1
|
Kaufmann DK, Raczak G, Szwoch M, Wabich E, Świątczak M, Daniłowicz-Szymanowicz L. Baroreflex sensitivity but not microvolt T-wave alternans can predict major adverse cardiac events in ischemic heart failure. Cardiol J 2022; 29:1004-1012. [PMID: 33001423 PMCID: PMC9788737 DOI: 10.5603/cj.a2020.0129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/23/2020] [Accepted: 08/28/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Major adverse cardiovascular events (MACE) constitutes the main cause of morbidity and mortality in ischemic heart failure (HF) patients. The prognostic value of the autonomic nervous system parameters and microvolt T-wave alternans (MTWA) in this issue has not been identified to date. The aim herein, was to assess the usefulness of the abovementioned parameters in the prediction of MACE in HF patients with left ventricular systolic dysfunction of ischemic origin. METHODS Baroreflex sensitivity (BRS), heart rate variability (HRV), MTWA and other well-known clinical parameters were analyzed in 188 ischemic HF outpatients with left ventricular ejection fraction (LVEF) ≤ 50%. During 34 (14-71) months of follow-up, 56 (30%) endpoints were noted. RESULTS Univariate Cox analyses revealed BRS (but not HRV), MTWA, age, New York Heart Association functional class III, LVEF, implantable cardioverter-defibrillator presence, use of diuretics and antiarrhythmic drugs, diabetes, and kidney insufficiency were defined as significant predictors of MACE. Pre-specified cut-off values for MACE occurrence for the aforementioned continuous parameters (age, LVEF, and BRS) were: ≥ 72 years, ≤ 33%, and ≤ 3 ms/mmHg, respectively. In a multivariate Cox analysis only BRS (HR 2.97, 95% CI 1.35-6.36, p < 0.006), and LVEF (HR 1.98, 95% CI 0.61-4.52, p < 0.038) maintained statistical significance in the prediction of MACE. CONCLUSIONS Baroreflex sensitivity and LVEF are independent of other well-known clinical parameters in the prediction of MACE in patients with HF of ischemic origin and LVEF up to 50%. BRS ≤ 3 ms/mmHg and LVEF ≤ 33% identified individuals with the highest probability of MACE during the follow-up period.
Collapse
|
2
|
Millet J, Aguilar-Sanchez Y, Kornyeyev D, Bazmi M, Fainstein D, Copello JA, Escobar AL. Thermal modulation of epicardial Ca2+ dynamics uncovers molecular mechanisms of Ca2+ alternans. J Gen Physiol 2021; 153:211659. [PMID: 33410862 PMCID: PMC7797898 DOI: 10.1085/jgp.202012568] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 11/02/2020] [Accepted: 11/30/2020] [Indexed: 01/16/2023] Open
Abstract
Ca2+ alternans (Ca-Alts) are alternating beat-to-beat changes in the amplitude of Ca2+ transients that frequently occur during tachycardia, ischemia, or hypothermia that can lead to sudden cardiac death. Ca-Alts appear to result from a variation in the amount of Ca2+ released from the sarcoplasmic reticulum (SR) between two consecutive heartbeats. This variable Ca2+ release has been attributed to the alternation of the action potential duration, delay in the recovery from inactivation of RYR Ca2+ release channel (RYR2), or an incomplete Ca2+ refilling of the SR. In all three cases, the RYR2 mobilizes less Ca2+ from the SR in an alternating manner, thereby generating an alternating profile of the Ca2+ transients. We used a new experimental approach, fluorescence local field optical mapping (FLOM), to record at the epicardial layer of an intact heart with subcellular resolution. In conjunction with a local cold finger, a series of images were recorded within an area where the local cooling induced a temperature gradient. Ca-Alts were larger in colder regions and occurred without changes in action potential duration. Analysis of the change in the enthalpy and Q10 of several kinetic processes defining intracellular Ca2+ dynamics indicated that the effects of temperature change on the relaxation of intracellular Ca2+ transients involved both passive and active mechanisms. The steep temperature dependency of Ca-Alts during tachycardia suggests Ca-Alts are generated by insufficient SERCA-mediated Ca2+ uptake into the SR. We found that Ca-Alts are heavily dependent on intra-SR Ca2+ and can be promoted through partial pharmacologic inhibition of SERCA2a. Finally, the FLOM experimental approach has the potential to help us understand how arrhythmogenesis correlates with the spatial distribution of metabolically impaired myocytes along the myocardium.
Collapse
Affiliation(s)
- Jose Millet
- Institute of Information and Communication Technologies, Universitat Politècnica de València and Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares, Valencia, Spain
| | - Yuriana Aguilar-Sanchez
- Department of Physiology and Biophysics, School of Medicine, Rush University Medical Center, Chicago, IL.,School of Natural Sciences, University of California, Merced, Merced, CA
| | - Dmytro Kornyeyev
- Department of Bioengineering, School of Engineering, University of California Merced, Merced, CA
| | - Maedeh Bazmi
- School of Natural Sciences, University of California, Merced, Merced, CA
| | - Diego Fainstein
- Facultad de Ingeniería, Universidad Nacional de Entre Ríos, Entre Ríos, Argentina.,Department of Bioengineering, School of Engineering, University of California Merced, Merced, CA
| | - Julio A Copello
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL
| | - Ariel L Escobar
- Department of Bioengineering, School of Engineering, University of California Merced, Merced, CA
| |
Collapse
|
3
|
Sudden Cardiac Death in Patients with Heart Disease and Preserved Systolic Function: Current Options for Risk Stratification. J Clin Med 2021; 10:jcm10091823. [PMID: 33922111 PMCID: PMC8122448 DOI: 10.3390/jcm10091823] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 12/26/2022] Open
Abstract
Sudden cardiac death (SCD) is the leading cause of cardiovascular mortality in patients with coronary artery disease without severe systolic dysfunction and in heart failure with preserved ejection fraction. From a global health perspective, while risk may be lower, the absolute number of SCDs in patients with left ventricle ejection fraction >35% is higher than in those with severely reduced left ventricle ejection fraction (defined as ≤35%). Despite these observations and the high amount of available data, to date there are no clear recommendations to reduce the sudden cardiac death burden in the population with mid-range or preserved left ventricle ejection fraction. Ongoing improvements in risk stratification based on electrophysiological and imaging techniques point towards a more precise identification of patients who would benefit from ICD implantation, which is still an unmet need in this subset of patients. The aim of this review is to provide a state-of-the-art approach in sudden cardiac death risk stratification of patients with mid-range and preserved left ventricular ejection fraction and one of the following etiologies: ischemic cardiomyopathy, heart failure, atrial fibrillation or myocarditis.
Collapse
|
4
|
Primary Prevention Implantable Cardioverter-Defibrillator Therapy in Heart Failure with Recovered Ejection Fraction. J Card Fail 2021; 27:585-596. [PMID: 33636331 DOI: 10.1016/j.cardfail.2021.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/26/2021] [Accepted: 02/07/2021] [Indexed: 11/21/2022]
Abstract
Given recent advances in both pharmacologic and nonpharmacologic strategies for improving outcomes related to chronic systolic heart failure, heart failure with recovered ejection fraction (HFrecEF) is now recognized as a distinct clinical entity with increasing prevalence. In many patients who once had an indication for active implantable cardioverter-defibrillator (ICD) therapy, questions remain regarding the usefulness of this primary prevention strategy to protect against syncope and cardiac arrest after they have achieved myocardial recovery. Early, small studies provide convincing evidence for continued guideline-directed medical therapy (GDMT) in segments of the HFrecEF population to promote persistent left ventricular myocardial recovery. Retrospective data suggest that the risk of sudden cardiac death is lower, but still present, in HFrecEF as compared with HF with reduced ejection fraction, with reports of up to 5 appropriate ICD therapies delivered per 100 patient-years. The usefulness of continued ICD therapy is weighed against the unfavorable effects of this strategy, which include a cumulative risk of infection, inappropriate discharge, and patient-level anxiety. Historically, many surrogate measures for risk stratification have been explored, but few have demonstrated efficacy and widespread availability. We found that the available data to inform decisions surrounding the continued use of active ICD therapies in this population are incomplete, and more advanced tools such as genetic testing, evaluation of high-risk structural cardiomyopathies (such as noncompaction), and cardiac magnetic resonance imaging have emerged as vital in risk stratification. Clinicians and patients should engage in shared decision-making to evaluate the appropriateness of active ICD therapy for any given individual. In this article, we explore the definition of HFrecEF, data underlying continuation of guideline-directed medical therapy in patients who have achieved left ventricular ejection fraction recovery, the benefits and risks of active ICD therapy, and surrogate measures that may have a role in risk stratification.
Collapse
|
5
|
Selvaraj RJ, Rangasamy S, Priya D, Nair S, Pillai AA, Satheesh S, Jayaraman B. Sudden death and its predictors in myocardial infarction survivors in an Indian population. Indian Pacing Electrophysiol J 2020; 21:82-87. [PMID: 33352202 PMCID: PMC7952752 DOI: 10.1016/j.ipej.2020.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/27/2020] [Accepted: 12/15/2020] [Indexed: 11/30/2022] Open
Abstract
Objective This study was conducted to assess the incidence of sudden cardiac death (SCD) in post myocardial infarction patients and to determine the predictive value of various risk markers in identifying cardiac mortality and SCD. Methods Left ventricular function, arrhythmias on Holter and microvolt T wave alternans (MTWA) were assessed in patients with prior myocardial infarction and ejection fraction ≤ 40%. The primary outcome was a composite of cardiac death and resuscitated cardiac arrest during follow up. Secondary outcomes included total mortality and SCD. Results Fifty-eight patients were included in the study. Eight patients (15.5%) died during a mean follow-up of 22.3 ± 6.6 months. Seven of them (12.1%) had SCD. Among the various risk markers studied, left ventricular ejection fraction (LVEF) ≤ 30% (Hazard ratio 5.6, 95% CI 1.39 to 23) and non-sustained ventricular tachycardia (NSVT) in holter (5.7, 95% CI 1.14 to 29) were significantly associated with the primary outcome in multivariate analysis. Other measures, including QRS width, heart rate variability, heart rate turbulence and MTWA showed no association. Conclusions Among patients with prior myocardial infarction and reduced left ventricular function, the rate of cardiac death was substantial, with most of these being sudden cardiac death. Both LVEF ≤30% and NSVT were associated with cardiac death whereas only LVEF predicted SCD. Other parameters did not appear useful for prediction of events in these patients. These findings have implications for decision making for the use of implantable cardioverter defibrillators for primary prevention in these patients.
