1
|
Lisin R, Balakin A, Mukhlynina E, Protsenko Y. Differences in Mechanical, Electrical and Calcium Transient Performance of the Isolated Right Atrial and Ventricular Myocardium of Guinea Pigs at Different Preloads (Lengths). Int J Mol Sci 2023; 24:15524. [PMID: 37958508 PMCID: PMC10650485 DOI: 10.3390/ijms242115524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/19/2023] [Accepted: 10/22/2023] [Indexed: 11/15/2023] Open
Abstract
There are only a few studies devoted to the comparative and simultaneous study of the mechanisms of the length-dependent regulation of atrial and ventricular contractility. Therefore, an isometric force-length protocol was applied to isolated guinea pig right atrial (RA) strips and ventricular (RV) trabeculae, with a simultaneous measurement of force (Frank-Starling mechanism) and Ca2+ transients (CaT) or transmembrane action potentials (AP). Over the entire length-range studied, the duration of isometric contraction, CaT and AP, were shorter in the RA myocardium than in the RV myocardium. The RA myocardium was stiffer than the RV myocardium. With the increasing length of the RA and RV myocardium, the amplitude and duration of isometric contraction and CaT increased, as well as the amplitude and area of the "CaT difference curves" (shown for the first time). However, the rates of the tension development and relaxation decreased. No contribution of AP duration to the heterometric regulation of isometric tension was found in either the RA or RV myocardium of the guinea pig. Changes in the degree of overlap of the contractile proteins of the guinea pig RA and RV myocardium mainly affect CaT kinetics but not AP duration.
Collapse
Affiliation(s)
| | - Alexandr Balakin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, 106 Pervomayskaya Str., Yekaterinburg 620049, Russia; (R.L.); (E.M.); (Y.P.)
| | | | | |
Collapse
|
2
|
Dickey GJ, Bian K, Islam SU, Khan HR, Rohr S, Mao H. Advancing Commotio cordis Safety Standards Using the Total Human Models for Safety (THUMS). Ann Biomed Eng 2023; 51:2070-2085. [PMID: 37227601 DOI: 10.1007/s10439-023-03235-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/02/2023] [Indexed: 05/26/2023]
Abstract
Commotio cordis is one of the leading causes of sudden cardiac death in youth baseball. Currently, there are chest protector regulations regarding the prevention of Commotio cordis in baseball and lacrosse; however, they are not fully optimized. For the advancement of Commotio cordis safety, it is vital to include various age groups and a variety of impact angles in the testing process. This study employed finite element models and simulated Commotio cordis-inducing baseball collisions for different velocities, impact angles, and age groups. Commotio cordis risk response was characterized in terms of left ventricular strain and pressure, chest band and rib deformation, and force from impact. Normalized rib and chest band deformation when correlated with left ventricular strain resulted in R2 = 0.72, and R2 = 0.76, while left ventricular pressure resulted in R2 = 0.77, R2 = 0.68 across all velocities and impact angles in the child models. By contrast, the resultant reaction force risk metric as used by the National Operating Committee on Standards for Athletic Equipment (NOCSAE) demonstrated a correlation of R2 = 0.20 in the child models to ventricular strain, while illustrating a correlation to pressure of R2 = 0.74. When exploring future revisions to Commotio cordis safety requirements, the inclusion of deformation-related risk metrics at the level of the left ventricle should be considered.
Collapse
Affiliation(s)
- Grant James Dickey
- School of Biomedical Engineering, University of Western Ontario, London, Canada
| | - Kewei Bian
- Department of Mechanical and Materials Engineering, Faculty of Engineering, University of Western Ontario, London, Canada
| | - Sakib Ul Islam
- Department of Mechanical and Materials Engineering, Faculty of Engineering, University of Western Ontario, London, Canada
| | - Habib R Khan
- Division of Cardiology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Stephan Rohr
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Haojie Mao
- School of Biomedical Engineering, University of Western Ontario, London, Canada.
- Department of Mechanical and Materials Engineering, Faculty of Engineering, University of Western Ontario, London, Canada.
| |
Collapse
|
3
|
Lazzerini PE, Accioli R, Acampa M, Zhang WH, Verrengia D, Cartocci A, Bacarelli MR, Xin X, Salvini V, Chen KS, Salvadori F, D’errico A, Bisogno S, Cevenini G, Marzotti T, Capecchi M, Laghi-Pasini F, Chen L, Capecchi PL, Boutjdir M. Interleukin-6 Elevation Is a Key Pathogenic Factor Underlying COVID-19-Associated Heart Rate-Corrected QT Interval Prolongation. Front Cardiovasc Med 2022; 9:893681. [PMID: 35665254 PMCID: PMC9161021 DOI: 10.3389/fcvm.2022.893681] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/13/2022] [Indexed: 12/13/2022] Open
Abstract
Background Heart rate-corrected QT interval (QTc) prolongation is prevalent in patients with severe coronavirus disease 2019 (COVID-19) and is associated with poor outcomes. Recent evidence suggests that the exaggerated host immune-inflammatory response characterizing the disease, specifically interleukin-6 (IL-6) increase, may have an important role, possibly via direct effects on cardiac electrophysiology. The aim of this study was to dissect the short-term discrete impact of IL-6 elevation on QTc in patients with severe COVID-19 infection and explore the underlying mechanisms. Methods We investigated the following mechanisms: (1) the QTc duration in patients with COVID-19 during the active phase and recovery, and its association with C-reactive protein (CRP) and IL-6 levels; (2) the acute impact of IL-6 administration on QTc in an in vivo guinea pig model; and (3) the electrophysiological effects of IL-6 on ventricular myocytes in vitro. Results In patients with active severe COVID-19 and elevated IL-6 levels, regardless of acute myocardial injury/strain and concomitant QT-prolonging risk factors, QTc was significantly prolonged and rapidly normalized in correlation with IL-6 decrease. The direct administration of IL-6 in an in vivo guinea pig model acutely prolongs QTc duration. Moreover, ventricular myocytes incubated in vitro with IL-6 show evident prolongation in the action potential, along with significant inhibition in the rapid delayed rectifier potassium current (IKr). Conclusion For the first time, we demonstrated that in severe COVID-19, systemic inflammatory activation can per se promote QTc prolongation via IL-6 elevation, leading to ventricular electric remodeling. Despite being transitory, such modifications may significantly contribute to arrhythmic events and associated poor outcomes in COVID-19. These findings provide a further rationale for current anti-inflammatory treatments for COVID-19, including IL-6-targeted therapies.
Collapse
Affiliation(s)
- Pietro Enea Lazzerini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
- *Correspondence: Pietro Enea Lazzerini,
| | - Riccardo Accioli
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | | | - Wen-Hui Zhang
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
- Department of Pharmacy, Maanshan People’s Hospital, Maanshan, China
| | - Decoroso Verrengia
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | | | - Maria Romana Bacarelli
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Xiaofeng Xin
- Department of Respiration, Affiliated Jinling Hospital School of Medicine, Nanjing University, Nanjing, China
| | - Viola Salvini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Ke-Su Chen
- School of Medicine, Nanjing University, Nanjing, China
| | - Fabio Salvadori
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Antonio D’errico
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Stefania Bisogno
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Gabriele Cevenini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Tommaso Marzotti
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Matteo Capecchi
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Franco Laghi-Pasini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Long Chen
- National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China
| | - Pier Leopoldo Capecchi
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Mohamed Boutjdir
- VA New York Harbor Healthcare System, New York, NY, United States
- SUNY Downstate Health Sciences University, New York, NY, United States
- NYU School of Medicine, New York, NY, United States
| |
Collapse
|
4
|
Taggart P, Pueyo E, van Duijvenboden S, Porter B, Bishop M, Sampedro-Puente DA, Orini M, Hanson B, Rinaldi CA, Gill JS, Lambiase P. Emerging evidence for a mechanistic link between low-frequency oscillation of ventricular repolarization measured from the electrocardiogram T-wave vector and arrhythmia. Europace 2021; 23:1350-1358. [PMID: 33880542 PMCID: PMC8427352 DOI: 10.1093/europace/euab009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Indexed: 11/17/2022] Open
Abstract
Strong recent clinical evidence links the presence of prominent oscillations of ventricular repolarization in the low-frequency range (0.04-0.15 Hz) to the incidence of ventricular arrhythmia and sudden death in post-MI patients and patients with ischaemic and non-ischaemic cardiomyopathy. It has been proposed that these oscillations reflect oscillations of ventricular action potential duration at the sympathetic nerve frequency. Here we review emerging evidence to support that contention and provide insight into possible underlying mechanisms for this association.
