ± 11.6 years; 80% male; mean left ventricular ejection fraction (LVEF): 31.7 ± 7.6%; history of myocardial infarction in 75% and nonsustained ventricular tachycardia (NSVT) in 85%] and preserved atrioventricular conduction received dual-chamber ICDs for primary (80%) or secondary (20%) prevention. Standard 12-lead electrocardiograms were recorded in AAI and DDD modes before and after seven days of right ventricular (RV) pacing in DDD mode with a short atrioventricular delay. The direction (azimuth and elevation) and magnitude of spatial QRS, T, and spatial ventricular gradient vectors were measured before and after seven days of RV pacing. CM was quantified as the degree of alignment between QRSDDD-7 and TAAI-7 vectors (QRSDDD-7 –TAAI-7 angle). Circular statistics and mixed models with a random slope and intercept were adjusted for changes in cardiac activation, LVEF, known risk factors, and the use of medications known to affect CM occurring on days 1 through 7. The QRSDDD-7–TAAI-7 angle strongly correlated (circular r = −0.972; p < 0.0001) with a TAAI-7–TDDD-7 angle. In the mixed models, CM-T azimuth changes [+132° (95% confidence interval (CI): 80°–184°); p < 0.0001] were counteracted by the history of MI [−180° (95% CI: −320° to −40°); p = 0.011] and female sex [−162° (95% CI: −268° to −55°); p = 0.003]. A CM-T area increase [+15 (95% CI: 6–24) mV*ms; p < 0.0001] was amplified by NSVT history [+27 (95% CI: 4–46) mV*ms; p = 0.007]. These findings suggest that preexistent electrical remodeling affects CM in response to RV pacing, that CM exhibits saturation behavior, and that women reach CM saturation more easily than men.
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Affiliation(s)
- Kazi T Haq
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
| | - Jian Cao
- Medtronic, Inc., Minneapolis, MN, USA
| | - Larisa G Tereshchenko
- Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
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8
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Pierce JB, Rosenthal J, Stone NJ. Worth Remembering: Cardiac Memory Presenting as Deep Anterior T-Wave Inversions Explained by Intermittent Left Bundle Branch Block. Am J Cardiol 2020; 135:174-176. [PMID: 32866450 DOI: 10.1016/j.amjcard.2020.08.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 10/23/2022]
Abstract
Cardiac memory is a common cause of deep T-wave inversions (TWI) in the anterior precordial leads and can be difficult to distinguish from alternative causes of TWI such as myocardial ischemia. Cardiac memory is generally a benign condition except in the setting of prolonged QT when it can contribute to the precipitation of torsades de pointes. Herein, we describe the presentation and clinical course of a case of cardiac memory due to intermittent left bundle branch block (LBBB) that presented asymptomatically to our outpatient cardiology clinic with deep anterior TWI. We discuss common causes of and mechanisms underlying cardiac memory and how to distinguish it from alternative causes of TWI based on 12-lead electrocardiogram. In conclusion, intermittent LBBB is an under-recognized cause of cardiac memory that can present as deep anterior TWI mimicking cardiac ischemia, and awareness of this clinical entity may help prevent unnecessary invasive and expensive testing on otherwise healthy patients.
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Affiliation(s)
- Jacob B Pierce
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - James Rosenthal
- Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; Bluhm Cardiovascular Institute, Northwestern Memorial Hospital, Chicago, Illinois
| | - Neil J Stone
- Division of Cardiology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; Bluhm Cardiovascular Institute, Northwestern Memorial Hospital, Chicago, Illinois.
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9
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Axelsson KJ, Gransberg L, Lundahl G, Vahedi F, Bergfeldt L. Adaptation of ventricular repolarization time following abrupt changes in heart rate: comparisons and reproducibility of repeated atrial and ventricular pacing. Am J Physiol Heart Circ Physiol 2020; 320:H381-H392. [PMID: 33164576 DOI: 10.1152/ajpheart.00542.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adequate adaptation of ventricular repolarization (VR) duration to changes in heart rate (HR) is important for cardiac electromechanical function and electrical stability. We studied the QT and QTpeak adaptation in response to abrupt start and stop of atrial and ventricular pacing on two occasions with an interval of at least 1 mo in 25 study subjects with permanent pacemakers. Frank vectorcardiography was used for data collection. Atrial or ventricular pacing was performed for 8 min aiming at a cycle length (CL) of 500 ms. We measured the immediate response (IR), the time constant (τ) of the exponential phase, and T90 End, the time to reach 90% change of QT and QTpeak from baseline to steady state during and after pacing. During atrial pacing, the CL decreased on average 45% from mean (SD) 944 (120) to 518 (46) ms and QT decreased on average 18% from 388 (20) to 318 (17) ms. For QT, T90 End was 103 (24) s and 126 (15) s after start versus stop of atrial pacing; a difference of 24 (27) s (P = 0.006). The response pattern was similar for τ but IR did not differ significantly between pacing start and stop. The response pattern was similar for QTpeak and also for QT and QTpeak following ventricular pacing start and stop. The coefficients of variation for repeated measures were 7%-21% for T90 End and τ. In conclusion, the adaptation of VR duration was significantly more rapid following increasing than decreasing HR and intraindividually a relatively reproducible process.NEW & NOTEWORTHY We studied the duration of ventricular repolarization (VR) adaptation and its hysteresis, following increasing and decreasing heart rate by abrupt start and stop of 8-min atrial or ventricular pacing in study subjects with permanent pacemakers and repeated the protocol with ≥1 mo interval, a novel approach. VR adaptation was significantly longer following decreasing than increasing heart rate corroborating previous observations. Furthermore, VR adaptation was intraindividually a reproducible and, hence, robust phenomenon, a novel finding.