Collapse
Affiliation(s)
- Raja J Selvaraj
- Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
| | - Sasinthar Rangasamy
- Department of Cardiology, Mahatma Gandhi Medical College and Research Institute, Pondicherry, India
| | - Dhivya Priya
- Department of Medical Biometrics and Informatics (Biostatistics), Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Sreekumaran Nair
- Department of Medical Biometrics and Informatics (Biostatistics), Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Ajith Ananthakrishna Pillai
- Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Santhosh Satheesh
- Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| | - Balachander Jayaraman
- Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India
| |
Collapse
|
6
|
Hsieh YC, Hsieh WH, Li CH, Liao YC, Lin JC, Weng CJ, Lo MT, Tuan TC, Lin SF, Yeh HI, Huang JL, Haugan K, Larsen BD, Lin YJ, Lin WW, Wu TJ, Chen SA. Ventricular divergence correlates with epicardial wavebreaks and predicts ventricular arrhythmia in isolated rabbit hearts during therapeutic hypothermia. PLoS One 2020; 15:e0228818. [PMID: 32084145 PMCID: PMC7034916 DOI: 10.1371/journal.pone.0228818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 01/23/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION High beat-to-beat morphological variation (divergence) on the ventricular electrogram during programmed ventricular stimulation (PVS) is associated with increased risk of ventricular fibrillation (VF), with unclear mechanisms. We hypothesized that ventricular divergence is associated with epicardial wavebreaks during PVS, and that it predicts VF occurrence. METHOD AND RESULTS Langendorff-perfused rabbit hearts (n = 10) underwent 30-min therapeutic hypothermia (TH, 30°C), followed by a 20-min treatment with rotigaptide (300 nM), a gap junction modifier. VF inducibility was tested using burst ventricular pacing at the shortest pacing cycle length achieving 1:1 ventricular capture. Pseudo-ECG (p-ECG) and epicardial activation maps were simultaneously recorded for divergence and wavebreaks analysis, respectively. A total of 112 optical and p-ECG recordings (62 at TH, 50 at TH treated with rotigaptide) were analyzed. Adding rotigaptide reduced ventricular divergence, from 0.13±0.10 at TH to 0.09±0.07 (p = 0.018). Similarly, rotigaptide reduced the number of epicardial wavebreaks, from 0.59±0.73 at TH to 0.30±0.49 (p = 0.036). VF inducibility decreased, from 48±31% at TH to 22±32% after rotigaptide infusion (p = 0.032). Linear regression models showed that ventricular divergence correlated with epicardial wavebreaks during TH (p<0.001). CONCLUSION Ventricular divergence correlated with, and might be predictive of epicardial wavebreaks during PVS at TH. Rotigaptide decreased both the ventricular divergence and epicardial wavebreaks, and reduced the probability of pacing-induced VF during TH.
Collapse
Affiliation(s)
- Yu-Cheng Hsieh
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Department of Data Science and Big Data Analytics and Department of Financial Engineering, Providence University, Taichung, Taiwan
- * E-mail:
| | - Wan-Hsin Hsieh
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
| | - Cheng-Hung Li
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Department of Data Science and Big Data Analytics and Department of Financial Engineering, Providence University, Taichung, Taiwan
| | - Ying-Chieh Liao
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Department of Data Science and Big Data Analytics and Department of Financial Engineering, Providence University, Taichung, Taiwan
| | - Jiunn-Cherng Lin
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Department of Data Science and Big Data Analytics and Department of Financial Engineering, Providence University, Taichung, Taiwan
| | - Chi-Jen Weng
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Department of Data Science and Big Data Analytics and Department of Financial Engineering, Providence University, Taichung, Taiwan
| | - Men-Tzung Lo
- Research Center for Adaptive Data Analysis, National Central University, Jhongli City, Taiwan
| | - Ta-Chuan Tuan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shien-Fong Lin
- Krannert Institute of Cardiology and the Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States of America
- Institute of Biomedical Engineering, National Chiao-Tung University, Hsinchu, Taiwan
| | - Hung-I Yeh
- Departments of Internal Medicine and Medical Research, Mackay Memorial Hospital, Mackay Medical College, New Taipei City, Taiwan
| | - Jin-Long Huang
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Ketil Haugan
- Department of Cardiology, Zealand University Hospital, Roskilde, Denmark
| | | | - Yenn-Jiang Lin
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wei-Wen Lin
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Life Science, Tunghai University, Taichung, Taiwan
| | - Tsu-Juey Wu
- Cardiovascular Center, Taichung Veterans General Hospital and Chiayi Branch, Taichung and Chiayi, Taiwan
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Shih-Ann Chen
- Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| |
Collapse
|
7
|
Pathak RK, Sanders P, Deo R. Primary prevention implantable cardioverter-defibrillator and opportunities for sudden cardiac death risk assessment in non-ischaemic cardiomyopathy. Eur Heart J 2019; 39:2859-2866. [PMID: 30020440 DOI: 10.1093/eurheartj/ehy344] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/25/2018] [Indexed: 01/28/2023] Open
Abstract
Sudden cardiac death (SCD) accounts for approximately one-third of all deaths among patients with non-ischaemic cardiomyopathy (NICM). Implantable cardioverter-defibrillator (ICD) therapy has been the primary intervention for managing individuals at high risk for SCD. However, individual ICD trials in the NICM population have failed to demonstrate a mortality benefit with prophylactic ICD implantation. Current guidelines recommend ICD implantation in NICM patients with symptomatic heart failure and a left ventricular ≤35% and are based on meta-analyses of multiple trials that span three decades and include the recent Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischaemic Heart Failure on Mortality (DANISH) trial. These pooled analyses report a significant reduction in all-cause mortality with ICD implantation compared with medical therapy alone. In addition, each of these trials has demonstrated consistently a reduction in the risk of SCD compared with medical therapy alone. As a result, a refined approach of risk stratification that selects patients at the highest risk for SCD may lead to a significant improvement in ICD efficacy. In this clinical review, we first discuss the evolution of clinical trials that have evaluated ICDs in the NICM population. We then highlight some key markers of arrhythmia risk that hold promise in personalizing risk stratification for SCD.
Collapse
Affiliation(s)
- Rajeev K Pathak
- Electrophysiology Section, Division of Cardiovascular Medicine, Perelman School of Medicine at the University of Pennsylvania, 9 Founders Pavilion, 3400 Spruce Street, Philadelphia, PA, USA
| | - Prashanthan Sanders
- Center for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, University of Adelaide and Royal Adelaide Hospital, North Terrace, Adelaide, Australia
| | - Rajat Deo
- Electrophysiology Section, Division of Cardiovascular Medicine, Perelman School of Medicine at the University of Pennsylvania, 9 Founders Pavilion, 3400 Spruce Street, Philadelphia, PA, USA
| |
Collapse
|
8
|
Microvolt T-wave alternans at the end of surgery is associated with postoperative mortality in cardiac surgery patients. Sci Rep 2019; 9:17351. [PMID: 31758018 PMCID: PMC6874567 DOI: 10.1038/s41598-019-53760-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/05/2019] [Indexed: 11/08/2022] Open
Abstract
Microvolt T-wave alternans (MTWA), which reflects electrical dispersion of repolarization, is known to be associated with arrhythmia or sudden cardiac death in high risk patients. In this study we investigated the relationship between MTWA and postoperative mortality in 330 cardiac surgery patients. Electrocardiogram, official national data and electric chart were analysed to provide in-hospital and mid-term outcome. MTWA at the end of surgery was significantly associated with in-hospital mortality in both univariate analysis (OR = 27.378, 95% CI 5.616-133.466, p < 0.001) and multivariate analysis (OR = 59.225, 95% CI 6.061-578.748, p < 0.001). Cox proportional hazards model revealed MTWA at the end of surgery was independently associated with mid-term mortality (HR = 4.337, 95% CI 1.594-11.795). The area under the curve of the model evaluating MTWA at the end of surgery was 0.764 (95% CI, 0.715-0.809) and it increased to 0.929 (95% CI, 0.896-0.954) when combined with the EuroSCORE II. MTWA positive at the end of surgery had a 60-fold increase in in-hospital mortality and a 4-fold increase in mid-term mortality. Moreover, MTWA at the end of surgery could predict in-hospital mortality and this predictability is more robust when combined with the EuroSCORE II.
Collapse
|
9
|
Xue SL, Hou XF, Sun KY, Wang Y, Qian ZY, Wang QP, Shen SP, Yin HL, Zhang R, Yin HP, Zou JG. Microvolt T-wave alternans complemented with electrophysiologic study for prediction of ventricular tachyarrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy: a long-term follow-up study. Chin Med J (Engl) 2019; 132:1406-1413. [PMID: 31205097 PMCID: PMC6629327 DOI: 10.1097/cm9.0000000000000239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The long-term predicted value of microvolt T-wave alternans (MTWA) for ventricular tachyarrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. Our study explored the characteristics of MTWA and its prognostic value when combined with an electrophysiologic study (EPS) in patients with ARVC. METHODS All patients underwent non-invasive MTWA examination with modified moving average (MMA) analysis and an EPS. A positive event was defined as the first occurrence of sudden cardiac death, documented sustained ventricular tachycardia (VT), ventricular fibrillation, or the administration of appropriate implantable cardioverter defibrillator therapy including shock or anti-tachycardia pacing. RESULTS Thirty-five patients with ARVC (age 38.6 ± 11.0 years; 28 males) with preserved left ventricular (LV) function were recruited. The maximal TWA value (MaxValt) was 17.0 (11.0-27.0) μV. Sustained VT was induced in 22 patients by the EPS. During a median follow-up of 99.9 ± 7.7 months, 15 patients had positive clinical events. When inducible VT was combined with the MaxValt, the area under the curve improved from 0.739 to 0.797. The receiver operating characteristic curve showed that a MaxValt of 23.5 μV was the optimal cutoff value to identify positive events. The multivariate Cox regression model for survival showed that MTWA (MaxValt, hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.01-1.11; P = 0.01) and inducible VT (HR, 5.98; 95% CI, 1.33-26.8; P = 0.01) independently predicted positive events in patients with ARVC. CONCLUSIONS MTWA assessment with MMA analysis complemented by an EPS might provide improved prognostic ability in patients with ARVC with preserved LV function during long-term follow-up.