Collapse
Affiliation(s)
- Peter Taggart
- Department of Cardiovascular Sciences, University College London, London, UK
| | - Esther Pueyo
- BSICOS Group, 13A, 11S, Aragon, University of Zaragoza, Spain
- CIBER-BBN, Zaragoza, Spain
| | | | - Bradley Porter
- Department of Imaging Sciences and Biomedical Engineering, KCL, London, UK
| | - Martin Bishop
- Department of Imaging Sciences and Biomedical Engineering, KCL, London, UK
| | | | - M Orini
- Department of Cardiovascular Sciences, University College London, London, UK
| | - B Hanson
- UCL Mechanical Engineering, University College London, London, UK
| | | | | | - Pier Lambiase
- Department of Cardiovascular Sciences, University College London, London, UK
| |
Collapse
|
5
|
Thakore A, Nguyen J, Pollack S, Muehlbauer S, Chi B, Knight D, Mehrotra B, Stern J, Cao JJ, Lucore C, Levine J. Electrocardiographic manifestations of COVID-19: Effect on cardiac activation and repolarization. EClinicalMedicine 2021; 39:101057. [PMID: 34377967 PMCID: PMC8343356 DOI: 10.1016/j.eclinm.2021.101057] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Prolonged QT intervals are reported in patients with COVID-19. Additionally, virus particles in heart tissue and abnormal troponin levels have been reported. Consequently, we hypothesize that cardiac electrophysiologic abnormalities may be associated with COVID-19. METHODS This is a retrospective study between March 15th, 2020 and May 30th, 2020 of 828 patients with COVID-19 and baseline ECG. Corrected QT (QTc) and QRS intervals were measured from ECGs performed prior to intervention or administration of QT prolonging drugs. QTc and QRS intervals were evaluated as a function of disease severity (patients admitted versus discharged; inpatients admitted to medical unit vs ICU) and cardiac involvement (troponin elevation >0.03 ng/ml, elevated B-natriuretic peptide (BNP) or NT pro-BNP >500 pg/ml). Multivariable analysis was used to test for significance. Odds ratios for predictors of disease severity and mortality were generated. FINDINGS Baseline QTc of inpatients was prolonged compared to patients discharged (450.1±30.2 versus 423.4±21.7 msec, p<0.0001) and relative to a control group of patients with influenza (p=0.006). Inpatients with abnormal cardiac biomarkers had prolonged QTc and QRS compared to those with normal levels (troponin - QTc: 460.9±34.6 versus 445.3±26.6 msec, p<0.0001, QRS: 98.7±24.6 vs 90.5±16.9 msec, p<0.0001; BNP - QTc: 465.9±33.0 versus 446.0±26.2 msec, p<0.0001, QRS: 103.6±25.3 versus 90.6±17.6 msec, p<0.0001). Findings were confirmed with multivariable analysis (all p<0.05). QTc prolongation independently predicted mortality (8.3% increase in mortality for every 10 msec increase in QTc; OR 1.083, CI [1.002, 1.171], p=0.04). INTERPRETATION QRS and QTc intervals are early markers for COVID-19 disease progression and mortality. ECG, a readily accessible tool, identifies cardiac involvement and may be used to predict disease course. FUNDING St. Francis Foundation.
Collapse
Affiliation(s)
- Avni Thakore
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
- Corresponding author.
| | - James Nguyen
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - Simcha Pollack
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - Stefan Muehlbauer
- Department of Emergency Medicine, St. Francis Hospital, The Heart Center –100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - Benjamin Chi
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - Derek Knight
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - Bhoomi Mehrotra
- Department of Hematology and Oncology, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn , New York 11576, United States
| | - Joshua Stern
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - J. Jane Cao
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - Charles Lucore
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| | - Joseph Levine
- Department of Cardiology and Research, St. Francis Hospital, The Heart Center – 100 Port Washington Blvd, Roslyn, New York 11576, United States
| |
Collapse
|
6
|
Orini M, Taggart P, Bhuva A, Roberts N, Di Salvo C, Yates M, Badiani S, Van Duijvenboden S, Lloyd G, Smith A, Lambiase PD. Direct in vivo assessment of global and regional mechanoelectric feedback in the intact human heart. Heart Rhythm 2021; 18:1406-1413. [PMID: 33932588 PMCID: PMC8353585 DOI: 10.1016/j.hrthm.2021.04.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023]
Abstract
Background Inhomogeneity of ventricular contraction is associated with sudden cardiac death, but the underlying mechanisms are unclear. Alterations in cardiac contraction impact electrophysiological parameters through mechanoelectric feedback. This has been shown to promote arrhythmias in experimental studies, but its effect in the in vivo human heart is unclear. Objective The purpose of this study was to quantify the impact of regional myocardial deformation provoked by a sudden increase in ventricular loading (aortic occlusion) on human cardiac electrophysiology. Methods In 10 patients undergoing open heart cardiac surgery, left ventricular (LV) afterload was modified by transient aortic occlusion. Simultaneous assessment of whole-heart electrophysiology and LV deformation was performed using an epicardial sock (240 electrodes) and speckle-tracking transesophageal echocardiography. Parameters were matched to 6 American Heart Association LV model segments. The association between changes in regional myocardial segment length and activation-recovery interval (ARI; a conventional surrogate for action potential duration) was studied using mixed-effect models. Results Increased ventricular loading reduced longitudinal shortening (P = .01) and shortened ARI (P = .02), but changes were heterogeneous between cardiac segments. Increased regional longitudinal shortening was associated with ARI shortening (effect size 0.20 [0.01–0.38] ms/%; P = .04) and increased local ARI dispersion (effect size –0.13 [–0.23 to –0.03] ms/%; P = .04). At the whole organ level, increased mechanical dispersion translated into increased dispersion of repolarization (correlation coefficient r = 0.81; P = .01). Conclusion Mechanoelectric feedback can establish a potentially proarrhythmic substrate in the human heart and should be considered to advance our understanding and prevention of cardiac arrhythmias.
Collapse
Affiliation(s)
- Michele Orini
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Peter Taggart
- Institute of Cardiovascular Science, University College London, London, United Kingdom.
| | - Anish Bhuva
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Neil Roberts
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Carmelo Di Salvo
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Martin Yates
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Sveeta Badiani
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | | | - Guy Lloyd
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Andrew Smith
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom
| | - Pier D Lambiase
- Electrophysiology Department, Barts Heart Centre at St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom
| |
Collapse
|
7
|
Vergara P, Altizio S, Falasconi G, Pannone L, Gulletta S, Della Bella P. Electrophysiological Substrate in Patients with Barlow's Disease. Arrhythm Electrophysiol Rev 2021; 10:33-37. [PMID: 33936741 PMCID: PMC8076976 DOI: 10.15420/aer.2020.29] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mitral valve prolapse (MVP) is the most common valvular heart disease, affecting 2-3% of the general population. Barlow's disease is a clinical syndrome characterised by MVP. Initially thought a benign condition, MVP is now recognised as a cause of sudden cardiac death and ventricular arrhythmias. The development of new imaging techniques has contributed recently to the identification of novel risk factors. Catheter ablation of ventricular arrhythmias in patients affected by MVP is traditionally considered challenging. In this review, the authors summarise the evidence on arrhythmogenesis in the context of MVP, along with risk stratification of sudden cardiac death and the available treatment options, including new catheter ablation techniques.
Collapse
Affiliation(s)
- Pasquale Vergara
- Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Savino Altizio
- Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Giulio Falasconi
- Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Luigi Pannone
- Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Simone Gulletta
- Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milano, Italy
| | - Paolo Della Bella
- Arrhythmia Unit and Electrophysiology Laboratories, IRCCS San Raffaele Scientific Institute, Milano, Italy
| |
Collapse
|
8
|
Peyronnet R, Solovyova O, Iribe G, Katsnelson LB. Editorial: Mechano-Calcium, Mechano-Electric, and Mechano-Metabolic Feedback Loops: Contribution to the Myocardial Contraction in Health and Diseases. Front Physiol 2021; 12:676826. [PMID: 33868032 PMCID: PMC8047467 DOI: 10.3389/fphys.2021.676826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 03/10/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Rémi Peyronnet
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg Bad Krozingen, Freiburg, Germany.,Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Olga Solovyova
- Institute of Immunology and Physiology, Russian Academy of Sciences, Ekaterinburg, Russia
| | - Gentaro Iribe
- Department of Physiology, Asahikawa Medical University, Asahikawa, Japan
| | - Leonid B Katsnelson
- Institute of Immunology and Physiology, Russian Academy of Sciences, Ekaterinburg, Russia
| |
Collapse
|
9
|
Koren O, Hakim R, Israeli A, Rozner E, Turgeman Y. Postoperative New-Onset Atrial Fibrillation following Noncardiac Operations: Prevalence, Complication, and Long-Term MACE. Cardiol Res Pract 2020; 2020:8156786. [PMID: 33123378 PMCID: PMC7582072 DOI: 10.1155/2020/8156786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Postoperative new-onset atrial fibrillation (POAF) is a common complication following cardiothoracic surgery, but little is known regarding its occurrence and outcome following noncardiothoracic surgery. This study was intended to examine the incidence of POAF in noncardiothoracic surgeries performed under general anesthesia and its effects on the length of hospitalization stay, short-term and long-term morbidity, and mortality. Methodology. We conducted a retrospective observational descriptive study. The study population consists of patients hospitalized in surgical wards from January 2014 to December 2017. Surgery was defined as noncardiac or thoracic procedure conducted under general anesthesia. RESULTS A total of 24,125 general anesthesia operations were performed at 7 surgical wards. About two-fifth of the operations (40%) were operated electively, and the rest underwent emergency surgery. The mean age was 63.78 ± 11.50, and more than half (56.9%) of the participants were female. The prevalence of POAF was 2.69 per 1000 adult patients (95% CI: 2.11-3.43) and vary significantly among wards. The highest prevalence was observed after hip fixation and laparotomy surgeries (54.9 and 26.7 per 1000 patients, respectively). The median length of hospitalization was significantly higher in POAF patients (21.0 vs. 4.8 days, p < 0.001). Patients who developed POAF had significantly higher mortality rates, both inhospital (200 vs. 7.56 deaths per 1000, p=0.001) and 1 year (261.5 vs. 33.3 per 1000, p=0.001, respectively). There was no significant association between outcome and treatment modalities such as rate or rhythm control and anticoagulant use. CONCLUSION New-onset AF following noncardiac surgery is rare, yet poses significant clinical implications, both immediate and long-term. POAF is associated with a longer length of hospitalization and a significantly higher mortality rate, both in short- and long-term.