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Affiliation(s)
- Karl-Jonas Axelsson
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Cardiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg Sweden
| | - Lennart Gransberg
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Gunilla Lundahl
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Farzad Vahedi
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Cardiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg Sweden
| | - Lennart Bergfeldt
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Cardiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg Sweden
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10
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Kichloo A, Haji AQ, Kanjwal K. Cardiac memory presenting as ST elevations following premature ventricular complex ablation. HeartRhythm Case Rep 2020; 7:52-55. [PMID: 33505856 PMCID: PMC7813796 DOI: 10.1016/j.hrcr.2020.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Asim Kichloo
- Department of Internal Medicine, Samaritan Medical Center, Watertown, New York
- Department of Internal Medicine, Central Michigan University, Saginaw, Michigan
| | - Abdul Qadir Haji
- Department of Cardiology, Martinsburg VA Medical Center, Martinsburg, West Virginia
| | - Khalil Kanjwal
- Department of Electrophysiology, McLaren Greater Lansing Hospital, Lansing, Michigan
- Address reprint requests and correspondence: Dr Khalil Kanjwal, Clinical Associate Professor of Medicine, Michigan State University, McLaren Greater Lansing Hospital, Lansing, MI 48901.
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11
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Axelsson KJ, Brännlund A, Gransberg L, Lundahl G, Vahedi F, Bergfeldt L. Adaptation of ventricular repolarization duration and dispersion during changes in heart rate induced by atrial stimulation. Ann Noninvasive Electrocardiol 2019; 25:e12713. [PMID: 31707762 PMCID: PMC7358894 DOI: 10.1111/anec.12713] [Citation(s) in RCA: 5] [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] [Received: 07/11/2019] [Revised: 09/03/2019] [Accepted: 09/11/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The duration of ventricular repolarization (VR) and its spatial and temporal heterogeneity are central elements in arrhythmogenesis. We studied the adaptation of VR duration and dispersion and their relationship in healthy human subjects during atrial pacing. METHODS Patients 20-50 years of age who were scheduled for ablation of supraventricular tachycardia without preexcitation but otherwise healthy were eligible. Vectorcardiography recordings with Frank leads were used for data collection. Incremental atrial pacing from a coronary sinus electrode was performed by decrements of 10ms/cycle from just above sinus rate, and then kept at a fixed heart rate (HR) just below the Wenckebach rate for ≥5min and then stopped. VR duration was measured as QT and VR dispersion as T area, T amplitude and ventricular gradient. The primary measure (T90 End) was the time to reach 90% change from baseline to the steady state value during and after pacing. RESULTS A complete study protocol was accomplished in 9 individuals (6 women). VR duration displayed a monophasic adaptation during HR acceleration lasting on average 20s. The median (Q1-Q3) T90 End for QT was 85s (51-104), a delay by a factor >4. All dispersion measures displayed a tri-phasic response pattern during HR acceleration and T90 End was 3-5 times shorter than for VR duration. CONCLUSIONS Even during close to "physiological" conditions, complex and differing response patterns in VR duration and dispersion measures followed changes in HR. Extended knowledge about these responses in disease conditions might assist in risk evaluation and finding therapeutic alternatives.
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Affiliation(s)
- Karl-Jonas Axelsson
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Cardiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Adam Brännlund
- Department of Anesthesiology and Intensive Care Medicine, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Lennart Gransberg
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Gunilla Lundahl
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Farzad Vahedi
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Cardiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Lennart Bergfeldt
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Cardiology, Region Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden
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12
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Siontis KC, Wen S, Asirvatham SJ. Cardiac memory for the clinical electrophysiologist. J Cardiovasc Electrophysiol 2019; 30:2140-2143. [DOI: 10.1111/jce.14134] [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: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 11/30/2022]
Affiliation(s)
| | - Songnan Wen
- Department of Cardiovascular DiseasesMayo ClinicRochester Minnesota
| | - Samuel J. Asirvatham
- Department of Cardiovascular DiseasesMayo ClinicRochester Minnesota
- Department of Pediatrics and Adolescent MedicineMayo ClinicRochester Minnesota
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13
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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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14
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Sakamoto Y, Inden Y, Okamoto H, Mamiya K, Tomomatsu T, Fujii A, Yanagisawa S, Shibata R, Hirai M, Murohara T. T-wave changes of cardiac memory caused by frequent premature ventricular contractions originating from the right ventricular outflow tract. J Cardiovasc Electrophysiol 2019; 30:1549-1556. [PMID: 31157487 DOI: 10.1111/jce.14008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/16/2019] [Accepted: 04/30/2019] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Cardiac memory is recognized as altered T-waves when the sinus rhythm resumes after an abnormal myocardial activation period that recovers slowly over several weeks. The T-wave changes after ablation of frequent premature ventricular contractions (PVCs) as cardiac memory was not known. OBJECTIVE This study identified whether cardiac memory exists after successful ablation of PVCs from the right ventricular outflow tract (RVOT). METHODS We investigated 45 patients who underwent successful ablation of PVCs from RVOT and 10 patients who underwent unsuccessful ablation. We analyzed the amplitude of the T-wave, QT intervals, and QRST time-integral values of a 12-lead electrocardiogram before ablation and 1 day, 3 days, and 1 month after ablation. RESULTS In the successful ablation group, the amplitude of the T-wave and QRST time-integral values of lead II, III, aVR, aVL, and aVF significantly changed after ablation and gradually normalized within 1 month. In addition, if the number of pre-ablation PVCs was small, then the corresponding impact was also small. However, the greater the number of pre-ablation PVCs, the more prominent the changes. Significant changes were not observed in the unsuccessful ablation group. CONCLUSION When ablation of PVCs from RVOT was successful, primary T-wave changes because of cardiac memory and the gradual normalization of the amplitude of the T-wave were observed. No significant T-wave changes were detected after unsuccessful ablation.