Collapse
Affiliation(s)
- She-Liang Xue
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
- Department of Cardiology, The Affiliated Wujin Hospital of Jiangsu University, Changzhou, Jiangsu 213002, China
| | - Xiao-Feng Hou
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Kang-Yun Sun
- Department of Cardiology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu 215008, China
| | - Yao Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Zhi-Yong Qian
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Quan-Peng Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Si-Peng Shen
- Department of Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Hong-Li Yin
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Rong Zhang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Hai-Ping Yin
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Jian-Gang Zou
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
- Key Laboratory of Targeted Intervention in Cardiovascular Disease, Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| |
Collapse
|
10
|
Hasan MA, Abbott D, Baumert M, Krishnan S. Increased beat-to-beat T-wave variability in myocardial infarction patients. ACTA ACUST UNITED AC 2018; 63:123-130. [PMID: 28002025 DOI: 10.1515/bmt-2015-0186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/15/2016] [Indexed: 11/15/2022]
Abstract
The purpose of this study was to investigate the beat-to-beat variability of T-waves (TWV) and to assess the diagnostic capabilities of T-wave-based features for myocardial infarction (MI). A total of 148 recordings of standard 12-lead electrocardiograms (ECGs) from 79 MI patients (22 females, mean age 63±12 years; 57 males, mean age 57±10 years) and 69 recordings from healthy subjects (HS) (17 females, 42±18 years; 52 males, 40±13 years) were studied. For the quantification of beat-to-beat QT intervals in ECG signal, a template-matching algorithm was applied. To study the T-waves beat-to-beat, we measured the angle between T-wave max and T-wave end with respect to Q-wave (∠α) and T-wave amplitudes. We computed the standard deviation (SD) of beat-to-beat T-wave features and QT intervals as markers of variability in T-waves and QT intervals, respectively, for both patients and HS. Moreover, we investigated the differences in the studied features based on gender and age for both groups. Significantly increased TWV and QT interval variability (QTV) were found in MI patients compared to HS (p<0.05). No significant differences were observed based on gender or age. TWV may have some diagnostic attributes that may facilitate identifying patients with MI. In addition, the proposed beat-to-beat angle variability was found to be independent of heart rate variations. Moreover, the proposed feature seems to have higher sensitivity than previously reported feature (QT interval and T-wave amplitude) variability for identifying patients with MI.
Collapse
Affiliation(s)
- Muhammad A Hasan
- Department of Electrical and Computer Engineering, Ryerson University, Toronto, Canada
- Department of Electrical and Electronics Engineering, The University of Adelaide, Adelaide, Australia
| | - Derek Abbott
- Department of Electrical and Electronics Engineering, The University of Adelaide, Adelaide, Australia
| | - Mathias Baumert
- Department of Electrical and Electronics Engineering, The University of Adelaide, Adelaide, Australia
| | - Sridhar Krishnan
- Department of Electrical and Computer Engineering, Ryerson University, Toronto, Canada
| |
Collapse
|
11
|
Non-sustained microvolt level T-wave alternans in congenital long QT syndrome types 1 and 2. J Electrocardiol 2017; 51:303-308. [PMID: 29183619 DOI: 10.1016/j.jelectrocard.2017.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND Patients with long QT syndrome (LQTS) are predisposed to polymorphic ventricular tachycardia (VT) during adrenergic stimulation. Microvolt T-wave alternans (MTWA) is linked to vulnerability to VT in structural heart disease. The prevalence of non-sustained MTWA (NS-MTWA) in LQTS is unknown. METHODS 31 LQT1, 42 LQT2, and 80 controls underwent MTWA testing during exercise. MTWA tests were classified per standardized criteria, and re-analyzed according to the modified criteria to account for NS-MTWA. RESULTS LQT1 and LQT2 patients had a significantly higher frequency of late NS-MTWA (26% and 12%) compared to controls (0%). There was no significant difference between the groups with respect to sustained and early NS-MTWA. Late NS-MTWA was significantly associated with QTc. CONCLUSION LQT1 and LQT2 patients had a higher prevalence of late NS-MTWA during exercise than matched controls. NS-MTWA likely reflects transient adrenergically mediated dispersion of repolarization, and could be a marker of arrhythmic risk in LQTS.
Collapse
|
12
|
|
13
|
Pezawas T, Diedrich A, Robertson D, Winker R, Richter B, Wang L, Schmidinger H. Risk of arrhythmic death in ischemic heart disease: a prospective, controlled, observer-blind risk stratification over 10 years. Eur J Clin Invest 2017; 47:231-240. [PMID: 28102901 PMCID: PMC5392777 DOI: 10.1111/eci.12729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 01/16/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND Risk of arrhythmic death is considered highest in ischemic heart disease with severe left ventricular ejection fraction (LVEF) reduction. Non-invasive testing should improve decision-making of prophylactic defibrillator (ICD) implantation. DESIGN We enrolled 120 patients with ischemic heart disease and LVEF < 50% and 30 control subjects without ischemic heart disease and normal LVEF. An initial assessment, a second assessment after 3 years and a final follow-up comprised of pharmacological baroreflex testing (BRS), short-term spectral [low-frequency (LF) to high-frequency (HF) ratio] and long-term time-domain analysis of heart rate variability (SDNN), exercise Microvolt T-wave alternans (MTWA) and others. RESULTS The median follow-up was 7·5 years. Resuscitated cardiac arrest and arrhythmic death due to ventricular arrhythmias ≥ 240/min was observed in 18% and 15% of patients, respectively. Cardiac death was observed in 28% of patients. The incidence of arrhythmic death and resuscitated cardiac arrest was identical in patients with ischemic heart disease with LVEF < 30% and ≥ 30%. No significant difference between subgroups with LVEF of < 30%, 30-39% and ≥ 40% was found either. MTWA, BRS, SDNN and LF to HF ratio failed to identify patients at risk of arrhythmic death in a multiple regression model. CONCLUSIONS Ischemic heart disease patients with LVEF < 30% and ≥ 30% face the same risk of arrhythmic death. Stratification techniques fail to identify high-risk patients. Therefore, the current practice to constrain prophylactic ICDs to patients with severely reduced LVEF seems to be insufficient.
Collapse
Affiliation(s)
- Thomas Pezawas
- Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria
| | - André Diedrich
- Departments of Medicine, Clinical Pharmacology, Pharmacology, and Neurology, Vanderbilt Autonomic Dysfunction Center, Nashville, TN, USA
| | - David Robertson
- Departments of Medicine, Clinical Pharmacology, Pharmacology, and Neurology, Vanderbilt Autonomic Dysfunction Center, Nashville, TN, USA
| | | | - Bernhard Richter
- Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria
| | - Li Wang
- Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Herwig Schmidinger
- Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
14
|
Zhen Z, Chen Y, Liu JH, Chan CWS, Yuen M, Lam KSL, Tse HF, Yiu KH. Increased T-wave alternans is associated with subclinical myocardial structural and functional abnormalities in patients with type 2 diabetes. J Cardiol 2016; 68:329-34. [DOI: 10.1016/j.jjcc.2015.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/09/2015] [Accepted: 10/13/2015] [Indexed: 10/22/2022]
|
15
|
Ramanan T, Balakumaran K, Ravichandran S, Ganocy SJ, Oshodi G, Costantini O, Dettmer M, Leo PJ, Kaufman ES. Does manual T-wave window adjustment affect microvolt T-wave alternans results in patients with structural heart disease? J Electrocardiol 2016; 49:967-972. [PMID: 27597389 DOI: 10.1016/j.jelectrocard.2016.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Microvolt T-wave alternans (MTWA) analysis can identify patients at low risk of sudden cardiac death who might not benefit from an implantable cardioverter-defibrillator (ICD). Current spectral methodology for performing MTWA analysis may "miss" part of the T-wave in patients with QT prolongation. The value of T-wave window adjustment in patients with structural heart disease has not been studied. METHODS We assembled MTWA data from 5 prior prospective studies including 170 patients with reduced left ventricular ejection fraction, adjusted the T-wave window to include the entire T-wave, and reanalyzed MTWA. RESULTS Of 170 patients, 43% required T-wave window adjustment. Only 3 of 170 patients (1.8%) had a clinically significant change in MTWA results. CONCLUSIONS In 98.2% of patients, T-wave window adjustment did not improve the accuracy of MTWA analysis. Spectral MTWA as currently implemented remains effective for identifying patients with structural heart disease unlikely to benefit from ICD therapy.
Collapse
Affiliation(s)
- Tharmathai Ramanan
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Kathir Balakumaran
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Sairekha Ravichandran
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Stephen J Ganocy
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Ganiyu Oshodi
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Otto Costantini
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Mary Dettmer
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Peter J Leo
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA
| | - Elizabeth S Kaufman
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA.
| |
Collapse
|
16
|
Burattini L, Man S, Fioretti S, Di Nardo F, Swenne CA. Heart Rate-Dependent Hysteresis of T-Wave Alternans in Primary Prevention ICD Patients. Ann Noninvasive Electrocardiol 2015; 21:460-9. [PMID: 26671620 DOI: 10.1111/anec.12330] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND T-wave alternans (TWA) is usually performed at accelerated heart rates (HR) during exercise, while recovery TWA is typically not analyzed. Consequently, it is still unknown if TWA shows a HR-dependent hysteresis or not. Thus, the aim of the present study was to investigate TWA dependency on HR during both the exercise and recovery phases of an ergometer test, and to evaluate if recovery TWA may contribute to identify subjects at increased risk of arrhythmic events. METHODS Our HR adaptive match filter was used to identify TWA from electrocardiographic recordings acquired during a bicycle ergometer test in 266 patients with implanted cardio-defibrillator. During the 4-year follow-up, 76 patients developed tachycardia or ventricular fibrillation (ICD_Cases) and 190 did not (ICD_Controls). RESULTS TWA was statistically lower during exercise than recovery for HRs between 75 and 110 bpm (16-21 μV vs 20-27 μV; P < 0.05), and reverse for HRs between 120 and 130 bpm (41-51 μV vs 28 μV; P < 0.05). ICD_Cases and ICD_Controls showed significantly different TWA at 80 bpm (20 μV vs 15 μV; P < 0.05) and 140 bpm (15 μV vs 22 μV; P < 0.05) during exercise, and at 90 bpm (38 μV vs 21 μV; P < 0.05) and 95 bpm (33-24 μV vs 28 μV; P < 0.05) during recovery. CONCLUSIONS TWA shows a HR-dependent hysteresis and there is a different behavior of TWA in ICD_Cases and ICD_Controls groups. Consequently, beside exercise TWA also recovery TWA may contribute to identify subjects at increased risk of arrhythmic events.