Collapse
Affiliation(s)
- Ofir Koren
- Heart Institute, Emek Medical Center, Afula, Israel
- Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rony Hakim
- Anesthesia Department, Emek Medical Center, Afula, Israel
| | - Asaf Israeli
- Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ehud Rozner
- Anesthesia Department, Emek Medical Center, Afula, Israel
| | - Yoav Turgeman
- Heart Institute, Emek Medical Center, Afula, Israel
- Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| |
Collapse
|
10
|
Quinn TA, Kohl P. Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm. Physiol Rev 2020; 101:37-92. [PMID: 32380895 DOI: 10.1152/physrev.00036.2019] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ.
Collapse
Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Peter Kohl
- Department of Physiology and Biophysics and School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada; Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg/Bad Krozingen, Medical Faculty of the University of Freiburg, Freiburg, Germany; and CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| |
Collapse
|
11
|
Senturk SE, Icen YK, Koc AS, Donmez Y, Baykan AO, Unal İ, Sumbul H, Koc M. Evaluation of coronary sinus morphology by three-dimensional transthoracic echocardiography in patients undergoing electrophysiological study. J Arrhythm 2018; 34:626-631. [PMID: 30555606 PMCID: PMC6288552 DOI: 10.1002/joa3.12122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 08/23/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In this study, we aimed to evaluate the coronary sinus (CS) morphology with three-dimensional transthoracic echocardiography (3D-TTE) in patients with supraventricular tachycardia (SVT) who underwent electrophysiological study (EPS). METHODS This cross-sectional study was conducted with 187 patients who underwent EPS between November 2016 and April 2017. Patients were divided into three groups: atrioventricular nodal reentrant tachycardia (AVNRT) (n = 72), non-AVNRT SVT (n = 58), and normal EPS (n = 57). All patients were evaluated with electrocardiography, TTE, and 3D-TTE. RESULTS The CS diameter (CSD) and area (CSA) were found significantly lower in the normal EPS group than in the other groups. There was no significant difference in the CSD between AVNRT and non-AVNRT SVT groups. However, it was found that the CSA was significantly larger in the AVNRT group than in the non-AVNRT SVT group. In linear regression analysis, age and left atrial diameter were determined as independent predictor for CSD and CSA (P < 0.001 for each one). CONCLUSIONS The CSD and CSA assessed by 3D-TTE were different and dilated in the patients with SVT compared to those in the normal individuals. There was no significant difference in the CSD between the AVNRT and non-AVNRT SVT groups. However, the AVNRT group had a larger CSA than the non-AVNRT SVT group.
Collapse
Affiliation(s)
- Serhat Emre Senturk
- Adana Health Practices and Research Center Cardiology DepartmentHealth Sciences UniversityAdanaTurkey
| | - Yahya Kemal Icen
- Adana Health Practices and Research Center Cardiology DepartmentHealth Sciences UniversityAdanaTurkey
| | - Ayşe Selcan Koc
- Adana Health Practices and Research Center Radiology DepartmentHealth Sciences UniversityAdanaTurkey
| | - Yurdaer Donmez
- Adana Health Practices and Research Center Cardiology DepartmentHealth Sciences UniversityAdanaTurkey
| | - Ahmet Oytun Baykan
- Adana Health Practices and Research Center Cardiology DepartmentHealth Sciences UniversityAdanaTurkey
| | - İlker Unal
- Department of BiostatisticsFaculty of MedicineCukurova UniversityBalcali, Saricam, AdanaTurkey
| | - Hilmi Erdem Sumbul
- Internal Medicine DepartmentHealth Sciences University Adana City Education and Research HospitalAdanaTurkey
| | - Mevlüt Koc
- Adana Health Practices and Research Center Cardiology DepartmentHealth Sciences UniversityAdanaTurkey
| |
Collapse
|
12
|
Timmermann V, Dejgaard LA, Haugaa KH, Edwards AG, Sundnes J, McCulloch AD, Wall ST. An integrative appraisal of mechano-electric feedback mechanisms in the heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:404-417. [PMID: 28851517 DOI: 10.1016/j.pbiomolbio.2017.08.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 08/12/2017] [Accepted: 08/18/2017] [Indexed: 12/20/2022]
Abstract
Mechanically-induced alterations in cardiac electrophysiology are referred to as mechano-electric feedback (MEF), and play an important role in electrical regulation of cardiac performance. The influence of mechanical stress and strain on electrophysiology has been investigated at all levels, however the role of MEF in arrhythmia remains poorly understood. During the normal contraction of the heart, mechano-sensitive processes are an implicit component of cardiac activity. Under abnormal mechanical events, stretch-activated mechanisms may contribute to local or global changes in electrophysiology (EP). While such mechanisms have been hypothesised to be involved in mechanically-initiated arrhythmias, the details of these mechanisms and their importance remain elusive. We assess the theoretical role of stretch mechanisms using coupled models of cellular electrophysiology and sarcomere contraction dynamics. Using models of single ventricular myocytes, we first investigated the potential MEF contributions of stretch-activated currents (SAC), and stretch-induced myofilament calcium release, to test how strain and fibrosis may alter cellular electrophysiology. For all models investigated, SACs were alone not sufficient to create a pro-arrhythmic perturbation of the action potential with stretch. However, when combined with stretch-induced myofilament calcium release, the action potential could be shortened depending on the timing of the strain. This effect was highly model dependent, with a canine epicardial EP model being the most sensitive. These model results suggest that known mechanisms of mechano-electric coupling in cardiac myocyte may be sufficient to be pro-arrhythmic, but only in combination and under specific strain patterns.
Collapse
Affiliation(s)
- Viviane Timmermann
- Simula Research Laboratory, Martin Linges vei 25, Fornebu, 1364, Norway; Center for Cardiological Innovation, Songsvannsveien 9, Oslo, 0372, Norway; University California San Diego, 9500 Gilman Drive, La Jolla, CA, United States; University of Oslo, Gaustadallen 23 B, Oslo, 0373, Norway.
| | - Lars A Dejgaard
- Center for Cardiological Innovation, Songsvannsveien 9, Oslo, 0372, Norway; Department of Cardiology, Oslo University Hospital, Norway
| | - Kristina H Haugaa
- Center for Cardiological Innovation, Songsvannsveien 9, Oslo, 0372, Norway; Department of Cardiology, Oslo University Hospital, Norway
| | - Andrew G Edwards
- Simula Research Laboratory, Martin Linges vei 25, Fornebu, 1364, Norway; Center for Cardiological Innovation, Songsvannsveien 9, Oslo, 0372, Norway; University of Oslo, Gaustadallen 23 B, Oslo, 0373, Norway
| | - Joakim Sundnes
- Simula Research Laboratory, Martin Linges vei 25, Fornebu, 1364, Norway; Center for Cardiological Innovation, Songsvannsveien 9, Oslo, 0372, Norway; University of Oslo, Gaustadallen 23 B, Oslo, 0373, Norway
| | - Andrew D McCulloch
- University California San Diego, 9500 Gilman Drive, La Jolla, CA, United States
| | - Samuel T Wall
- Simula Research Laboratory, Martin Linges vei 25, Fornebu, 1364, Norway; Center for Cardiological Innovation, Songsvannsveien 9, Oslo, 0372, Norway.
| |
Collapse
|
13
|
Meijborg VMF, Belterman CNW, de Bakker JMT, Coronel R, Conrath CE. Mechano-electric coupling, heterogeneity in repolarization and the electrocardiographic T-wave. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:356-364. [PMID: 28527890 DOI: 10.1016/j.pbiomolbio.2017.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/11/2017] [Accepted: 05/15/2017] [Indexed: 11/28/2022]
Abstract
Stretch influences repolarization by mechano-electric coupling (MEC) and contributes to arrhythmogenesis. Although there is an abundance of research on electrophysiological effects of MEC, it is still unclear how MEC translates to the ECG. We aim to provide an overview of the MEC research focused on the ECG and the underlying changes in electrophysiology. In addition, we present new data on the effect of left ventricular pressure on the electrocardiographic T-wave. We show that an increase in left ventricular pressure leads to prolonged QT-intervals with increased amplitudes of the STT-segment. This corresponds to a prolongation in repolarization and an increased interventricular dispersion of repolarization. MEC is dependent on timing, intensity and modality of stretch and these three factors should be taken into account to analyse the effects of MEC on the heart and on the ECG. In addition, the deformation of the heart itself should be considered, since it influences the amplitude of the STT-segment. Because the electrocardiographic T-wave represents heterogeneity in repolarization, left ventricular pressure increases may have significant influence on the inducibility of (re-entrant) arrhythmias.