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Affiliation(s)
- Yusuke Sakamoto
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuya Inden
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroya Okamoto
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Keita Mamiya
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toshiro Tomomatsu
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Aya Fujii
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Satoshi Yanagisawa
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Rei Shibata
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Makoto Hirai
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Toyoaki Murohara
- Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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15
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More frequent postextrasystolic potentiation in patients with premature ventricular contraction-related cardiomyopathy: The missing link between premature ventricular contractions and cardiomyopathy? Heart Rhythm 2018; 16:861-862. [PMID: 30576882 DOI: 10.1016/j.hrthm.2018.12.016] [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: 12/10/2018] [Indexed: 11/23/2022]
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16
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Peck D, Al-Kaisey A. Cardiac memory: an under-recognised cause of deep T wave inversion in a patient presenting with chest pain. BMJ Case Rep 2018; 2018:bcr-2018-225476. [PMID: 30061136 DOI: 10.1136/bcr-2018-225476] [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] [Indexed: 01/04/2023] Open
Abstract
T wave inversion (TWI) has many differential diagnoses with acute myocardial ischaemia being the highest on the list of potential causes. Cardiac T wave memory is a benign, under-recognised and clinically important phenomenon seen after periods of altered ventricular conduction. After normal ventricular conduction is restored, the T wave 'remembers' and mirrors the direction of the wide QRS complex. Therefore, negative T waves are seen in leads that had negative wide QRS complexes. We describe the case of a 60-year-old truck driver with chest pain, deep TWI and traditional cardiovascular risk factors. After ruling out significant myocardial ischaemia, it was crucial to determine the cause of his T wave changes to provide reassurance and provide commercial license medical clearance. While it is currently a diagnosis of exclusion, it remains an important clinical entity for clinicians to recognise to provide an explanation for certain T wave changes to avoid future unnecessary cardiac testing.
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Affiliation(s)
- Daniel Peck
- Department of Cardiology, Austin Heath, Heidelberg, Australia
| | - Ahmed Al-Kaisey
- Department of Cardiology, Austin Heath, Heidelberg, Australia
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17
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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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18
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Jiang M, Wang Y, Tseng GN. Adult Ventricular Myocytes Segregate KCNQ1 and KCNE1 to Keep the IKs Amplitude in Check Until When Larger IKs Is Needed. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.005084. [PMID: 28611207 DOI: 10.1161/circep.117.005084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/15/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND KCNQ1 and KCNE1 assemble to form the slow delayed rectifier (IKs) channel critical for shortening ventricular action potentials during high β-adrenergic tone. However, too much IKs under basal conditions poses an arrhythmogenic risk. Our objective is to understand how adult ventricular myocytes regulate the IKs amplitudes under basal conditions and in response to stress. METHODS AND RESULTS We express fluorescently tagged KCNQ1 and KCNE1 in adult ventricular myocytes and follow their biogenesis and trafficking paths. We also study the distribution patterns of native KCNQ1 and KCNE1, and their relationship to IKs amplitudes, in chronically stressed ventricular myocytes, and use COS-7 cell expression to probe the underlying mechanism. We show that KCNQ1 and KCNE1 are both translated in the perinuclear region but traffic by different routes, independent of each other, to their separate subcellular locations. KCNQ1 mainly resides in the jSR (junctional sarcoplasmic reticulum), whereas KCNE1 resides on the cell surface. Under basal conditions, only a small portion of KCNQ1 reaches the cell surface to support the IKs function. However, in response to chronic stress, KCNQ1 traffics from jSR to the cell surface to boost the IKs amplitude in a process depending on Ca binding to CaM (calmodulin). CONCLUSIONS In adult ventricular myocytes, KCNE1 maintains a stable presence on the cell surface, whereas KCNQ1 is dynamic in its localization. KCNQ1 is largely in an intracellular reservoir under basal conditions but can traffic to the cell surface and boost the IKs amplitude in response to stress.
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Affiliation(s)
- Min Jiang
- From the Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond (M.J., Y.W., G.-N.T.); and Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (M.J.)
| | - Yuhong Wang
- From the Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond (M.J., Y.W., G.-N.T.); and Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (M.J.)
| | - Gea-Ny Tseng
- From the Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond (M.J., Y.W., G.-N.T.); and Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (M.J.).