Collapse
Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Sumche Man
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Sandro Fioretti
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Francesco Di Nardo
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Cees A Swenne
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
17
|
Perkiömäki J, Exner DV, Piira OP, Kavanagh K, Lepojärvi S, Talajic M, Karvonen J, Philippon F, Junttila J, Coutu B, Huikuri H. Heart Rate Turbulence and T-Wave Alternans in Patients with Coronary Artery Disease: The Influence of Diabetes. Ann Noninvasive Electrocardiol 2015; 20:481-7. [PMID: 25589197 DOI: 10.1111/anec.12244] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Patients with diabetes mellitus (DM) have a higher risk of sudden cardiac death. Factors associated with the risk profiles of coronary artery disease (CAD) patients with DM are not well established. Heart rate turbulence (HRT) and T-wave alternans (TWA) are often used to predict arrhythmia events. METHODS AND RESULTS HRT and TWA were measured in two independent groups: the ARTEMIS cohort study and the REFINE-ICD randomized trial. ARTEMIS assesses risk 3-12 months after coronary angiography in patients with CAD. The initial 1001 patients in ARTEMIS, 526 with and 475 without DM, are included in this analysis. REFINE-ICD compares usual care versus usual care plus ICD therapy in patients with left ventricular (LV) ejection fraction (EF) values of 36-50% assessed 2-15 months after myocardial infarction. The initial 275 patients screened in REFINE ICD are included in this analysis. Abnormal HRT plus TWA was more common in patients with versus without DM in ARTEMIS (125/526, 24% vs 63/475, 13%; P < 0.001) and REFINE-ICD (43/55, 78% vs 55/220, 25%; P < 0.001), respectively. Abnormal HRT plus TWA was also more common in patients with LVEF values < 50% (28%) vs ≥ 50% (18%; P < 0.001) in ARTEMIS and LVEF values below the population median of 42% (60/138, 43%) versus above the median (38/137, 28%; P < 0.01) in REFINE-ICD. CONCLUSIONS Abnormal HRT plus TWA is more common in CAD patients with DM compared with the patients without DM and is related to the severity of LV dysfunction. CLINICAL TRIAL REGISTRATION INFORMATION http://www.clinicaltrials.gov, NCT01426685; http://www.clinicaltrials.gov, NCT00673842.
Collapse
Affiliation(s)
- Juha Perkiömäki
- Division of Cardiology, Institute of Clinical Medicine, University of Oulu, and University Hospital of Oulu, Finland
| | - Derek V Exner
- Libin Cardiovascular Institute of Alberta, Calgary, Alberta, Canada
| | - Olli-Pekka Piira
- Division of Cardiology, Institute of Clinical Medicine, University of Oulu, and University Hospital of Oulu, Finland
| | | | - Samuli Lepojärvi
- Division of Cardiology, Institute of Clinical Medicine, University of Oulu, and University Hospital of Oulu, Finland
| | - Mario Talajic
- Cardiology, Montreal Heart Institute, Montreal, Quebec, Canada
| | - Jarkko Karvonen
- Division of Cardiology, Institute of Clinical Medicine, University of Oulu, and University Hospital of Oulu, Finland
| | | | - Juhani Junttila
- Division of Cardiology, Institute of Clinical Medicine, University of Oulu, and University Hospital of Oulu, Finland
| | - Benoit Coutu
- Centre Hopital University of Montreal, Montreal, Quebec, Canada
| | - Heikki Huikuri
- Division of Cardiology, Institute of Clinical Medicine, University of Oulu, and University Hospital of Oulu, Finland
| |
Collapse
|
18
|
Burattini L, Man S, Fioretti S, Di Nardo F, Swenne CA. Dependency of exercise-induced T-wave alternans predictive power for the occurrence of ventricular arrhythmias from heart rate. Ann Noninvasive Electrocardiol 2014; 20:345-54. [PMID: 25367434 DOI: 10.1111/anec.12224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND T-wave alternans (TWA) is a noninvasive index of risk for the occurrence of ventricular arrhythmias. It is known that TWA amplitude (TWAA) increases with heart rate (HR) but how the TWA predictive power varies with HR remains unknown. Thus, the aim of this study was to evaluate the dependency of exercise-induced TWA predictive power for the occurrence of ventricular arrhythmias from HR. METHODS TWA was identified using our HR adaptive match filter in exercise ECGs from 248 patients with implanted cardiac defibrillator (ICD), of which 72 developed ventricular tachycardia and/or fibrillation during the 4 year follow-up (ICD_Cases) and 176 did not (ICD_Controls). TWA predictive power was evaluated at HRs from 80 to 120 bpm by computing the area under the receiver operating characteristic curve (AUC) obtained using the maximum TWAA (maxTWAA) and the TWAA ratio (TWAAratio; i.e., the ratio between TWAA at a specific HR and at 80 bpm). RESULTS TWAA increased with HR. At 80 bpm maxTWAA was lower than at 120 bpm in both ICD_Cases (22 μV vs 41 μV; P < 10(-2) ) and ICD_ Controls (16 μV vs 36 μV; P < 10(-4) ). However, only at 80 bpm ICD_Cases showed significantly higher maxTWAA than ICD_Controls (AUC = 0.6486; P = 0.0080). TWAAratio was higher in ICD_Controls than ICD_Cases for all HR but 120 bpm, and its predictive power was maximum at 115 bpm (AUC = 0.6914; P < 0.05). CONCLUSIONS Exercise-induced TWA predictive power for the occurrence of ventricular arrhythmias, quantified using both maxTWAA and TWAAratio, was higher at low rather than at high HR.
Collapse
Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy.,B.M.E.D. Bio-Medical Engineering Development SRL, Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Sumche Man
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Francesco Di Nardo
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| | - Cees A Swenne
- B.M.E.D. Bio-Medical Engineering Development SRL, Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy
| |
Collapse
|
19
|
Surgit O, Erturk M, Buturak A, Akgul O, Pusuroglu H, Cakmak HA, Yazan S, Gul M, Akkaya E, Eksik A. The assessment of relationship between left ventricular geometry and microvolt T-wave alternans in sustained hypertension. Blood Press 2014; 23:349-55. [PMID: 24919782 DOI: 10.3109/08037051.2014.923252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Left ventricular (LV) hypertrophy (LVH) predicts increased mortality in part due to an elevated incidence of sudden cardiac death in hypertension. The aim of the present study was to investigate the relation of microvolt T-wave alternans (MTWA) with different LV geometric patterns in patient with sustained hypertension. METHODS This study consisted of 311 consecutive patients with sustained hypertension who were divided into four groups according to LV geometrical patterns. 90 patients were in the normal geometry group (NGG) [mean age 49.6 ± 7.8 years; 60 males (66.7%)], 99 patients were in the concentric remodeling group (CRG) [mean age 50.9 ± 6.6 years; 50 males (50.6%)], 63 patients were in the concentric hypertrophy group (CHG) [mean age 51.6 ± 7.3 years; 32 males (50.7%)] and 58 patients were in the eccentric hypertrophy group (EHG) [mean age 51.6 ± 9.0 years; 30 males (51.7%)]. Physical examination, laboratory work-up, office blood pressure measurement, transthoracic echocardiography and MTWA measurements were performed on all participants. RESULTS MTWA positivity was significantly higher in EHG and CHG as compared to CRG and NGG (p < 0.001). Left ventricle mass index (LVMI), LV end-diastolic diameter (LVEDD), LV end-systolic diameter (LVESD), interventricular septum diameter (IVSd), posterior wall diameter (PWd) and office systolic blood pressure (SBP) were found to be significantly positively correlated with MTWA (all p-values < 0.05). CONCLUSION We demonstrated that increased LVMI is associated with an elevated MTWA positivity in sustained hypertensives. Moreover, clinically significant LV geometric patterns including both concentric and eccentric hypertrophy are related with a raised MTWA positivity, which may lead to particular predilection to life-threatening ventricular arrhythmias and sudden cardiac death in sustained hypertension.
Collapse
Affiliation(s)
- Ozgur Surgit
- Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital, Department of Cardiology , Istanbul , Turkey
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Anné W, Theuns DAMJ, Schaer B, Van Belle Y, Szili-Torok T, Smith T, Res J, Jordaens L. ICDs at higher age and clinical risk factors. Neth Heart J 2014; 22:279-85. [PMID: 24795210 PMCID: PMC4031358 DOI: 10.1007/s12471-014-0553-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The implantable cardioverter defibrillator (ICD) is effective in preventing sudden cardiac death. However, in elderly patients (aged 75 years or older) the role of ICDs is still not well-defined and controversial. METHODS We retrospectively analysed all clinical and survival data of all ICD patients who were ≥75 years at the date of implantation in the Erasmus MC, Rotterdam, the Netherlands and the University Hospital, Basel, Switzerland. Kaplan-Meier survival analysis was performed, and mortality predictors were identified. Mortality of the cohort was compared with a random sample of patients aged 60-70 years originating from the same database and to an age- and sex-matched cohort of Dutch persons. RESULTS The study cohort consisted of 179 patients aged 75 years or older who were implanted between February 1999 and July 2008. The median follow-up time was 2.0 (IQR 2.8) years. Survival rates after 1, 2 and 3 years were 87, 82, 75 %, respectively. Survival was similar for primary and secondary prevention. Mortality in this study population could be predicted by combining four clinical risk factors: QRS duration >120 ms, NYHA class > II, renal failure and atrial fibrillation (AF). Survival was worse compared with the group of ICD patients aged 60-70 years and to the age- and sex-matched group of elderly persons. However, survival was not significantly worse when comparing elderly ICD patients without additional risk factors to the general population. CONCLUSIONS Elderly patients still have an acceptable survival probability independent of prevention indication, certainly if there are no additional clinical risk factors. The presence or absence of additional clinical risk factors should be taken into account when making the decision for implantation, since they strongly correlate with survival.