Collapse
Affiliation(s)
- V M F Meijborg
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands; Netherlands Heart Institute, Holland Heart House, Utrecht, The Netherlands.
| | - C N W Belterman
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands; Electrophysiology and Heart Modeling Institute LIRYC, Université Bordeaux, Bordeaux, France
| | - J M T de Bakker
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands; Netherlands Heart Institute, Holland Heart House, Utrecht, The Netherlands; Department of Medical Physiology, University of Utrecht, Utrecht, The Netherlands
| | - R Coronel
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands; Electrophysiology and Heart Modeling Institute LIRYC, Université Bordeaux, Bordeaux, France
| | - C E Conrath
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
| |
Collapse
|
14
|
Nikitina LV, Kopylova GV, Shchepkin DV, Nabiev SR, Bershitsky SY. Investigations of Molecular Mechanisms of Actin-Myosin Interactions in Cardiac Muscle. BIOCHEMISTRY (MOSCOW) 2016; 80:1748-63. [PMID: 26878579 DOI: 10.1134/s0006297915130106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The functional characteristics of cardiac muscle depend on the composition of protein isoforms in the cardiomyocyte contractile machinery. In the ventricular myocardium of mammals, several isoforms of contractile and regulatory proteins are expressed - two isoforms of myosin (V1 and V3) and three isoforms of tropomyosin chains (α, β, and κ). Expression of protein isoforms depends on the animal species, its age and hormonal status, and this can change with pathologies of the myocardium. Mutations in these proteins can lead to cardiomyopathies. The functional significance of the protein isoform composition has been studied mainly on intact hearts or on isolated preparations of myocardium, which could not provide a clear comprehension of the role of each particular isoform. Present-day experimental techniques such as an optical trap and in vitro motility assay make it possible to investigate the phenomena of interactions of contractile and regulatory proteins on the molecular level, thus avoiding effects associated with properties of a whole muscle or muscle tissue. These methods enable free combining of the isoforms to test the molecular mechanisms of their participation in the actin-myosin interaction. Using the optical trap and the in vitro motility assay, we have studied functional characteristics of the cardiac myosin isoforms, molecular mechanisms of the calcium-dependent regulation of actin-myosin interaction, and the role of myosin and tropomyosin isoforms in the cooperativity mechanisms in myocardium. The knowledge of molecular mechanisms underlying myocardial contractility and its regulation is necessary for comprehension of cardiac muscle functioning, its disorders in pathologies, and for development of approaches for their correction.
Collapse
Affiliation(s)
- L V Nikitina
- Institute of Immunology and Physiology, Ural Division of the Russian Academy of Sciences, Ekaterinburg, 620041, Russia.
| | | | | | | | | |
Collapse
|
15
|
Dokuchaev AD, Shikhaleva EV, Sulman TB, Vikulova NA, Nikitina LV, Katsnelson LB. Cooperativity in mechano-calcium feedbacks in the myocardium: Some conceptual discrepancies and overcoming inconsistency within the framework of a mathematical model. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s0006350916050043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
16
|
Pueyo E, Orini M, Rodríguez JF, Taggart P. Interactive effect of beta-adrenergic stimulation and mechanical stretch on low-frequency oscillations of ventricular action potential duration in humans. J Mol Cell Cardiol 2016; 97:93-105. [DOI: 10.1016/j.yjmcc.2016.05.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/21/2016] [Accepted: 05/03/2016] [Indexed: 01/27/2023]
|
17
|
Quinn TA, Kohl P. Rabbit models of cardiac mechano-electric and mechano-mechanical coupling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:110-22. [PMID: 27208698 PMCID: PMC5067302 DOI: 10.1016/j.pbiomolbio.2016.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/01/2016] [Indexed: 12/11/2022]
Abstract
Cardiac auto-regulation involves integrated regulatory loops linking electrics and mechanics in the heart. Whereas mechanical activity is usually seen as 'the endpoint' of cardiac auto-regulation, it is important to appreciate that the heart would not function without feed-back from the mechanical environment to cardiac electrical (mechano-electric coupling, MEC) and mechanical (mechano-mechanical coupling, MMC) activity. MEC and MMC contribute to beat-by-beat adaption of cardiac output to physiological demand, and they are involved in various pathological settings, potentially aggravating cardiac dysfunction. Experimental and computational studies using rabbit as a model species have been integral to the development of our current understanding of MEC and MMC. In this paper we review this work, focusing on physiological and pathological implications for cardiac function.
Collapse
Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada.
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Freiburg, Germany; National Heart and Lung Institute, Imperial College London, London, UK
| |
Collapse
|
18
|
Fluid Management, Volume Overload, and Gastrointestinal Tolerance in the Perioperative Period. CURRENT SURGERY REPORTS 2016. [DOI: 10.1007/s40137-016-0135-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
19
|
Exercise-induced ventricular re-polarisation changes in moderate congenital aortic valve stenosis. Cardiol Young 2016; 26:298-305. [PMID: 25704167 DOI: 10.1017/s1047951115000177] [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] [Indexed: 11/07/2022]
Abstract
UNLABELLED Introduction Pressure overload increases in patients with moderate aortic valvular stenosis during exercise. In the absence of symptoms, it remains difficult, however, to discriminate patients for surgery based only on pressure overload. Other parameters, such as the dispersion of ventricular re-polarisation (d-QT), which reportedly increases with the transvalvular pressure gradient, have not been fully studied in this condition. OBJECTIVE To determine the pattern of QT and d-QT response to exercise testing in children with moderate aortic valve stenosis in order to evaluate the impact of pressure overload from an electrophysiological perspective. Materials and methods In all, 15 patients were compared with 15 controls paired for age (14.8±2.5 versus 14.2±1.5 years old) and gender (66.7% male). All the patients underwent exercise stress testing with 12-lead electrocardiograph recording. QT was measured from the onset of QRS to the apex (QTa) at rest, at peak exercise, and at 1 and 3 minutes upon recovery. QT was corrected using the Fridericia equation, and d-QT was calculated. RESULTS Resting QTc was similar among the study groups, but increased significantly in study patients compared with the control group at maximal effort (p=0.004) and after 1 (p<0.001) and 3 (p<0.001) minutes of recovery. A significant association was identified between groups for d-QT (p=0.034), and post-hoc tests revealed a significant difference only at rest (p=0.001). CONCLUSIONS Ventricular re-polarisation abnormalities can be unmasked and highlighted by the assessment of electrical re-polarisation during exercise challenge in patients with asymptomatic moderate aortic valve stenosis. Using QT response to exercise could be beneficial for better optimisation of risk stratification in these patients.
Collapse
|
20
|
Effect of transcatheter aortic valve replacement on P-wave duration, P-wave dispersion and left atrial size. JOURNAL OF GERIATRIC CARDIOLOGY : JGC 2016; 12:613-7. [PMID: 26788037 PMCID: PMC4712366 DOI: 10.11909/j.issn.1671-5411.2015.06.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background P-wave dispersion (PWD), a measure of heterogeneity of atrial refractoriness, is defined as the difference between the maximum and minimum P-wave duration. In patients with severe aortic stenosis (AS), P-wave duration and PWD were shown to be increased, indicating atrial electrical remodeling. However, the effect of transcatheter aortic valve replacement (TAVR) on P-wave morphology has not been established yet. The aim of this study is to assess the short and long-term effects of TAVR with two types of bioprosthetic valves on P-wave duration and PWD in association with left atrial (LA) size. Methods Fifty-two (36 female) eligible patients in sinus rhythm who underwent transfemoral TAVR between June 01, 2012 and July 31, 2014 with either a Medtronic CoreValve (MCV) (n = 32) or an Edwards SAPIEN XT Valve (n = 20) were enrolled. Standard 12-lead electrocardiogram and echocardiographic evaluations were performed pre-procedurally, post-TAVR day one and 6 months post-TAVR. P-wave duration and PWD were measured and correlation analyses with echocardiographic variables were performed. Results P-wave duration and PWD were significantly decreased on post-TAVR day one (P < 0.05). They continued to decrease during the six month follow-up period, but were not significantly different from short-term values (P > 0.05). The decrease of LA diameter was found significant at the sixth-months of follow-up (P < 0.05). These changes were independent from the types of bioprosthetic valves implanted (P > 0.05). A positive correlation was detected between minimum P-wave duration and maximum aortic valve gradients at post-TAVR day one (r = 0.297, P = 0.032). Conclusions P-wave duration and PWD were significantly reduced early after TAVR indicating early reverse atrial electrical remodeling. Moreover, structural reverse remodeling of atrium was detected at the 6-months of follow-up. The effects of two types of bioprosthetic valves on atrial remodeling were similar.