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19
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Kobrinsky E. Heterogeneity of Calcium Channel/cAMP-Dependent Transcriptional Activation. Curr Mol Pharmacol 2016; 8:54-60. [PMID: 25966705 DOI: 10.2174/1874467208666150507093601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/06/2015] [Accepted: 04/20/2015] [Indexed: 12/22/2022]
Abstract
The major function of the voltage-gated calcium channels is to provide the Ca(2+) flux into the cell. L-type voltage-gated calcium channels (Cav1) serve as voltage sensors that couple membrane depolarization to many intracellular processes. Electrical activity in excitable cells affects gene expression through signaling pathways involved in the excitation-transcription (E-T) coupling. E-T coupling starts with activation of the Cav1 channel and results in initiation of the cAMP-response element binding protein (CREB)-dependent transcription. In this review we discuss the new quantitative approaches to measuring E-T signaling events. We describe the use of wavelet transform to detect heterogeneity of transcriptional activation in nuclei. Furthermore, we discuss the properties of discovered microdomains of nuclear signaling associated with the E-T coupling and the basis of the frequency-dependent transcriptional regulation.
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Affiliation(s)
- Evgeny Kobrinsky
- National Institute on Aging, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, US.
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20
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Srinivasan NT, Orini M, Simon RB, Providência R, Khan FZ, Segal OR, Babu GG, Bradley R, Rowland E, Ahsan S, Chow AW, Lowe MD, Taggart P, Lambiase PD. Ventricular stimulus site influences dynamic dispersion of repolarization in the intact human heart. Am J Physiol Heart Circ Physiol 2016; 311:H545-54. [PMID: 27371682 PMCID: PMC5142177 DOI: 10.1152/ajpheart.00159.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/29/2016] [Indexed: 12/18/2022]
Abstract
Spatial variation of restitution in relation to varying stimulus site is poorly defined in the intact human heart. Repolarization gradients were shown to be dependent on site of activation with epicardial stimulation promoting significant transmural gradients. Steep restitution slopes were predominant in the normal ventricle. The spatial variation in restitution properties in relation to varying stimulus site is poorly defined. This study aimed to investigate the effect of varying stimulus site on apicobasal and transmural activation time (AT), action potential duration (APD) and repolarization time (RT) during restitution studies in the intact human heart. Ten patients with structurally normal hearts, undergoing clinical electrophysiology studies, were enrolled. Decapolar catheters were placed apex to base in the endocardial right ventricle (RVendo) and left ventricle (LVendo), and an LV branch of the coronary sinus (LVepi) for transmural recording. S1–S2 restitution protocols were performed pacing RVendo apex, LVendo base, and LVepi base. Overall, 725 restitution curves were analyzed, 74% of slopes had a maximum slope of activation recovery interval (ARI) restitution (Smax) > 1 (P < 0.001); mean Smax = 1.76. APD was shorter in the LVepi compared with LVendo, regardless of pacing site (30-ms difference during RVendo pacing, 25-ms during LVendo, and 48-ms during LVepi; 50th quantile, P < 0.01). Basal LVepi pacing resulted in a significant transmural gradient of RT (77 ms, 50th quantile: P < 0.01), due to loss of negative transmural AT-APD coupling (mean slope 0.63 ± 0.3). No significant transmural gradient in RT was demonstrated during endocardial RV or LV pacing, with preserved negative transmural AT-APD coupling (mean slope −1.36 ± 1.9 and −0.71 ± 0.4, respectively). Steep ARI restitution slopes predominate in the normal ventricle and dynamic ARI; RT gradients exist that are modulated by the site of activation. Epicardial stimulation to initiate ventricular activation promotes significant transmural gradients of repolarization that could be proarrhythmic.
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Affiliation(s)
- Neil T Srinivasan
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Michele Orini
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Ron B Simon
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Rui Providência
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Fakhar Z Khan
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Oliver R Segal
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Girish G Babu
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Richard Bradley
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Edward Rowland
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Syed Ahsan
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Anthony W Chow
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Martin D Lowe
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Pier D Lambiase
- Department of Cardiac Electrophysiology, The Barts Heart Center, St Bartholomew's Hospital, London, United Kingdom; and Institute of Cardiovascular Science, University College London, London, United Kingdom
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21
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Abstract
The genesis of cardiac resynchronisation therapy (CRT) consists of 'bedside' research and 'bench' studies that are performed in series with each other. In this field, the bench studies are crucial for understanding the pathophysiology of dyssynchrony and resynchronisation. In a way, CRT started with the insight that abnormal ventricular conduction, as caused by right ventricular pacing, has adverse effects. Out of this research came the ground-breaking insight that 'simple' disturbances in impulse conduction, which were initially considered innocent, proved to result in a host of molecular and cellular derangements that lead to a vicious circle of remodelling processes that facilitate the development of heart failure. As a consequence, CRT does not only correct conduction abnormalities, but also improves myocardial properties at many levels. Interestingly, corrections by CRT do not exactly reverse the derangements, induced by dyssynchrony, but also activate novel pathways, a property that may open new avenues for the treatment of heart failure.
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Affiliation(s)
- R F Wiegerinck
- Department of Physiology, Cardiovascular Research Institute Maastricht, PO Box 616, 6200 MD, Maastricht, The Netherlands
| | - R Schreurs
- Department of Physiology, Cardiovascular Research Institute Maastricht, PO Box 616, 6200 MD, Maastricht, The Netherlands
| | - F W Prinzen
- Department of Physiology, Cardiovascular Research Institute Maastricht, PO Box 616, 6200 MD, Maastricht, The Netherlands.