Collapse
Affiliation(s)
- W Anné
- Department of Cardiology, Thoraxcenter-Ba 581, Erasmus MC, 's Gravendijkwal 230, 3015-CE, Rotterdam, the Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Ragupathi L, Pavri BB. Tools for risk stratification of sudden cardiac death: a review of the literature in different patient populations. Indian Heart J 2014; 66 Suppl 1:S71-81. [PMID: 24568833 DOI: 10.1016/j.ihj.2013.12.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 12/14/2022] Open
Abstract
While various modalities to determine risk of sudden cardiac death (SCD) have been reported in clinical studies, currently reduced left ventricular ejection fraction remains the cornerstone of SCD risk stratification. However, the absolute burden of SCD is greatest amongst populations without known cardiac disease. In this review, we summarize the evidence behind current guidelines for implantable cardioverter defibrillator (ICD) use for the prevention of SCD in patients with ischemic heart disease (IHD). We also evaluate the evidence for risk stratification tools beyond clinical guidelines in the general population, patients with IHD, and patients with other known or suspected medical conditions.
Collapse
Affiliation(s)
| | - Behzad B Pavri
- Thomas Jefferson University Hospital, Philadelphia, PA, USA.
| |
Collapse
|
22
|
Yap SC, Harris L. Sudden cardiac death in adults with congenital heart disease. Expert Rev Cardiovasc Ther 2014; 7:1605-20. [DOI: 10.1586/erc.09.153] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
23
|
TEN SANDE JUDITHN, DAMMAN PETER, TIJSSEN JANG, DE GROOT JORISR, KNOPS REINOUDE, WILDE ARTHURA, VAN DESSEL PASCALF. Value of Serial Heart Rate Variability Measurement for Prediction of Appropriate ICD Discharge in Patients with Heart Failure. J Cardiovasc Electrophysiol 2013; 25:60-5. [DOI: 10.1111/jce.12280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/14/2013] [Accepted: 08/21/2013] [Indexed: 12/12/2022]
Affiliation(s)
- JUDITH N. TEN SANDE
- Department of Cardiology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - PETER DAMMAN
- Department of Cardiology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - JAN G.P. TIJSSEN
- Department of Cardiology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - JORIS R. DE GROOT
- Department of Cardiology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - REINOUD E. KNOPS
- Department of Cardiology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - ARTHUR A.M. WILDE
- Department of Cardiology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| | - PASCAL F.H.M. VAN DESSEL
- Department of Cardiology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
| |
Collapse
|
24
|
A combined anatomic and electrophysiologic substrate based approach for sudden cardiac death risk stratification. Am Heart J 2013; 166:744-52. [PMID: 24093856 DOI: 10.1016/j.ahj.2013.06.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 06/30/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND Although left ventricular ejection fraction (LVEF) is the primary determinant for sudden cardiac death (SCD) risk stratification, in isolation, LVEF is a sub-optimal risk stratifier. We assessed whether a multi-marker strategy would provide more robust SCD risk stratification than LVEF alone. METHODS We collected patient-level data (n = 3355) from 6 studies assessing the prognostic utility of microvolt T-wave alternans (MTWA) testing. Two thirds of the group was used for derivation (n = 2242) and one-third for validation (n = 1113). The discriminative capacity of the multivariable model was assessed using the area under the receiver-operating characteristic curve (c-index). The primary endpoint was SCD at 24 months. RESULTS In the derivation cohort, 59 patients experienced SCD by 24 months. Stepwise selection suggested that a model based on 3 parameters (LVEF, coronary artery disease and MTWA status) provided optimal SCD risk prediction. In the derivation cohort, the c-index of the model was 0.817, which was significantly better than LVEF used as a single variable (0.637, P < .001). In the validation cohort, 36 patients experienced SCD by 24 months. The c-index of the model for predicting the primary endpoint was again significantly better than LVEF alone (0.774 vs 0.671, P = .020). CONCLUSIONS A multivariable model based on presence of coronary artery disease, LVEF and MTWA status provides significantly more robust SCD risk prediction than LVEF as a single risk marker. These findings suggest that multi-marker strategies based on different aspects of the electro-anatomic substrate may be capable of improving primary prevention implantable cardioverter-defibrillator treatment algorithms.
Collapse
|
25
|
Burattini L, Man S, Sweene CA. The power of exercise-induced T-wave alternans to predict ventricular arrhythmias in patients with implanted cardiac defibrillator. JOURNAL OF HEALTHCARE ENGINEERING 2013; 4:167-84. [PMID: 23778010 DOI: 10.1260/2040-2295.4.2.167] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The power of exercise-induced T-wave alternans (TWA) to predict the occurrence of ventricular arrhythmias was evaluated in 67 patients with an implanted cardiac defibrillator (ICD). During the 4-year follow-up, electrocardiographic (ECG) tracings were recorded in a bicycle ergometer test with increasing workload ranging from zero (NoWL) to the patient's maximal capacity (MaxWL). After the follow-up, patients were classified as either ICD_Cases (n = 29), if developed ventricular tachycardia/fibrillation, or ICD_Controls (n = 38). TWA was quantified using our heart-rate adaptive match filter. Compared to NoWL, MaxWL was characterized by faster heart rates and higher TWA in both ICD_Cases (12-18 μ V vs. 20-39 μ V; P < 0.05) and ICD_Controls (9-15 μ V vs. 20-32 μ V; P < 0.05). Still, TWA was able to discriminate the two ICD groups during NoWL (sensitivity = 59-83%, specificity = 53-84%) but not MaxWL (sensitivity = 55-69%, specificity = 39-74%). Thus, this retrospective observational case-control study suggests that TWA's predictive power for the occurrence of ventricular arrhythmias could increase at low heart rates.
Collapse
Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy.
| | | | | |
Collapse
|
26
|
A unified procedure for detecting, quantifying, and validating electrocardiogram T-wave alternans. Med Biol Eng Comput 2013; 51:1031-42. [DOI: 10.1007/s11517-013-1084-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 05/11/2013] [Indexed: 10/26/2022]
|
27
|
Dagres N, Hindricks G. Risk stratification after myocardial infarction: is left ventricular ejection fraction enough to prevent sudden cardiac death? Eur Heart J 2013; 34:1964-71. [PMID: 23644180 DOI: 10.1093/eurheartj/eht109] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Patients who have experienced a myocardial infarction (MI) are at increased risk of sudden cardiac death (SCD). With the advent of implantable cardioverter-defibrillators (ICDs), accurate risk stratification has become very relevant. Numerous investigations have proven that a reduced left ventricular ejection fraction (LVEF) significantly increases the SCD risk. Furthermore, ICD implantation in patients with reduced LVEF confers significant survival benefit. As a result, LVEF is the cornerstone of current decision making for prophylactic ICD implantation after MI. However, LVEF as standalone risk stratifier has major limitations: (i) the majority of SCD cases occur in patients with preserved or moderately reduced LVEF, (ii) only relatively few patients with reduced LVEF will benefit from an ICD (most will never experience a threatening arrhythmic event, others have a high risk for non-sudden death), (iii) a reduced LVEF is a risk factor for both sudden and non-sudden death. Several other non-invasive and invasive risk stratifiers, such as ventricular ectopy, QRS duration, signal-averaged electrocardiogram, microvolt T-wave alternans, markers of autonomic tone as well as programmed ventricular stimulation, have been evaluated. However, none of these techniques has unequivocally demonstrated the efficacy when applied alone or in combination with LVEF. Apart from their limited sensitivity, most of them are risk factors for both sudden and non-sudden death. Considering the multiple mechanisms involved in SCD, it seems unlikely that a single test will prove adequate for all patients. A combination of clinical characteristics with selected stratification tools may significantly improve risk stratification in the future.
Collapse
Affiliation(s)
- Nikolaos Dagres
- Second Department of Cardiology, University of Athens, Attikon University Hospital, Athens, Greece
| | | |
Collapse
|
28
|
Microvolt T-wave alternans predicts cardiac events after acute myocardial infarction in patients treated with primary percutaneous coronary intervention. Adv Med Sci 2012. [PMID: 23183770 DOI: 10.2478/v10039-012-0033-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Current risk stratification after acute myocardial infarction (MI) depends on left ventricular ejection fraction. Microvolt T-wave alternans (MTWA) is one of promising markers to predict cardiac events in patients after acute MI treated according to current guidelines. METHODS In this single center study, 112 consecutive patients with the first anterior ST-elevation MI undergoing PCI <12 hours from symptom onset, were enrolled prospectively. Demographics, established risk factors, myocardial contrast echocardiography (MCE) perfusion, index event data and MTWA were assessed. Composite cardiac events (CCE) defined as: death, recurrent MI, sustained ventricular tachycardia (sVT) or readmission for acute heart failure (HF) were recorded during follow-up. RESULTS MTWA test was negative in 76, positive in 18 and undetermined in 7 patients. MTWA negative patients had significantly higher LVEF at 30 days. At 4 years, 26 patients experienced CCE (10 died, 2 reinfarcted and 14 HF events). In multivariate Cox proportional hazard model maximum CKMB, non-negative MTWA and reduced LVEF made the best model to predict CCE. Four year CCE free survival was 77% and was significantly lower for non-negative MTWA (94% vs 50%, p<0.003). CONCLUSIONS Non-negative MTWA with infarct size index and reduced LVEF could predict cardiac events in patients with anterior STEMI treated with primary PCI. MTWA non-negative patients have significantly worse outcome.