Collapse
|
21
|
Haemers P, Sutherland G, Cikes M, Jakus N, Holemans P, Sipido KR, Willems R, Claus P. Further insights into blood pressure induced premature beats: Transient depolarizations are associated with fast myocardial deformation upon pressure decline. Heart Rhythm 2015; 12:2305-15. [DOI: 10.1016/j.hrthm.2015.06.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Indexed: 11/28/2022]
|
22
|
Hazim A, Belhamadia Y, Dubljevic S. Control of cardiac alternans in an electromechanical model of cardiac tissue. Comput Biol Med 2015; 63:108-17. [PMID: 26069933 DOI: 10.1016/j.compbiomed.2015.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 11/26/2022]
Abstract
Electrical alternations in cardiac action potential duration have been shown to be a precursor to arrhythmias and sudden cardiac death. Through the mechanism of excitation-contraction coupling, the presence of electrical alternans induces alternations in the heart muscle contractile activity. Also, contraction of cardiac tissue affects the process of cardiac electric wave propagation through the mechanism of the so-called mechanoelectrical feedback. Electrical excitation and contraction of cardiac tissue can be linked by an electromechanical model such as the Nash-Panfilov model. In this work, we explore the feasibility of suppressing cardiac alternans in the Nash-Panfilov model which is employed for small and large deformations. Several electrical pacing and mechanical perturbation feedback strategies are considered to demonstrate successful suppression of alternans on a one-dimensional cable. This is the first attempt to combine electrophysiologically relevant cardiac models of electrical wave propagation and contractility of cardiac tissue in a synergistic effort to suppress cardiac alternans. Numerical examples are provided to illustrate the feasibility and the effects of the proposed algorithms to suppress cardiac alternans.
Collapse
Affiliation(s)
- Azzam Hazim
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB Canada T6G 2V2
| | - Youssef Belhamadia
- Department of Biomedical Engineering, Department of Mathematics and Campus Saint-Jean, University of Alberta, AB Canada T6C 4G9
| | - Stevan Dubljevic
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB Canada T6G 2V4.
| |
Collapse
|
23
|
Modulation of the QT interval duration in hypertension with antihypertensive treatment. Hypertens Res 2015; 38:447-54. [DOI: 10.1038/hr.2015.30] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/27/2014] [Accepted: 11/12/2014] [Indexed: 11/08/2022]
|
24
|
Joshi KK, Tiru M, Chin T, Fox MT, Stefan MS. Postoperative atrial fibrillation in patients undergoing non-cardiac non-thoracic surgery: A practical approach for the hospitalist. Hosp Pract (1995) 2015; 43:235-244. [PMID: 26414594 PMCID: PMC4724415 DOI: 10.1080/21548331.2015.1096181] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
New postoperative atrial fibrillation (POAF) is the most common perioperative arrhythmia and its reported incidence ranges from 0.4 to 26% in patients undergoing non-cardiac non-thoracic surgery. The incidence varies according to patient characteristics such as age, presence of structural heart disease and other co-morbidities, as well as the type of surgery performed. POAF occurs as a consequence of adrenergic stimulation, systemic inflammation, or autonomic activation in the intra or postoperative period (e.g. due to pain, hypotension, infection) in the setting of a susceptible myocardium and other predisposing factors (e.g. electrolyte abnormalities). POAF develops between day 1 and day 4 post-surgery and it is often considered a self-limited entity. Its acute management involves many of the same strategies used in non-surgical patients but the optimal long-term management is challenging because of the limited available evidence. Several studies have shown an association between occurrence of POAF and in-hospital morbidity, mortality, and length of stay. Although, traditionally, POAF was considered to have a generally favorable long-term prognosis, recent data have shown an association with an increased risk of stroke at 1 year after hospitalization. It is unknown, however, whether strategies to prevent POAF or for rate/rhythm control when it does occur, lead to a reduction in morbidity or mortality. This suggests the need for future studies to better understand the risks associated with POAF and to determine optimal strategies to minimize long-term thromboembolic risks. In this article, we summarize the current knowledge on epidemiology, pathophysiology, and short- and long-term management of POAF after non-cardiac non-thoracic surgery with the goal of providing a practical approach to managing these patients for the non-cardiologist clinician.
Collapse
|
25
|
Pfeiffer ER, Tangney JR, Omens JH, McCulloch AD. Biomechanics of cardiac electromechanical coupling and mechanoelectric feedback. J Biomech Eng 2014; 136:021007. [PMID: 24337452 DOI: 10.1115/1.4026221] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/12/2013] [Indexed: 11/08/2022]
Abstract
Cardiac mechanical contraction is triggered by electrical activation via an intracellular calcium-dependent process known as excitation-contraction coupling. Dysregulation of cardiac myocyte intracellular calcium handling is a common feature of heart failure. At the organ scale, electrical dyssynchrony leads to mechanical alterations and exacerbates pump dysfunction in heart failure. A reverse coupling between cardiac mechanics and electrophysiology is also well established. It is commonly referred as cardiac mechanoelectric feedback and thought to be an important contributor to the increased risk of arrhythmia during pathological conditions that alter regional cardiac wall mechanics, including heart failure. At the cellular scale, most investigations of myocyte mechanoelectric feedback have focused on the roles of stretch-activated ion channels, though mechanisms that are independent of ionic currents have also been described. Here we review excitation-contraction coupling and mechanoelectric feedback at the cellular and organ scales, and we identify the need for new multicellular tissue-scale model systems and experiments that can help us to obtain a better understanding of how interactions between electrophysiological and mechanical processes at the cell scale affect ventricular electromechanical interactions at the organ scale in the normal and diseased heart.
Collapse
|
26
|
Bogossian H, Ninios I, Frommeyer G, Bandorski D, Eckardt L, Lemke B, Zarse M. U wave during supraventricular tachycardia: simulation of a long RP tachycardia and hiding the common type AVNRT. Ann Noninvasive Electrocardiol 2014; 20:292-5. [PMID: 25200520 DOI: 10.1111/anec.12190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The main tool for the differentiation of supraventricular tachycardia is the 12-lead electrocardiogram (ECG). Especially differentiating the atrioventricular nodal reentrant tachycardia (AVNRT) from the atrioventricular reentrant tachycardia (AVRT) due to concealed accessory pathway or from an atrial tachycardia (AT) is very important for catheter setting and ablation approach in an electrophysiological study. In our case we saw the occurrence of a U wave during tachycardia-simulating a pseudo P wave. This mimicked a long RP-tachycardia, although it was a common type AVNRT.
Collapse
Affiliation(s)
- Harilaos Bogossian
- Märkische Kliniken GmbH, Department of Cardiology and Angiology, Klinikum Lüdenscheid, Germany.,Department of Cardiology, University Witten/ Herdecke, Witten, Germany
| | - Ilias Ninios
- Märkische Kliniken GmbH, Department of Cardiology and Angiology, Klinikum Lüdenscheid, Germany
| | - Gerrit Frommeyer
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Dirk Bandorski
- Märkische Kliniken GmbH, Department of Cardiology and Angiology, Klinikum Lüdenscheid, Germany
| | - Lars Eckardt
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Germany
| | - Bernd Lemke
- Märkische Kliniken GmbH, Department of Cardiology and Angiology, Klinikum Lüdenscheid, Germany
| | - Markus Zarse
- Märkische Kliniken GmbH, Department of Cardiology and Angiology, Klinikum Lüdenscheid, Germany.,Department of Cardiology, University Witten/ Herdecke, Witten, Germany
| |
Collapse
|
27
|
Knöll R. A role for membrane shape and information processing in cardiac physiology. Pflugers Arch 2014; 467:167-73. [PMID: 25129123 PMCID: PMC4281353 DOI: 10.1007/s00424-014-1575-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/28/2014] [Accepted: 07/02/2014] [Indexed: 01/04/2023]
Abstract
While the heart is a dynamic organ and one of its major functions is to provide the organism with sufficient blood supply, the regulatory feedback systems, which allow adaptation to hemodynamic changes, remain not well understood. Our current description of mechanosensation focuses on stretch-sensitive ion channels, cytoskeletal components, structures such as the sarcomeric Z-disc, costameres, caveolae, or the concept of tensegrity, but these models appear incomplete as the remarkable plasticity of the myocardium in response to biomechanical stress and heart rate variations remains unexplained. Signaling activity at membranes depends on their geometric parameters such as surface area and curvature, which links shape to information processing. In the heart, continuous cycles of contraction and relaxation reshape membrane morphology and hence affect cardio-mechanic signaling. This article provides a brief review on current models of mechanosensation and focuses on how signaling, cardiac myocyte dynamics, and membrane shape interact and potentially give rise to a self-organized system that uses shape to sense the extra- and intracellular environment. This novel concept may help to explain how changes in frequency, and thus membrane shape, affect cardiac plasticity. One of the conclusions is that hypertrophy and associated fibrosis, which have been considered as necessary to cope with increased wall stress, can also be seen as part of complex feedback systems which use local membrane inhomogeneity in different cardiac cell types to influence whole organphysiology and which are predicted to fine-tune and thus regulate membrane-mediated signaling.