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22
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Cardiac memory: The slippery slope twixt normalcy and pathology. Trends Cardiovasc Med 2015; 25:687-96. [DOI: 10.1016/j.tcm.2015.02.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 12/19/2022]
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23
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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: 31] [Impact Index Per Article: 3.4] [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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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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25
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Rosso R, Adler A, Strasberg B, Guevara-Valdivia ME, Somani R, Baranchuk A, Halkin A, Márquez MF, Scheinman M, Steinvil A, Belhassen B, Kazatsker M, Katz A, Viskin S. Long QT Syndrome Complicating Atrioventricular Block. Circ Arrhythm Electrophysiol 2014; 7:1129-35. [DOI: 10.1161/circep.114.002085] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
The magnitude of QT prolongation in response to bradycardia, rather than the bradycardia per se, determines the risk for torsade de pointes during atrioventricular block (AVB). However, we do not know why some patients develop more QT prolongation than others, despite similar bradycardia. We hypothesized that in patients who develop significant QRS vector changes during AVB, the effects of cardiac memory lead to excessive QT prolongation.
Methods and Results—
We studied 91 patients who presented with AVB and who also had an ECG predating the bradyarrhythmia for comparison. We correlated changes in QRS morphology and axis taking place during AVB with the bradycardia-induced QT prolongation. Patients with and without QRS morphology changes at the time of AVB were of similar age and sex. Moreover, despite similar R-R interval during AVB, cases with a QRS morphology change had significantly longer QT (648±84 versus 561±84;
P
<0.001) than those without. Patients who developed a change in QRS morphology at the time of AVB had a 7-fold higher risk of developing long QT. This risk nearly doubled when the change in QRS morphology was accompanied by a change in QRS axis.
Conclusions—
Cardiac memory resulting from a change in QRS morphology during AVB is independently associated with QT prolongation and may be arrhythmogenic during AVB.
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Affiliation(s)
- Raphael Rosso
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Arnon Adler
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Boris Strasberg
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Milton E. Guevara-Valdivia
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Riyaz Somani
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Adrian Baranchuk
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Amir Halkin
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Manlio F. Márquez
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Melvin Scheinman
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Arie Steinvil
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Bernard Belhassen
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Mark Kazatsker
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Amos Katz
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
| | - Sami Viskin
- From the Tel Aviv Sourasky Medical Center (R.R., A.A., A.H., A.S., B.B., S.V.) and Rabin Medical Center, Petah-Tikva (B.S.), Sackler School of Medicine, Tel Aviv University, Israel; UMAE Hospital de Especialidades Dr. Antonio Fraga Mouret, CMN La Raza IMSS, Mexico (M.E.G.-V.); Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico (M.F.M.); Kingston General Hospital, Queen’s University, Kingston, ON, Canada (R.S., A.B.); University of California San Francisco (M.S.); Hillel Yaffe
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Chiale PA, Etcheverry D, Pastori JD, Fernandez PA, Garro HA, González MD, Elizari MV. The multiple electrocardiographic manifestations of ventricular repolarization memory. Curr Cardiol Rev 2014; 10:190-201. [PMID: 24827802 PMCID: PMC4040871 DOI: 10.2174/1573403x10666140514102021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 05/28/2013] [Accepted: 01/28/2014] [Indexed: 11/22/2022] Open
Abstract
T wave “memory” is a peculiar variety of cardiac remodeling caused by a transient change in the course of ventricular depolarization (due to ventricular pacing, rate-dependent intraventricular block, ventricular preexcitation or tachyarrhythmias with wide QRS complexes). It is usually manifested by inverted T waves that appears when normal ventricular activation is restored. This phenomenon is cumulative and occurs earlier if the ventricular myocardium has previously been exposed to the same conditioning stimuli. In this article the different conditions giving rise to “classical” T wave memory development are reviewed and also “another” type of T wave memory is described. It is also shown that cardiac memory may induce not only negative (pseudo-primary) T waves but also a reversal of primary and pseudo-primary T waves leading to “normalization” of ventricular repolarization. The knowledge of these dissimilar consequences of T wave memory is essential to assess the characteristics of ventricular repolarization.
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Affiliation(s)
| | | | | | | | | | | | - Marcelo V Elizari
- Centro de Arritmias Cardíacas de la Ciudad Autónoma de Buenos Aires. Cardiology Division. Hospital J.M. Ramos Mejía. Buenos Aires. Argentina.