Collapse
|
29
|
Gatzoulis KA, Tsiachris D, Dilaveris P, Archontakis S, Arsenos P, Vouliotis A, Sideris S, Trantalis G, Kartsagoulis E, Kallikazaros I, Stefanadis C. Implantable cardioverter defibrillator therapy activation for high risk patients with relatively well preserved left ventricular ejection fraction. Does it really work? Int J Cardiol 2012; 167:1360-5. [PMID: 22534047 DOI: 10.1016/j.ijcard.2012.04.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 12/29/2011] [Accepted: 04/01/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND Current guidelines for the primary prevention of sudden cardiac death have used a left ventricular ejection fraction (LVEF) ≤ 35% as a critical point to justify implantable cardioverter defibrillator (ICD) implantation in post myocardial infarction patients and in those with nonischemic dilated cardiomyopathy. We compared mortality and ICD activation rates among different ICD group recipients using a cut-off value for LVEF ≤ 35%. METHODS We followed up for a mean period of 41.1 months 495 ICD recipients (442 males, 65.6 years old, 68.9% post myocardial infarction patients, 422 with LVEF ≤ 35%). Prevention was considered primary in patients who fulfilled guidelines criteria or had inducible ventricular arrhythmia during programmed ventricular stimulation for patients with LVEF >35%. RESULTS Over the course of the trial, 84 of 495 patients died; 69 experienced cardiac death (6 sudden) and 15 non cardiac death. ICD recipients with LVEF ≤ 35% compared to those with preserved LVEF (mean LVEF=43%) had a greater incidence of total mortality (18% vs. 11%, log rank p=0.028) and cardiac death (15.4% vs. 5.5%, log rank p=0.005). There was no difference in the incidence for appropriate device therapy between patients with LVEF ≤ 35% and those with LVEF >35% (56.9% vs. 65.8%, log rank p=0.93). In the multivariate analysis the presence of advanced New York Heart Association stage predicted both total mortality (HR=2.69, 95% CI 1.771-4.086) and cardiac death (HR=3.437, 95% CI 2.163-5.463). CONCLUSIONS ICD therapy may protect heart failure patients at early stages from arrhythmic morbidity and mortality, based on an electrophysiology-guided risk stratification approach.
Collapse
Affiliation(s)
- Konstantinos A Gatzoulis
- First Cardiology Department, University of Athens Medical School, Hippokration Hospital, Athens, Greece.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Iravanian S, Kanu UB, Christini DJ. A class of Monte-Carlo-based statistical algorithms for efficient detection of repolarization alternans. IEEE Trans Biomed Eng 2012; 59:1882-91. [PMID: 22481808 DOI: 10.1109/tbme.2012.2192733] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cardiac repolarization alternans is an electrophysiologic condition identified by a beat-to-beat fluctuation in action potential waveform. It has been mechanistically linked to instances of T-wave alternans, a clinically defined ECG alternation in T-wave morphology, and associated with the onset of cardiac reentry and sudden cardiac death. Many alternans detection algorithms have been proposed in the past, but the majority have been designed specifically for use with T-wave alternans. Action potential duration (APD) signals obtained from experiments (especially those derived from optical mapping) possess unique characteristics, which requires the development and use of a more appropriate alternans detection method. In this paper, we present a new class of algorithms, based on the Monte Carlo method, for the detection and quantitative measurement of alternans. Specifically, we derive a set of algorithms (one an analytical and more efficient version of the other) and compare its performance with the standard spectral method and the generalized likelihood ratio test algorithm using synthetic APD sequences and optical mapping data obtained from an alternans control experiment. We demonstrate the benefits of the new algorithm in the presence of Gaussian and Laplacian noise and frame-shift errors. The proposed algorithms are well suited for experimental applications, and furthermore, have low complexity and are implementable using fixed-point arithmetic, enabling potential use with implantable cardiac devices.
Collapse
Affiliation(s)
- Shahriar Iravanian
- Division of Cardiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | | | | |
Collapse
|
31
|
Clinical utility of microvolt T-wave alternans testing in identifying patients at high or low risk of sudden cardiac death. Heart Rhythm 2012; 9:1256-64.e2. [PMID: 22406384 DOI: 10.1016/j.hrthm.2012.03.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND Previous studies have demonstrated that microvolt T-wave alternans (MTWA) testing is a robust predictor of ventricular tachyarrhythmias and sudden cardiac death (SCD) in at-risk patients. However, recent studies have suggested that MTWA testing is not as good a predictor of "appropriate" implantable cardioverter-defibrillator (ICD) therapy as it is a predictor of SCD in patients without ICDs. OBJECTIVE To evaluate the utility of MTWA testing for SCD risk stratification in patients without ICDs. METHODS Patient-level data were obtained from 5 prospective studies of MTWA testing in patients with no history of ventricular arrhythmia or SCD. In these studies, ICDs were implanted in only a minority of patients and patients with ICDs were excluded from the analysis. We conducted a pooled analysis and examined the 2-year risk for SCD based on the MTWA test result. RESULTS The pooled cohort included 2883 patients. MTWA testing was positive in 856 (30%), negative in 1627 (56%), and indeterminate in 400 (14%) patients. Among patients with a left ventricular ejection fraction (LVEF) of ≤35%, annual SCD event rates were 4.0%, 0.9%, and 4.6% among groups with MTWA positive, negative, and indeterminate test results. The SCD rate was significantly lower among patients with a negative MTWA test result than in patients with either positive or indeterminate MTWA test results (P <.001 for both comparisons). In patients with an LVEF of >35%, annual SCD event rates were 3.0%, 0.3%, and 0.3% among the groups with MTWA positive, negative, and indeterminate test results. The SCD rate associated with a positive MTWA test result was significantly higher than that associated with either negative (P <.001) or indeterminate MTWA test results (P = .003). CONCLUSIONS In patients without ICDs, MTWA testing is a powerful predictor of SCD. Among patients with an LVEF of ≤35%, a negative MTWA test result is associated with a low risk for SCD. Conversely, among patients with an LVEF of >35%, a positive MTWA test result identifies patients at significantly heightened SCD risk. These findings may have important implications for refining primary prevention ICD treatment algorithms.
Collapse
|
32
|
Jackson CE, Myles RC, Tsorlalis IK, Dalzell JR, Spooner RJ, Rodgers JR, Bezlyak V, Greenlaw N, Ford I, Cobbe SM, Petrie MC, McMurray JJV. Profile of microvolt T-wave alternans testing in 1003 patients hospitalized with heart failure. Eur J Heart Fail 2012; 14:377-86. [PMID: 22334727 DOI: 10.1093/eurjhf/hfs010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Observational studies in selected populations have suggested that microvolt T-wave alternans (MTWA) testing may identify patients with heart failure (HF) at risk of sudden cardiac death. The aims of this study were to investigate the utility of MTWA testing in an unselected population of patients with HF and to evaluate the clinical characteristics associated with the MTWA results. METHODS AND RESULTS A total of 1003 patients hospitalized with decompensated HF were enrolled. MTWA testing was planned 1 month post-discharge; 648 patients returned for MTWA testing. Mean age was 70.8 ± 10.6 years and 58% were male. Of these patients who returned, 318 (49%) were ineligible for MTWA testing due to atrial fibrillation (AF), pacemaker dependency, or physical inability to undertake the test. Of the MTWA tests, 100 (30%) were positive, 78 (24%) were negative, and 152 (46%) were indeterminate; 112/152 indeterminate tests (74%) occurred because of failure to achieve target heart rate (HR) due to chronotropic incompetence or physical limitations. There were differences in patient characteristics according to MTWA result. Independent predictors of a negative result included younger age and higher left ventricular ejection fraction (LVEF). Independent predictors of a positive result included higher HR during MTWA testing and lower LVEF. Independent predictors of an indeterminate result included older age and history of previous/paroxysmal AF. CONCLUSIONS Only half of patients with HF are eligible for MTWA testing and the most common result is an indeterminate test. Patients with positive and indeterminate tests have different clinical characteristics. MTWA treadmill testing is not widely applicable in typical HF patients and is unlikely to refine risk stratification for sudden death on a population level.
Collapse
Affiliation(s)
- Colette E Jackson
- British Heart Foundation Cardiovascular Research Centre, University of Glasgow, 126 University Place, Glasgow, UK
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Correlation between T-Wave Alternans and Cardiac Volume Status via Intrathoracic Impedance Measurements. Case Rep Cardiol 2012; 2012:167562. [PMID: 24826235 PMCID: PMC4008472 DOI: 10.1155/2012/167562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/25/2012] [Indexed: 12/03/2022] Open
Abstract
Introduction. The presence of T-wave alternans (TWA) has been shown to correlate with a higher risk for sudden cardiac death. The mechanism of TWA may be related to abnormalities in intracellular calcium handling, which is a mechanism in heart failure and associated arrhythmias as well. However, an association between TWA and cardiac volume status has not been demonstrated.
Methods Used. We report the case of a 54-year-old man with a dilated cardiomyopathy who had a biventricular defibrillator system implanted with intrathoracic impedance measurement capability. We performed baseline TWA testing, which was normal and was associated with normal clinical status and normal intrathoracic impedance. We followed intrathoracic impedance measurements, and when the measurement suggested volume overload eight months later, we repeated the TWA test. TWA was grossly positive, and volume overload was corroborated with clinical heart failure. The patient was diuresed, and when clinical status and intrathoracic impedance returned to normal a month later, we repeated TWA, which was again negative.
Conclusion. This case demonstrates a correlation between cardiac volume status, as measured by intrathoracic impedance measurements, and TWA status. This data suggests that conditions of volume overload such as heart failure could be causally related to increased TWA, perhaps by the common mechanism of altered intracellular calcium handling.