Collapse
Affiliation(s)
- Ralph Knöll
- Innovative Medicines and Early Development, Cardiovascular and Metabolic Diseases iMed, AstraZeneca Research and Development Mölndal, Pepparedsleden 1, SE-431 83, Mölndal, Sweden,
| |
Collapse
|
28
|
Living cardiac tissue slices: an organotypic pseudo two-dimensional model for cardiac biophysics research. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:314-27. [PMID: 25124067 DOI: 10.1016/j.pbiomolbio.2014.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 08/02/2014] [Indexed: 11/24/2022]
Abstract
Living cardiac tissue slices, a pseudo two-dimensional (2D) preparation, have received less attention than isolated single cells, cell cultures, or Langendorff-perfused hearts in cardiac biophysics research. This is, in part, due to difficulties associated with sectioning cardiac tissue to obtain live slices. With moderate complexity, native cell-types, and well-preserved cell-cell electrical and mechanical interconnections, cardiac tissue slices have several advantages for studying cardiac electrophysiology. The trans-membrane potential (Vm) has, thus far, mainly been explored using multi-electrode arrays. Here, we combine tissue slices with optical mapping to monitor Vm and intracellular Ca(2+) concentration ([Ca(2+)]i). This combination opens up the possibility of studying the effects of experimental interventions upon action potential (AP) and calcium transient (CaT) dynamics in 2D, and with relatively high spatio-temporal resolution. As an intervention, we conducted proof-of-principle application of stretch. Mechanical stimulation of cardiac preparations is well-established for membrane patches, single cells and whole heart preparations. For cardiac tissue slices, it is possible to apply stretch perpendicular or parallel to the dominant orientation of cells, while keeping the preparation in a constant focal plane for fluorescent imaging of in-slice functional dynamics. Slice-to-slice comparison furthermore allows one to assess transmural differences in ventricular tissue responses to mechanical challenges. We developed and tested application of axial stretch to cardiac tissue slices, using a manually-controlled stretching device, and recorded Vm and [Ca(2+)]i by optical mapping before, during, and after application of stretch. Living cardiac tissue slices, exposed to axial stretch, show an initial shortening in both AP and CaT duration upon stretch application, followed in most cases by a gradual prolongation of AP and CaT duration during stretch maintained for up to 50 min. After release of sustained stretch, AP duration (APD) and CaT duration reverted to shorter values. Living cardiac tissue slices are a promising experimental model for the study of cardiac mechano-electric interactions. The methodology described here can be refined to achieve more accurate control over stretch amplitude and timing (e.g. using a computer-controlled motorised stage, or by synchronising electrical and mechanical events) and through monitoring of regional tissue deformation (e.g. by adding motion tracking).
Collapse
|
29
|
Livneh A, Kimmel E, Kohut AR, Adam D. Extracorporeal acute cardiac pacing by High Intensity Focused Ultrasound. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:140-53. [DOI: 10.1016/j.pbiomolbio.2014.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 08/06/2014] [Indexed: 11/29/2022]
|
30
|
Fereniec M, Stix G, Kania M, Mroczka T, Maniewski R. An analysis of the U-wave and its relation to the T-wave in body surface potential maps for healthy subjects and MI patients. Ann Noninvasive Electrocardiol 2014; 19:145-56. [PMID: 24191849 PMCID: PMC6932608 DOI: 10.1111/anec.12110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND The aim of this study was to analyze the U-wave morphology and its relation to the T-wave in one group of healthy subjects and in two groups of myocardial infarction (MI) patients-with and without ventricular tachycardia (VT) episodes. The context of the U-wave origin was also discussed and the U-wave as a potential marker of VT was investigated. METHODS The study was carried out on three groups of subjects: 20 healthy subjects, 14 MI patients not at risk of VT, and 22 MI patients at risk of VT. The morphology of the repolarization phase was examined in the high-resolution body surface potential maps recorded from 64 surface ECG leads. The temporal and spatial distributions of several ECG parameters were studied. RESULTS The U-wave was present in almost all the studied subjects. The spatial heterogeneity and smooth change in both the T- and U-wave shapes on the entire torso were observed in all the studied groups. The statistical significance of discrimination between the MI patients without VT and MI patients with VT was observed for QRS interval, QT interval, U-wave integral, and normalized U-wave integral. CONCLUSIONS High-resolution measurement of body surface potentials and an advanced data analysis allow for a detailed description of U-wave morphology and its relation to the T-wave. This might be of value in discriminating intracardiac repolarization effects, mechano-electrical feedback, and arrhythmia risk stratification.
Collapse
Affiliation(s)
- Małgorzata Fereniec
- Department of Biophysical Measurements and ImagingNalecz Institute of Biocybernetics and Biomedical EngineeringPolish Academy of SciencesWarsawPoland
| | - Günter Stix
- Department of CardiologyMedical University of ViennaGeneral Hospital of ViennaViennaAustria
| | - Michał Kania
- Department of Biophysical Measurements and ImagingNalecz Institute of Biocybernetics and Biomedical EngineeringPolish Academy of SciencesWarsawPoland
| | - Tomasz Mroczka
- Department of Internal Medicine and CardiologyGeriatric Center WienerwaldViennaAustria
| | - Roman Maniewski
- Department of Biophysical Measurements and ImagingNalecz Institute of Biocybernetics and Biomedical EngineeringPolish Academy of SciencesWarsawPoland
| |
Collapse
|
31
|
The importance of non-uniformities in mechano-electric coupling for ventricular arrhythmias. J Interv Card Electrophysiol 2013; 39:25-35. [DOI: 10.1007/s10840-013-9852-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 10/16/2013] [Indexed: 12/31/2022]
|
32
|
WAXMAN MENASHEB, KIRSH JOELA, YAO LOUIS, CAMERON DOUGLASA, ASTA JOHNA. Slowing of the Atrial Flutter Rate During 1:1 Atrioventricular Conduction in Humans and Dogs: An Effect Mediated Through Atrial Pressure and Volume. J Cardiovasc Electrophysiol 2013. [DOI: 10.1111/j.1540-8167.1992.tb01935.x] [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] [Indexed: 11/28/2022]
|
33
|
MYERBURG ROBERTJ, KESSLER KENNETHM, KIMURA SHINICHI, CASTELLANOS AGUSTIN. Sudden Cardiac Death: Future Approaches Based on Identification and Control of Transient Risk Factors. J Cardiovasc Electrophysiol 2013. [DOI: 10.1111/j.1540-8167.1992.tb01941.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
34
|
Adeniran I, Hancox JC, Zhang H. In silico investigation of the short QT syndrome, using human ventricle models incorporating electromechanical coupling. Front Physiol 2013; 4:166. [PMID: 23847545 PMCID: PMC3701879 DOI: 10.3389/fphys.2013.00166] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 06/14/2013] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Genetic forms of the Short QT Syndrome (SQTS) arise due to cardiac ion channel mutations leading to accelerated ventricular repolarization, arrhythmias and sudden cardiac death. Results from experimental and simulation studies suggest that changes to refractoriness and tissue vulnerability produce a substrate favorable to re-entry. Potential electromechanical consequences of the SQTS are less well-understood. The aim of this study was to utilize electromechanically coupled human ventricle models to explore electromechanical consequences of the SQTS. METHODS AND RESULTS The Rice et al. mechanical model was coupled to the ten Tusscher et al. ventricular cell model. Previously validated K(+) channel formulations for SQT variants 1 and 3 were incorporated. Functional effects of the SQTS mutations on [Ca(2+)] i transients, sarcomere length shortening and contractile force at the single cell level were evaluated with and without the consideration of stretch-activated channel current (I sac). Without I sac, at a stimulation frequency of 1Hz, the SQTS mutations produced dramatic reductions in the amplitude of [Ca(2+)] i transients, sarcomere length shortening and contractile force. When I sac was incorporated, there was a considerable attenuation of the effects of SQTS-associated action potential shortening on Ca(2+) transients, sarcomere shortening and contractile force. Single cell models were then incorporated into 3D human ventricular tissue models. The timing of maximum deformation was delayed in the SQTS setting compared to control. CONCLUSION The incorporation of I sac appears to be an important consideration in modeling functional effects of SQT 1 and 3 mutations on cardiac electro-mechanical coupling. Whilst there is little evidence of profoundly impaired cardiac contractile function in SQTS patients, our 3D simulations correlate qualitatively with reported evidence for dissociation between ventricular repolarization and the end of mechanical systole.
Collapse
Affiliation(s)
- Ismail Adeniran
- Computational Biology, Biological Physics Group, School of Physics and Astronomy, The University of Manchester Manchester, UK
| | | | | |
Collapse
|
35
|
Weise LD, Panfilov AV. A discrete electromechanical model for human cardiac tissue: effects of stretch-activated currents and stretch conditions on restitution properties and spiral wave dynamics. PLoS One 2013; 8:e59317. [PMID: 23527160 PMCID: PMC3602082 DOI: 10.1371/journal.pone.0059317] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 02/13/2013] [Indexed: 11/24/2022] Open
Abstract
We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006) and tension development (adjusted Niederer, Hunter, Smith, 2006 model) with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material). Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning.