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27
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Chiale PA, Etcheverry D, Pastori JD, Garro HA, Fernández PA, González MD, Elizari MV. Clinical Evaluation of Losartan and Diltiazem on the Development of T-Wave Memory by Right Apical Ventricular Pacing. J Am Coll Cardiol 2014; 63:1929-31. [DOI: 10.1016/j.jacc.2014.02.524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/30/2014] [Accepted: 02/04/2014] [Indexed: 11/27/2022]
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Laughner JI, Marrus SB, Zellmer ER, Weinheimer CJ, MacEwan MR, Cui SX, Nerbonne JM, Efimov IR. A fully implantable pacemaker for the mouse: from battery to wireless power. PLoS One 2013; 8:e76291. [PMID: 24194832 PMCID: PMC3806780 DOI: 10.1371/journal.pone.0076291] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/22/2013] [Indexed: 11/19/2022] Open
Abstract
Animal models have become a popular platform for the investigation of the molecular and systemic mechanisms of pathological cardiovascular physiology. Chronic pacing studies with implantable pacemakers in large animals have led to useful models of heart failure and atrial fibrillation. Unfortunately, molecular and genetic studies in these large animal models are often prohibitively expensive or not available. Conversely, the mouse is an excellent species for studying molecular mechanisms of cardiovascular disease through genetic engineering. However, the large size of available pacemakers does not lend itself to chronic pacing in mice. Here, we present the design for a novel, fully implantable wireless-powered pacemaker for mice capable of long-term (>30 days) pacing. This design is compared to a traditional battery-powered pacemaker to demonstrate critical advantages achieved through wireless inductive power transfer and control. Battery-powered and wireless-powered pacemakers were fabricated from standard electronic components in our laboratory. Mice (n = 24) were implanted with endocardial, battery-powered devices (n = 14) and epicardial, wireless-powered devices (n = 10). Wireless-powered devices were associated with reduced implant mortality and more reliable device function compared to battery-powered devices. Eight of 14 (57.1%) mice implanted with battery-powered pacemakers died following device implantation compared to 1 of 10 (10%) mice implanted with wireless-powered pacemakers. Moreover, device function was achieved for 30 days with the wireless-powered device compared to 6 days with the battery-powered device. The wireless-powered pacemaker system presented herein will allow electrophysiology studies in numerous genetically engineered mouse models as well as rapid pacing-induced heart failure and atrial arrhythmia in mice.
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Affiliation(s)
- Jacob I. Laughner
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Scott B. Marrus
- Department of Internal Medicine, Division of Cardiovascular Sciences, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Erik R. Zellmer
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Carla J. Weinheimer
- Department of Internal Medicine, Division of Cardiovascular Sciences, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Matthew R. MacEwan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Sophia X. Cui
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Jeanne M. Nerbonne
- Department of Developmental Biology, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Igor R. Efimov
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
- * E-mail:
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29
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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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30
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Cardiomyopathy-inducing premature ventricular contractions: Not all animals are equal? Heart Rhythm 2012; 9:1473-4. [DOI: 10.1016/j.hrthm.2012.06.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Indexed: 11/23/2022]
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Tseng GN. Short-term memory in the heart: a road map for channel trafficking required. Heart Rhythm 2012; 9:1873-4. [PMID: 22885920 DOI: 10.1016/j.hrthm.2012.08.014] [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: 08/02/2012] [Indexed: 10/28/2022]
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32
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Özgen N, Lu Z, Boink GJJ, Lau DH, Shlapakova IN, Bobkov Y, Danilo P, Cohen IS, Rosen MR. Microtubules and angiotensin II receptors contribute to modulation of repolarization induced by ventricular pacing. Heart Rhythm 2012; 9:1865-72. [PMID: 22820054 DOI: 10.1016/j.hrthm.2012.07.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Indexed: 01/09/2023]
Abstract
BACKGROUND Left ventricular pacing (LVP) in canine heart alters ventricular activation, leading to reduced transient outward potassium current (I(to)), loss of the epicardial action potential notch, and T-wave vector displacement. These repolarization changes, referred to as cardiac memory, are initiated by locally increased angiotensin II (AngII) levels. In HEK293 cells in which Kv4.3 and KChIP2, the channel subunits contributing to I(to), are overexpressed with the AngII receptor 1 (AT1R), AngII induces a decrease in I(to) as the result of internalization of a Kv4.3/KChIP2/AT1R macromolecular complex. OBJECTIVE To test the hypothesis that in canine heart in situ, 2h LVP-induced decreases in membrane KChIP2, AT1R, and I(to) are prevented by blocking subunit trafficking. METHODS We used standard electrophysiological, biophysical, and biochemical methods to study 4 groups of dogs: (1) Sham, (2) 2h LVP, (3) LVP + colchicine (microtubule-disrupting agent), and (4) LVP + losartan (AT1R blocker). RESULTS The T-wave vector displacement was significantly greater in LVP than in Sham and was inhibited by colchicine or losartan. Epicardial biopsies showed significant decreases in KChIP2 and AT1R proteins in the membrane fraction after LVP but not after sham treatment, and these decreases were prevented by colchicine or losartan. Colchicine but not losartan significantly reduced microtubular polymerization. In isolated ventricular myocytes, AngII-induced I(to) reduction and loss of action potential notch were blocked by colchicine. CONCLUSIONS LVP-induced reduction of KChIP2 in plasma light membranes depends on an AngII-mediated pathway and intact microtubular status. Loss of I(to) and the action potential notch appear to derive from AngII-initiated trafficking of channel subunits.
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Affiliation(s)
- Nazira Özgen
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
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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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Sorgente A, Josephson ME. Don't forget the memory: Contribution of the T wave vector in localizing the site of origin of a monomorphic idiopathic ventricular tachycardia. J Cardiol Cases 2011; 5:e28-e31. [PMID: 30532896 DOI: 10.1016/j.jccase.2011.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/18/2011] [Accepted: 09/02/2011] [Indexed: 12/01/2022] Open
Abstract
We report a case of cardiac memory following recurrent episodes of monomorphic idiopathic ventricular tachycardia and explain how it could be helpful in localizing the site of origin of the arrhythmia.