Collapse
|
34
|
Verrier RL, Klingenheben T, Malik M, El-Sherif N, Exner DV, Hohnloser SH, Ikeda T, Martínez JP, Narayan SM, Nieminen T, Rosenbaum DS. Microvolt T-wave alternans physiological basis, methods of measurement, and clinical utility--consensus guideline by International Society for Holter and Noninvasive Electrocardiology. J Am Coll Cardiol 2011; 58:1309-24. [PMID: 21920259 DOI: 10.1016/j.jacc.2011.06.029] [Citation(s) in RCA: 286] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 06/10/2011] [Accepted: 06/13/2011] [Indexed: 10/17/2022]
Abstract
This consensus guideline was prepared on behalf of the International Society for Holter and Noninvasive Electrocardiology and is cosponsored by the Japanese Circulation Society, the Computers in Cardiology Working Group on e-Cardiology of the European Society of Cardiology, and the European Cardiac Arrhythmia Society. It discusses the electrocardiographic phenomenon of T-wave alternans (TWA) (i.e., a beat-to-beat alternation in the morphology and amplitude of the ST-segment or T-wave). This statement focuses on its physiological basis and measurement technologies and its clinical utility in stratifying risk for life-threatening ventricular arrhythmias. Signal processing techniques including the frequency-domain Spectral Method and the time-domain Modified Moving Average method have demonstrated the utility of TWA in arrhythmia risk stratification in prospective studies in >12,000 patients. The majority of exercise-based studies using both methods have reported high relative risks for cardiovascular mortality and for sudden cardiac death in patients with preserved as well as depressed left ventricular ejection fraction. Studies with ambulatory electrocardiogram-based TWA analysis with Modified Moving Average method have yielded significant predictive capacity. However, negative studies with the Spectral Method have also appeared, including 2 interventional studies in patients with implantable defibrillators. Meta-analyses have been performed to gain insights into this issue. Frontiers of TWA research include use in arrhythmia risk stratification of individuals with preserved ejection fraction, improvements in predictivity with quantitative analysis, and utility in guiding medical as well as device-based therapy. Overall, although TWA appears to be a useful marker of risk for arrhythmic and cardiovascular death, there is as yet no definitive evidence that it can guide therapy.
Collapse
Affiliation(s)
- Richard L Verrier
- Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Bhakta D, Foreman LD. Implantable cardioverter-defibrillator shock reduction: the new paradigm. Heart Rhythm 2011; 8:1887-8. [PMID: 21856274 DOI: 10.1016/j.hrthm.2011.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Indexed: 11/24/2022]
|
36
|
YAN GUOHUI, WANG MEI, YUE WENSHENG, YIU KAIHANG, ZHI GUANG, LAU CHUPAK, WL LEE STEPHEN, SIU CHUNGWAH, TSE HUNGFAT. Relationship between Ventricular Dyssynchrony and T-wave Alternans in Patients with Coronary Artery Disease. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2011; 34:1503-10. [DOI: 10.1111/j.1540-8159.2011.03183.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
37
|
Trzos E, Kasprzak JD, Krzemińska-Pakuła M, Rechciński T, Wierzbowska-Drabik K, Uznańska B, Śmiałowski A, Rudziński T, Kurpesa M. The prevalence and the prognostic value of microvolt T-wave alternans in patients with hypertrophic cardiomyopathy. Ann Noninvasive Electrocardiol 2011; 16:276-86. [PMID: 21762256 DOI: 10.1111/j.1542-474x.2011.00443.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Nonsustained ventricular tachycardia (nVT) may have ominous implications for patients with hypertrophic cardiomyopathy (HCM). The microvolt T-wave alternans (TWA) has been proposed as a noninvasive tool-identifying patients at risk of sudden cardiac death and ventricular tachycardia/fibrillation (VT/VF). The aim of the study was to determine the significance of TWA in predicting nVT episodes and compare how other electrocardiographic parameters can predict the occurrence of nVT. METHODS The study group consisted of 88 patients with HCM. TWA was assessed during exercise test using the CH2000 system. All patients underwent Holter monitoring (HM) within 2-4 weeks before TWA test (preexercise HM1) and immediately after (postexercise HM2). During HM, we analyzed: arrhythmias, QT intervals, the presence of late ventricular potentials (LP), heart rate variability, heart rate turbulence. RESULTS Depending on TWA results, the patients were divided into two groups: TWA+; 46 patients (52.3%) with positive/indeterminate results, and TWA-; 42 patients (47.7%) with negative results. The nVT episodes were more frequent among TWA(+) both in HM1 and HM2. The presence of TWA increases the risk of postexercise nVT over twenty times (OR = 21.03). Moreover, in HM1, QTc and LP, and in HM2, again QTc and N-terminal precursor of brain natriuretic peptide proved to be significant predictors of nVT. The addition of TWA to the models did not improve the arrhythmia risk assessment. CONCLUSIONS Repolarization abnormality plays an important role in generating nVT in patients with HCM, but TWA does not specifically predict the risk of arrhythmic end point.
Collapse
Affiliation(s)
- Ewa Trzos
- Department of Cardiology, Biegański Hospital, Medical University of Lodz, Lodz, Poland.
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Lopera G, Curtis AB. Risk stratification for sudden cardiac death: current approaches and predictive value. Curr Cardiol Rev 2011; 5:56-64. [PMID: 20066150 PMCID: PMC2803290 DOI: 10.2174/157340309787048130] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 07/05/2008] [Accepted: 07/05/2008] [Indexed: 11/22/2022] Open
Abstract
Sudden cardiac death (SCD) is a serious public health problem; the annual incidence of out-of-hospital cardiac arrest in North America is approximately 166,200. Identifying patients at risk is a difficult proposition. At the present time, left ventricular ejection fraction (LVEF) remains the single most important marker for risk stratification. According to current guidelines, most patients with LVEF <35% could benefit from prophylactic ICD implantation, particularly in the setting of symptomatic heart failure. Current risk stratification strategies fail to identify patients at risk of SCD in larger population groups encompassing a greater number of potential SCD victims. However, the best approach to identifying patients and the value of various risk stratification tools is not entirely clear. The goal of this review is to discuss the problem of SCD and the value of the different risk stratification markers and their potential clinical use either alone or in combination with other risk stratification markers.
Collapse
Affiliation(s)
- Gustavo Lopera
- Division of Cardiology, University of Miami/Miller School of Medicine, Miami, FL, USA
| | | |
Collapse
|
39
|
Fereniec M, Stix G, Kania M, Mroczka T, Janusek D, Maniewski R. Risk assessment of ventricular arrhythmia using new parameters based on high resolution body surface potential mapping. Med Sci Monit 2011; 17:MT26-33. [PMID: 21358612 PMCID: PMC3524725 DOI: 10.12659/msm.881436] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background The effective screening of myocardial infarction (MI) patients threatened by ventricular tachycardia (VT) is an important issue in clinical practice, especially in the process of implantable cardioverter-defibrillator (ICD) therapy recommendation. This study proposes new parameters describing depolarization and repolarization inhomogeneity in high resolution body surface potential maps (HR BSPM) to identify MI patients threatened by VT. Material/Methods High resolution ECGs were recorded from 64 surface leads. Time-averaged HR BSPMs were used. Several parameters for arrhythmia risk assessment were calculated in 2 groups of MI patients: those with and without documented VT. Additionally, a control group of healthy subjects was studied. To assess the risk of VT, the following parameters were proposed: correlation coefficient between STT and QRST integral maps (STT_QRST_CORR), departure index of absolute value of STT integral map (STT_DI), and departure index of absolute value of T-wave shape index (TSI_DI). These new parameters were compared to known parameters: QRS width, QT interval, QT dispersion, Tpeak-Tend interval, total cosines between QRS complex and T wave, and non-dipolar content of QRST integral maps. Results STT_DI, TSI_DI, STT_QRST_CORR, QRS width, and QT interval parameters were statistically significant (p≤0.05) in arrhythmia risk assessment. The highest sensitivity was found for the STT_DI parameter (0.77) and the highest specificity for TSI_DI (0.79). Conclusions Arrhythmia risk is demonstrated by both abnormal spatial distribution of the repolarization phase and changed relationship between depolarization and repolarization phases, as well as their prolongation. The proposed new parameters might be applied for risk stratification of cardiac arrhythmia.
Collapse
Affiliation(s)
- Malgorzata Fereniec
- Nalecz Institute of Biocybernetics and Biomedical Engineering PAS, Warsaw, Poland
| | | | | | | | | | | |
Collapse
|
40
|
Weiss EH, Merchant FM, d'Avila A, Foley L, Reddy VY, Singh JP, Mela T, Ruskin JN, Armoundas AA. A novel lead configuration for optimal spatio-temporal detection of intracardiac repolarization alternans. Circ Arrhythm Electrophysiol 2011; 4:407-17. [PMID: 21430127 DOI: 10.1161/circep.109.934208] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Electric alternans is a pattern of variation in the shape of ECG waveform that occurs every other beat. In humans, alternation in ventricular repolarization, known as repolarization alternans (RA), has been associated with increased vulnerability to ventricular tachycardia/fibrillation and sudden cardiac death. METHODS AND RESULTS This study investigates the spatio-temporal variability of intracardiac RA and its relationship to body surface RA in an acute myocardial ischemia model in swine. We developed a real-time multichannel repolarization signal acquisition, display, and analysis system to record ECG signals from catheters in the right ventricle, coronary sinus, left ventricle, and epicardial surface before and after circumflex coronary artery balloon occlusion. We found that RA is detectable within 4 minutes after the onset ischemia and is most prominently seen during the first half of the repolarization interval. Ischemia-induced RA was detectable on unipolar and bipolar leads (both in near- and far-field configurations) and on body surface leads. Far-field bipolar intracardiac leads were more sensitive for RA detection than body surface leads, with the probability of body surface RA detection increasing as the number of intracardiac leads detecting RA increased, approaching 100% when at least three intracardiac leads detected RA. We developed a novel, clinically applicable intracardiac lead system based on a triangular arrangement of leads spanning the right ventricular and coronary sinus catheters, which provided the highest sensitivity for intracardiac RA detection when compared with any other far-field bipolar sensing configurations. CONCLUSIONS In conclusion, intracardiac alternans, a complex spatio-temporal phenomenon associated with arrhythmia susceptibility and sudden cardiac death, can be reliably detected through a novel triangular right ventricular-coronary sinus lead configuration.