Collapse
Affiliation(s)
- Louis D Weise
- Department of Theoretical Biology, Utrecht University, Utrecht, The Netherlands.
| | | |
Collapse
|
36
|
Quinn TA, Kohl P. Combining wet and dry research: experience with model development for cardiac mechano-electric structure-function studies. Cardiovasc Res 2013; 97:601-11. [PMID: 23334215 PMCID: PMC3583260 DOI: 10.1093/cvr/cvt003] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 01/08/2013] [Accepted: 01/15/2013] [Indexed: 11/17/2022] Open
Abstract
Since the development of the first mathematical cardiac cell model 50 years ago, computational modelling has become an increasingly powerful tool for the analysis of data and for the integration of information related to complex cardiac behaviour. Current models build on decades of iteration between experiment and theory, representing a collective understanding of cardiac function. All models, whether computational, experimental, or conceptual, are simplified representations of reality and, like tools in a toolbox, suitable for specific applications. Their range of applicability can be explored (and expanded) by iterative combination of 'wet' and 'dry' investigation, where experimental or clinical data are used to first build and then validate computational models (allowing integration of previous findings, quantitative assessment of conceptual models, and projection across relevant spatial and temporal scales), while computational simulations are utilized for plausibility assessment, hypotheses-generation, and prediction (thereby defining further experimental research targets). When implemented effectively, this combined wet/dry research approach can support the development of a more complete and cohesive understanding of integrated biological function. This review illustrates the utility of such an approach, based on recent examples of multi-scale studies of cardiac structure and mechano-electric function.
Collapse
Affiliation(s)
- T Alexander Quinn
- National Heart and Lung Institute, Imperial College London, Heart Science Centre, Harefield UB9 6JH, UK.
| | | |
Collapse
|
37
|
Barrabés JA, Figueras J, Candell-Riera J, Agulló L, Inserte J, Garcia-Dorado D. La distensión de la región isquémica predice una mayor inducibilidad de fibrilación ventricular tras la oclusión coronaria en el modelo porcino. Rev Esp Cardiol 2013. [DOI: 10.1016/j.recesp.2012.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
38
|
Puglisi JL, Negroni JA, Chen-Izu Y, Bers DM. The force-frequency relationship: insights from mathematical modeling. ADVANCES IN PHYSIOLOGY EDUCATION 2013; 37:28-34. [PMID: 23471245 PMCID: PMC3776472 DOI: 10.1152/advan.00072.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 10/31/2012] [Indexed: 06/01/2023]
Abstract
The force-frequency relationship has intrigued researchers since its discovery by Bowditch in 1871. Many attempts have been made to construct mathematical descriptions of this phenomenon, beginning with the simple formulation of Koch-Wesser and Blinks in 1963 to the most sophisticated ones of today. This property of cardiac muscle is amplified by β-adrenergic stimulation, and, in a coordinated way, the neurohumoral state alters both frequency (acting on the sinoatrial node) as well as force generation (modifying ventricular myocytes). This synchronized tuning is needed to meet new metabolic demands. Cardiac modelers have already linked mechanical and electrical activity in their formulations and showed how those activities feedback on each other. However, now it is necessary to include neurological control to have a complete description of heart performance, especially when changes in frequency are involved. Study of arrhythmias (or antiarrhythmic drugs) based on mathematical models should incorporate this effect to make useful predictions or point out potential pharmaceutical targets.
Collapse
Affiliation(s)
- Jose L Puglisi
- Department of Pharmacology, University of California, Davis, CA 95616, USA.
| | | | | | | |
Collapse
|
39
|
Adeniran I, Hancox JC, Zhang H. Effect of cardiac ventricular mechanical contraction on the characteristics of the ECG: A simulation study. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jbise.2013.612a007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
40
|
Distension of the ischemic region predicts increased ventricular fibrillation inducibility following coronary occlusion in swine. ACTA ACUST UNITED AC 2012; 66:171-6. [PMID: 24775450 DOI: 10.1016/j.rec.2012.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 08/01/2012] [Indexed: 11/21/2022]
Abstract
INTRODUCTION AND OBJECTIVES Distension of the ischemic region has been related to an increased incidence of spontaneous ventricular arrhythmias following coronary occlusion. This study analyzed whether regional ischemic distension predicts increased ventricular fibrillation inducibility after coronary occlusion in swine. METHODS In 18 anesthetized, open-chest pigs, the left anterior descending coronary artery was ligated for 60 min. Myocardial segment length in the ischemic region was monitored by means of ultrasonic crystals. Programmed stimulation was applied at baseline and then continuously between 10 and 60 min after coronary occlusion. RESULTS Coronary occlusion induced a rapid increase in end-diastolic length in the ischemic region, which reached 109.4% (0.9%) of baseline values 10 min after occlusion (P<.001). On average, 6.6 (0.5) stimulation protocols were completed and 5.4 (0.6) ventricular fibrillation episodes induced between 10 and 60 min of coronary occlusion. Neither baseline serum potassium levels nor the size of the ischemic region were significantly related to ventricular fibrillation inducibility. In contrast, the increase in end-diastolic length 10 min after coronary occlusion was associated directly (r=0.67; P=.002) with the number of induced ventricular fibrillation episodes and inversely (r=-0.55; P=.018) with the number of extrastimuli needed for ventricular fibrillation induction. CONCLUSIONS Regional ischemic expansion predicts increased ventricular fibrillation inducibility following coronary occlusion. These results highlight the potential influence of mechanical factors, acting not only on the triggers but also on the substrate, in the genesis of malignant ventricular arrhythmias during acute ischemia.
Collapse
|
41
|
|
42
|
Markhasin VS, Balakin AA, Katsnelson LB, Konovalov P, Lookin ON, Protsenko Y, Solovyova O. Slow force response and auto-regulation of contractility in heterogeneous myocardium. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:305-18. [DOI: 10.1016/j.pbiomolbio.2012.08.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 08/09/2012] [Indexed: 11/25/2022]
|
43
|
Quinn TA, Kohl P. Mechano-sensitivity of cardiac pacemaker function: pathophysiological relevance, experimental implications, and conceptual integration with other mechanisms of rhythmicity. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:257-68. [PMID: 23046620 PMCID: PMC3526794 DOI: 10.1016/j.pbiomolbio.2012.08.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 08/09/2012] [Indexed: 12/11/2022]
Abstract
Cardiac pacemaker cells exhibit spontaneous, rhythmic electrical excitation, termed automaticity. This automatic initiation of action potentials requires spontaneous diastolic depolarisation, whose rate determines normal rhythm generation in the heart. Pacemaker mechanisms have been split recently into: (i) cyclic changes in trans-sarcolemmal ion flows (termed the ‘membrane-clock’), and (ii) rhythmic intracellular calcium cycling (the ‘calcium-clock’). These two ‘clocks’ undoubtedly interact, as trans-sarcolemmal currents involved in pacemaking include calcium-carrying mechanisms, while intracellular calcium cycling requires trans-sarcolemmal ion flux as the mechanism by which it affects membrane potential. The split into separate ‘clocks’ is, therefore, somewhat arbitrary. Nonetheless, the ‘clock’ metaphor has been conceptually stimulating, in particular since there is evidence to support the view that either ‘clock’ could be sufficient in principle to set the rate of pacemaker activation. Of course, the same has also been shown for sub-sets of ‘membrane-clock’ ion currents, illustrating the redundancy of mechanisms involved in maintaining such basic functionality as the heartbeat, a theme that is common for vital physiological systems. Following the conceptual path of identifying individual groups of sub-mechanisms, it is important to remember that the heart is able to adapt pacemaker rate to changes in haemodynamic load, even after isolation or transplantation, and on a beat-by-beat basis. Neither the ‘membrane-’ nor the ‘calcium-clock’ do, as such, inherently account for this rapid adaptation to circulatory demand (cellular Ca2+ balance changes over multiple beats, while variation of sarcolemmal ion channel presence takes even longer). This suggests that a third set of mechanisms must be involved in setting the pace. These mechanisms are characterised by their sensitivity to the cyclically changing mechanical environment, and – in analogy to the above terminology – this might be considered a ‘mechanics-clock’. In this review, we discuss possible roles of mechano-sensitive mechanisms for the entrainment of membrane current dynamics and calcium-handling. This can occur directly via stretch-activation of mechano-sensitive ion channels in the sarcolemma and/or in intracellular membrane compartments, as well as by modulation of ‘standard’ components of the ‘membrane-’ or ‘calcium-clock’. Together, these mechanisms allow rapid adaptation to changes in haemodynamic load, on a beat-by-beat basis. Additional relevance arises from the fact that mechano-sensitivity of pacemaking may help to explain pacemaker dysfunction in mechanically over- or under-loaded tissue. As the combined contributions of the various underlying oscillatory mechanisms are integrated at the pacemaker cell level into a single output – a train of pacemaker action potentials – we will not adhere to a metaphor that implies separate time-keeping units (‘clocks’), and rather focus on cardiac pacemaking as the result of interactions of a set of coupled oscillators, whose individual contributions vary depending on the pathophysiological context. We conclude by considering the utility and limitations of viewing the pacemaker as a coupled system of voltage-, calcium-, and mechanics-modulated oscillators that, by integrating a multitude of inputs, offers the high level of functional redundancy that is vitally important for cardiac automaticity.