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Affiliation(s)
- Antonio Sorgente
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Beth Israel Deaconess Medical Center, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA.,Department of Cardiology, University of L'Aquila, L'Aquila, Italy
| | - Mark E Josephson
- Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Beth Israel Deaconess Medical Center, Boston, MA, USA
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Cutler MJ, Jeyaraj D, Rosenbaum DS. Cardiac electrical remodeling in health and disease. Trends Pharmacol Sci 2011; 32:174-80. [PMID: 21316769 DOI: 10.1016/j.tips.2010.12.001] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 11/25/2010] [Accepted: 12/01/2010] [Indexed: 01/12/2023]
Abstract
Electrical remodeling of the heart takes place in response to both functional (altered electrical activation) and structural (including heart failure and myocardial infarction) stressors. These electrophysiological changes produce a substrate that is prone to malignant ventricular arrhythmias. Understanding the cellular and molecular mechanisms of electrical remodeling is important in elucidating potential therapeutic targets designed to alter maladaptive electrical remodeling. For example, altered patterns of electrical activation lead primarily to electrical remodeling, without significant structural remodeling. By contrast, secondary remodeling arises in response to a structural insult. In this article we review cardiac electrical remodeling (predominantly in the ventricle) with an emphasis on the mechanisms causing these adaptations. These mechanisms suggest novel therapeutic targets for the management or prevention of the most devastating manifestation of heart disease, sudden cardiac death (SCD).
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Affiliation(s)
- Michael J Cutler
- The Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
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Van de Heyning CM, Moerenhout CM, Vrints CJ. Case report: Chest pain, intermittent left bundle branch block and negative T waves. Int J Cardiol 2011; 147:302-4. [PMID: 21215481 DOI: 10.1016/j.ijcard.2010.12.059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
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Yamazaki KG, Villarreal FJ. Ventricular pacing-induced loss of contractile function and development of epicardial inflammation. Am J Physiol Heart Circ Physiol 2011; 300:H1282-90. [PMID: 21297025 DOI: 10.1152/ajpheart.01079.2010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Perturbations in the normal sequence of ventricular activation can create regions of early and late activation, leading to dysynchronous contraction and areas of dyskinesis. Dyskinesis occurs across the left ventricular (LV) wall, and its presence may have important consequences on cardiac structure and function in normal and failing hearts. Acutely, dyskinesis can trigger inflammation and, in the long term (6 wk and above), leads to LV remodeling. The mechanisms that trigger these changes are unknown. To gain further insight, we used a canine model to evaluate transumural changes in myocardial function and inflammation induced by epicardial LV pacing. The results indicate that 4 h of LV suprathreshold pacing resulted in a 30% local loss of endocardial thickening. Assessment of neutrophil infiltration showed a significant approximately fivefold increase in myeloperoxidase activity in the epicardium versus the midwall/endocardium. Matrix metalloproteinase-9 activity increased ∼2 fold in the epicardium and ROS generation increased ∼2.5-fold compared with the midwall/endocardium. To determine the effects that electrical current alone has on these end points, a group of animals was subjected to subthreshold pacing. Significant increases were observed only in epicardial myeloperoxidase levels. Thus, the results indicate that transmural dyskinesis induced by suprathreshold epicardial LV activation triggers a localized epicardial inflammatory response, whereas subthreshold stimulation appears to solely induce the trapping of leucocytes. Suprathreshold pacing also induces a loss of endocardial function. These results may have important implications as to the nature of the mechanisms that trigger the inflammatory response and possibly long-term remodeling in the setting of dysynchrony.
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Affiliation(s)
- Katrina Go Yamazaki
- Departments of 1Pharmacology, University of California-San Diego, La Jolla, 92093-0613, USA
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Kobrinsky E, Duong SQ, Sheydina A, Soldatov NM. Microdomain organization and frequency-dependence of CREB-dependent transcriptional signaling in heart cells. FASEB J 2011; 25:1544-55. [PMID: 21248242 DOI: 10.1096/fj.10-176198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Voltage-gated Ca(v)1.2 calcium channels couple membrane depolarization to cAMP response-element-binding protein (CREB)-dependent transcriptional activation. To investigate the spatial and temporal organization of CREB-dependent transcriptional nuclear microdomains, we combined perforated patch-clamp technique and FRET microscopy for monitoring CREB and CREB-binding protein interaction in the nuclei of live cells. The experimental approach to the quantitative assessment of CREB-dependent transcriptional signaling evoked by cAMP- and Ca(v)1.2-dependent mechanisms was devised in COS1 cells expressing recombinant Ca(v)1.2 calcium channels. Using continuous 2-dimensional wavelet transform and time series analyses, we found that nuclear CREB-dependent transcriptional signaling is organized differentially in spatially and temporally separated microdomains of 4 distinct types. In rat neonatal cardiomyocytes, CREB-dependent transcription is mediated by the cAMP-initiated CaMKII-sensitive and Ca(v)1.2-initiated CaMKII-insensitive mechanisms. The latter microdomains show a tendency to exhibit periodic behavior correlated with spontaneous contraction of myocytes suggestive of frequency-dependent CREB-dependent transcriptional regulation in the heart.
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Affiliation(s)
- Evgeny Kobrinsky
- National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
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Ozgen N, Lau DH, Shlapakova IN, Sherman W, Feinmark SJ, Danilo P, Rosen MR. Determinants of CREB degradation and KChIP2 gene transcription in cardiac memory. Heart Rhythm 2010; 7:964-70. [PMID: 20346417 DOI: 10.1016/j.hrthm.2010.03.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 03/19/2010] [Indexed: 01/12/2023]
Abstract
BACKGROUND Left ventricular pacing (LVP) to induce cardiac memory (CM) in dogs results in a decreased transient outward K current (I(to)) and reduced mRNA and protein of the I(to) channel accessory subunit, KChIP2. The KChIP2 decrease is attributed to a decrease in its transcription factor, cyclic adenosine monophosphate response element binding protein (CREB). OBJECTIVE This study sought to determine the mechanisms responsible for the CREB decrease that is initiated by LVP. METHODS CM was quantified as T-wave vector displacement in 18 LVP dogs. In 5 dogs, angiotensin II receptor blocker, saralasin, was infused before and during pacing. In 3 dogs, proteasomal inhibitor, lactacystin, was injected into the left anterior descending artery before LVP. Epicardial biopsy samples were taken before and after LVP. Neonatal rat cardiomyocytes (NRCM) were incubated with H(2)O(2) (50 micromol/l) for 1 hour with or without lactacystin. RESULTS LVP significantly displaced the T-wave vector and was associated with increased lipid peroxidation and increased tissue angiotensin II levels. Saralasin prevented T-vector displacement and lipid peroxidation. CREB was significantly decreased after 2 hours of LVP and was comparably decreased in H(2)O(2)-treated NRCM. Lactacystin inhibited the CREB decrease in LVP dogs and H(2)O(2)-treated NRCM. LVP and H(2)O(2) both induced CREB ubiquitination, and the H(2)O(2)-induced CREB decrease was prevented by knocking down ubiquitin. CONCLUSION LVP initiates myocardial angiotensin II production and reactive oxygen species synthesis, leading to CREB ubiquitination and its proteasomal degradation. This sequence of events would explain the pacing-induced reduction in KChIP2, and contribute to altered repolarization and the T-wave changes of cardiac memory.
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Affiliation(s)
- Nazira Ozgen
- Department of Pharmacology, Columbia University, New York, New York 10032, USA.
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Chiale PA, Pastori JD, Garro HA, Faivelis L, Ianovsky O, Sánchez RA, Alvarez CB, González MD, Elizari MV. Reversal of primary and pseudo-primary T wave abnormalities by ventricular pacing. A novel manifestation of cardiac memory. J Interv Card Electrophysiol 2010; 28:23-33. [PMID: 20333458 DOI: 10.1007/s10840-010-9473-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 01/27/2010] [Indexed: 10/19/2022]
Abstract
AIMS "Cardiac memory" refers to abnormal T waves (TW) appearing after transient periods of altered ventricular depolarization. The aim of the study was to test the hypothesis that in the presence of abnormal TW, short periods of tailored ventricular pacing (VP) can be followed by normalization of ventricular repolarization. METHODS Ten patients with normal TW (control group) and 18 patients with abnormal TW (study group) underwent 15 min of VP at a cycle length of 500 ms. In the control group, VP was performed from the right ventricular apex, and in the study group from right or left ventricular sites that resulted in paced QRS complexes of opposite polarity to that of the abnormal TW. Before and after VP, atrial pacing was maintained at a stable cycle length. Simultaneous 12-lead electrocardiography (ECG) was recorded before, during, and following VP to assess changes in TW polarity, amplitude, electrical axis, QTc interval, and QTc interval dispersion. RESULTS As expected, VP was followed by memory-induced changes in TW in eight of ten patients in the control group. Mean T wave axis shifted from +60 degrees + or - 21.2 degrees to +23.5 degrees + or - 50.7 degrees (p = 0.01) in the frontal plane. In the study group, complete or partial normalization of TW occurred in 17 of 18 patients. Mean T wave axis shifted from -23.7 degrees + or - 22.9 degrees to +19.7 degrees + or - 34.7 degrees (p < 0.0002) in the frontal plane when paced from right ventricular outflow tract. The QTc interval shortened after VP both in the control group (424 + or - 25 vs. 399 + or - 27 ms; p = 0.007) and in the study group (446 + or - 26 vs. 421 + or - 22 ms; p < 0.0002). No significant changes were found in QTc interval dispersion. CONCLUSIONS Transient changes in the sequence of ventricular activation may either induce or normalize abnormal TW. The background of preceding ventricular depolarization needs to be taken into account before determining the clinical significance of a given pattern of ventricular repolarization.
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Affiliation(s)
- Pablo A Chiale
- Centro de Arritmias Cardíacas de la Ciudad Autónoma de Buenos Aires, Division of Cardiology, Ramos Mejía Hospital, Buenos Aires, Argentina.
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Abstract
The following article is a personal reflection on my study of a subject which has long interested me. The subject is the T wave, and especially the T wave changes occurring as a marker of cardiac memory. My interest evolved over coffees that Mauricio Rosenbaum and I used to share at the Hotel Algonquin during his frequent trips from Buenos Aires to New York. There is something about the Algonquin, whose scarred wooden tabletops carry the imprints of Robert Benchley, Dorothy Parker, and the 1920's New York literati, and there was something about Mauricio-clinician-scientist, friend, and raconteur extraordinaire-that made his repeated challenges to me to "look at cardiac memory before you begin losing your own" irresistible. So began my personal voyage into trying to understand the T wave. My guideposts were the experiments of Wilson and Finch,(1) the astute observations of a host of investigators who followed, and Mauricio's iconoclastic insights. The story is far from over...I doubt I'll see the end of it in my lifetime. But if the beauty of discovery is in the voyage, then it has been - for me - a memorable trip.
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Affiliation(s)
- Michael R Rosen
- Department of Pharmacology, Center for Molecular Therapeutics, and Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
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