Collapse
Affiliation(s)
- T Alexander Quinn
- National Heart and Lung Institute, Imperial College London, London, UK.
| | | |
Collapse
|
44
|
Hermeling E, Delhaas T, Prinzen FW, Kuijpers NHL. Mechano-electrical feedback explains T-wave morphology and optimizes cardiac pump function: insight from a multi-scale model. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:359-71. [PMID: 22835663 DOI: 10.1016/j.pbiomolbio.2012.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 11/17/2022]
Abstract
In the ECG, T- and R-wave are concordant during normal sinus rhythm (SR), but discordant after a period of ventricular pacing (VP). Experiments showed that the latter phenomenon, called T-wave memory, is mediated by a mechanical stimulus. By means of a mathematical model, we investigated the hypothesis that slow acting mechano-electrical feedback (MEF) explains T-wave memory. In our model, electromechanical behavior of the left ventricle (LV) was simulated using a series of mechanically and electrically coupled segments. Each segment comprised ionic membrane currents, calcium handling, and excitation-contraction coupling. MEF was incorporated by locally adjusting conductivity of L-type calcium current (g(CaL)) to local external work. In our set-up, g(CaL) could vary up to 25%, 50%, 100% or unlimited amount around its default value. Four consecutive simulations were performed: normal SR (with MEF), acute VP, sustained VP (with MEF), and acutely restored SR. MEF led to T-wave concordance in normal SR and to discordant T-waves acutely after restoring SR. Simulated ECGs with a maximum of 25-50% adaptation closely resembled those during T-wave memory experiments in vivo and also provided the best compromise between optimal systolic and diastolic function. In conclusion, these simulation results indicate that slow acting MEF in the LV can explain a) the relatively small differences in systolic shortening and mechanical work during SR, b) the small dispersion in repolarization time, c) the concordant T-wave during SR, and d) T-wave memory. The physiological distribution in electrophysiological properties, reflected by the concordant T-wave, may serve to optimize cardiac pump function.
Collapse
Affiliation(s)
- Evelien Hermeling
- Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands.
| | | | | | | |
Collapse
|
45
|
Opthof T, Sutton P, Coronel R, Wright S, Kallis P, Taggart P. The Association of Abnormal Ventricular Wall Motion and Increased Dispersion of Repolarization in Humans is Independent of the Presence of Myocardial Infarction. Front Physiol 2012; 3:235. [PMID: 22783201 PMCID: PMC3388480 DOI: 10.3389/fphys.2012.00235] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Accepted: 06/11/2012] [Indexed: 11/13/2022] Open
Abstract
Abnormal ventricular wall motion is a strong clinical predictor of sudden, arrhythmic, cardiac death. Dispersion in repolarization is a prerequisite for the initiation of re-entrant arrhythmia. We hypothesize that regionally decreased wall motion is associated with heterogeneity of repolarization. We measured local activation times, activation-recovery intervals (ARIs, surrogate for action potential duration), and repolarization times using a multielectrode grid at nine segments on the left ventricular epicardium in 23 patients undergoing coronary artery surgery. Regional wall motion was simultaneously assessed using intraoperative transesophageal echocardiography. Three groups were discriminated: (1) Patients with normal wall motion (n = 11), (2) Patients with one or more hypokinetic segments (n = 6), (3) Patients with one or more akinetic or dyskinetic segments (n = 6). The average ARI was similar in all groups (251 ± 3.7 ms, ±SEM). Dispersion of ARIs between the nine segments was significantly increased in the hypokinetic (84 ± 7.4 ms, p < 0.005) and akinetic/dyskinetic group (94 ± 3.5 ms, p < 0.0005) compared with the normal group (49 ± 5.1 ms), independent from the presence of myocardial infarction. Repolarization heterogeneity occurred primarily in the normally contracting regions of the hearts with abnormal wall motion. An almost maximal increased dispersion of repolarization was observed when there was only a single hypokinetic segment. We conclude that inhomogeneous wall motion abnormality of even moderate severity is associated with increased repolarization inhomogeneity, independent from the presence of infarction.
Collapse
Affiliation(s)
- Tobias Opthof
- Experimental Cardiology Group, Center for Heart Failure Research, Academic Medical Center Amsterdam, Netherlands
| | | | | | | | | | | |
Collapse
|
46
|
Duverger JE, Béland J, Maguy A, Adegbindin MM, Comtois P. Fluorescence-based system for measurement of electrophysiological changes in stretched cultured cardiomyocytes. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:35-8. [PMID: 22254244 DOI: 10.1109/iembs.2011.6089890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acute or sustained stretch of cardiac tissue is known to play a key role in arrhythmogenesis. Using a fluorescence approach, we designed a system measuring calcium transients and transmembrane potential changes in monolayers of cultured cardiomyocytes under uniaxial elongation and electrical stimulation. Cardiac myocytes are seeded on a rectangular PDMS template held and stretched by a motorized linear guide system. Electrical stimulation is performed with two parallel carbon electrodes supplied by amplified pulses from a digital-to-analog converter. The cells are stained with either voltage- or calcium-sensitive dye (di-4-ANEPPS and Fluo-4 AM respectively). The two available excitation light sources are both current-controlled LED arrays (λ = 523 ± 45 nm for di-4-ANEPPS and λ = 505 ± 15 nm for Fluo-4 AM). The filtered emitted fluorescence (λ > 610 nm for di-4-ANEPPS and λ = 535 ± 25 nm for Fluo-4 AM) is transduced to current with a photodiode, converted to amplified voltage signals and digitized. The design and preliminary validation results are presented.
Collapse
|
47
|
Wang W, Buehler D, Martland AM, Feng XD, Wang YJ. Left atrial wall tension directly affects the restoration of sinus rhythm after Maze procedure. Eur J Cardiothorac Surg 2011; 40:77-82. [DOI: 10.1016/j.ejcts.2010.10.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 09/30/2010] [Accepted: 10/01/2010] [Indexed: 11/27/2022] Open
|
48
|
Chelazzi C, Villa G, De Gaudio AR. Postoperative atrial fibrillation. ISRN CARDIOLOGY 2011; 2011:203179. [PMID: 22347631 PMCID: PMC3262508 DOI: 10.5402/2011/203179] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 03/28/2011] [Indexed: 01/19/2023]
Abstract
Postoperative atrial fibrillation (POAF) is common among surgical patients and associated with a worse outcome. Pathophysiology of POAF is not fully disclosed, and several perioperative factors could be involved. Direct cardiac stimulation from perioperative use of catecholamines or increased sympathetic outflow from volume loss/anaemia/pain may play a role. Metabolic alterations, such as hypo-/hyperglycaemia and electrolyte disturbances, may also contribute to POAF. Moreover, inflammation, both systemic and local, may play a role in its pathogenesis. Strategies to prevent POAF aim at reducing its incidence and ameliorate global outcome of surgical patients. Nonpharmacological prophylaxis includes an adequate control of postoperative pain, the use of thoracic epidural analgesia, optimization of perioperative oxygen delivery, and, possibly, modulation of surgery-associated inflammatory response with immunonutrition and antioxidants. Perioperative potassium and magnesium depletion should be corrected. The impact of those interventions on patients outcome needs to be further investigated.
Collapse
Affiliation(s)
- C Chelazzi
- Section of Anesthesiology and Intensive Care, Department of Critical Care, University of Florence, 50121 Florence, Italy
| | | | | |
Collapse
|
49
|
|
50
|
Patrick SM, White E, Shiels HA. Mechano-electric feedback in the fish heart. PLoS One 2010; 5:e10548. [PMID: 20479879 PMCID: PMC2866336 DOI: 10.1371/journal.pone.0010548] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 04/09/2010] [Indexed: 12/05/2022] Open
Abstract
Background Mechanoelectric feedback (MEF) describes the modulation of electrical activity by mechanical activity. This may occur via the activation of mechanosensitive ion channels (MSCs). MEF has not previously been investigated in fish ventricular tissue even though fish can greatly increase ventricular end diastolic volume during exercise which should therefore provide a powerful mechanical stimulus for MEF. Methodology/Principal Finding When the ventricles of extrinsically paced, isolated working trout hearts were dilated by increasing afterload, monophasic action potential (MAP) duration was significantly shortened at 25% repolarisation, unaltered at 50% repolarisation and significantly lengthened at 90% repolarisation. This observation is consistent with the activation of cationic non-selective MSCs (MSCNSs). We then cloned the trout ortholog of TRPC1, a candidate MSCNS and confirmed its presence in the trout heart. Conclusions/Significance Our results have validated the use of MAP technology for the fish heart and suggest that, in common with amphibians and mammals, MEF operates in fish ventricular myocardium, possibly via the activation of mechanosensitive TRPC1 ion channels.
Collapse
Affiliation(s)
- Simon M Patrick
- Faculty of Life Sciences, University of Manchester, Manchester, England.
| | | | | |
Collapse
|