Collapse
Affiliation(s)
- Eric H Weiss
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Pedersen SS, den Broek KCV, Theuns DA, Erdman RA, Alings M, Meijer A, Jordaens L, Denollet J. Risk of chronic anxiety in implantable defibrillator patients: A multi-center study. Int J Cardiol 2011; 147:420-3. [DOI: 10.1016/j.ijcard.2009.09.549] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 08/21/2009] [Accepted: 09/01/2009] [Indexed: 11/16/2022]
|
42
|
Zhao J, Xie Y, Jiang R, Kan H, Song W. Effects of atorvastatin on fine particle-induced inflammatory response, oxidative stress and endothelial function in human umbilical vein endothelial cells. Hum Exp Toxicol 2011; 30:1828-39. [DOI: 10.1177/0960327111401050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The study is to explore the toxicity of organic extracts and water-soluble fraction of fine particles on human umbilical vein endothelial cells (HUVECs). The exposure doses were 100, 200 and 400 μg/ml, respectively, for two kinds of fractions. Moreover, atorvastatin was used for intervention study. HUVECs were stimulated by 400 μg/ml organic and water soluble extracts, respectively, immediately followed by treatment with atorvastatin in concentrations of 0.1 μmol/L, 1 μmol/L and 10 μmol/L, respectively. Cell viability, malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), reactive oxygen species (ROS) and the expression of interleukin-6 beta (IL-6), tumor necrosis factor-α (TNF-α), endothelin-1 and P-selectin were determined in cells. The results showed that MDA and ROS increased in HUVECs after exposed to organic extracts and water-soluble fraction, whereas cell viability, NO and SOD decreased. The mRNA expression of IL-6, TNF-α, endothelin-1 (ET-1) and P-selectin increased after exposed to different fractions. Meanwhile, at the same exposure dose, water-soluble fraction caused more significant increase of MDA, IL-6, TNF-α and P-selectin and decrease of cell viability and NO when compared to organic extracts. Compared to no atorvastatin group, the levels of MDA, ROS and the expression of IL-6, TNF-α, ET-1 and P-selectin decreased in HUVECs in adding atorvastatin group, but cell viability, NO and SOD increased, which indicated that atorvastatin attenuated fine particle-induced inflammatory response, oxidative stress and endothelial damage. The results hinted that the inflammatory response, oxidative stress and endothelial dysfunction might be the mechanisms of cardiovascular injury induced by different fractions of ambient fine particles.
Collapse
Affiliation(s)
- Jinzhuo Zhao
- Department of Environment Health, School of Public Health, Fudan University, The Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| | - Yuquan Xie
- Department of Cardiology, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China
| | - Rongfang Jiang
- Department of Environment Health, School of Public Health, Fudan University, The Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| | - Haidong Kan
- Department of Environment Health, School of Public Health, Fudan University, The Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| | - Weimin Song
- Department of Environment Health, School of Public Health, Fudan University, The Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| |
Collapse
|
43
|
Yodogawa K, Ohara T, Takayama H, Seino Y, Katoh T, Mizuno K. Detection of Prior Myocardial Infarction Patients Prone to Malignant Ventricular Arrhythmias Using Wavelet Transform Analysis. Int Heart J 2011; 52:286-9. [DOI: 10.1536/ihj.52.286] [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: 11/18/2022]
Affiliation(s)
- Kenji Yodogawa
- Division of Cardiology, Department of Internal Medicine, Nippon Medical School Chiba Hokusoh Hospital
| | - Toshihiko Ohara
- Division of Cardiology, Hepatology, Geriatrics, and Integrated Medicine, Department of Internal Medicine, Nippon Medical School
| | - Hideo Takayama
- Division of Cardiology, Hepatology, Geriatrics, and Integrated Medicine, Department of Internal Medicine, Nippon Medical School
| | - Yoshihiko Seino
- Division of Cardiology, Department of Internal Medicine, Nippon Medical School Chiba Hokusoh Hospital
| | - Takao Katoh
- Division of Cardiology, Hepatology, Geriatrics, and Integrated Medicine, Department of Internal Medicine, Nippon Medical School
| | - Kyoichi Mizuno
- Division of Cardiology, Hepatology, Geriatrics, and Integrated Medicine, Department of Internal Medicine, Nippon Medical School
| |
Collapse
|
44
|
Kanu UB, Iravanian S, Gilmour RF, Christini DJ. Control of action potential duration alternans in canine cardiac ventricular tissue. IEEE Trans Biomed Eng 2010; 58:894-904. [PMID: 21041155 DOI: 10.1109/tbme.2010.2089984] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cardiac electrical alternans, characterized by a beat-to-beat alternation in action potential waveform, is a naturally occurring phenomenon, which can occur at sufficiently fast pacing rates. Its presence has been putatively linked to the onset of cardiac reentry, which is a precursor to ventricular fibrillation. Previous studies have shown that closed-loop alternans control techniques that apply a succession of externally administered cycle perturbations at a single site provide limited spatially-extended alternans elimination in sufficiently large cardiac substrates. However, detailed experimental investigations into the spatial dynamics of alternans control have been restricted to Purkinje fiber studies. A complete understanding of alternans control in the more clinically relevant ventricular tissue is needed. In this paper, we study the spatial dynamics of alternans and alternans control in arterially perfused canine right ventricular preparations using an optical mapping system capable of high-resolution fluorescence imaging. Specifically, we quantify the spatial efficacy of alternans control along 2.5 cm of tissue, focusing on differences in spatial control between different subregions of tissue. We demonstrate effective control of spatially-extended alternans up to 2.0 cm, with control efficacy attenuating as a function of distance. Our results provide a basis for future investigations into electrode-based control interventions of alternans in cardiac tissue.
Collapse
Affiliation(s)
- Uche B Kanu
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA.
| | | | | | | |
Collapse
|
45
|
Sabir IN, Ma N, Jones VJ, Goddard CA, Zhang Y, Kalin A, Grace AA, Huang CLH. Alternans in genetically modified langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia. Front Physiol 2010; 1:126. [PMID: 21423368 PMCID: PMC3059940 DOI: 10.3389/fphys.2010.00126] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 07/29/2010] [Indexed: 11/23/2022] Open
Abstract
The relationship between alternans and arrhythmogenicity was studied in genetically modified murine hearts modeling catecholaminergic polymorphic ventricular tachycardia (CPVT) during Langendorff perfusion, before and after treatment with catecholamines and a β-adrenergic antagonist. Heterozygous (RyR2p/s) and homozygous (RyR2s/s) RyR2-P2328S hearts, and wild-type (WT) controls, were studied before and after treatment with epinephrine (100 nM and 1 μM) and propranolol (100 nM). Monophasic action potential recordings demonstrated significantly greater incidences of arrhythmia in RyR2p/s and RyR2s/s hearts as compared to WTs. Arrhythmogenicity in RyR2s/s hearts was associated with alternans, particularly at short baseline cycle lengths. Both phenomena were significantly accentuated by treatment with epinephrine and significantly diminished by treatment with propranolol, in full agreement with clinical expectations. These changes took place, however, despite an absence of changes in mean action potential durations, ventricular effective refractory periods or restitution curve characteristics. Furthermore pooled data from all hearts in which arrhythmia occurred demonstrated significantly greater alternans magnitudes, but similar restitution curve slopes, to hearts that did not demonstrate arrhythmia. These findings thus further validate the RyR2-P2328S murine heart as a model for human CPVT, confirming an alternans phenotype in common with murine genetic models of the Brugada syndrome and the congenital long-QT syndrome type 3. In contrast to these latter similarities, however, this report demonstrates the dissociation of alternans from changes in the properties of restitution curves for the first time in a murine model of a human arrhythmic syndrome.
Collapse
Affiliation(s)
- Ian N Sabir
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge Cambridge, UK.
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Matthews GDK, Martin CA, Grace AA, Zhang Y, Huang CLH. Regional variations in action potential alternans in isolated murine Scn5a (+/-) hearts during dynamic pacing. Acta Physiol (Oxf) 2010; 200:129-46. [PMID: 20384594 DOI: 10.1111/j.1748-1716.2010.02138.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIM clinical observations suggest that alternans in action potential (AP) characteristics presages breakdown of normal ordered cardiac electrical activity culminating in ventricular arrhythmogenesis. We compared such temporal nonuniformities in monophasic action potential (MAP) waveforms in left (LV) and right ventricular (RV) epicardia and endocardia of Langendorff-perfused murine wild-type (WT), and Scn5a(+/-) hearts modelling Brugada syndrome (BrS) for the first time. METHODS a dynamic pacing protocol imposed successively incremented steady pacing rates between 5.5 and 33 Hz. A signal analysis algorithm detected sequences of >10 beats showing alternans. Results were compared before and following the introduction of flecainide (10 microm) and quinidine (5 microm) known to exert pro- and anti-arrhythmic effects in BrS. RESULTS sustained and transient amplitude and duration alternans were both frequently followed by ventricular ectopic beats and ventricular tachycardia or fibrillation. Diastolic intervals (DIs) that coincided with onsets of transient (tr) or sustained (ss) alternans in MAP duration (DI*) and amplitude (DI') were determined. Kruskal-Wallis tests followed by Bonferroni-corrected Mann-Whitney U-tests were applied to these DI results sorted by recording site, pharmacological conditions or experimental populations. WT hearts showed no significant heterogeneities in any DI. Untreated Scn5a (+/-) hearts showed earlier onsets of transient but not sustained duration alternans in LV endocardium compared with RV endocardium or LV epicardium. Flecainide administration caused earlier onsets of both transient and sustained duration alternans selectively in the RV epicardium in the Scn5a (+/-) hearts. CONCLUSION these findings in a genetic model thus implicate RV epicardial changes in the arrhythmogenicity produced by flecainide challenge in previously asymptomatic clinical BrS.
Collapse
Affiliation(s)
- G D K Matthews
- Physiological Laboratory, University of Cambridge, Cambridge
| | | | | | | | | |
Collapse
|
47
|
Patel RB, Ng J, Reddy V, Chokshi M, Parikh K, Subacius H, Alsheikh-Ali AA, Nguyen T, Link MS, Goldberger JJ, Ilkhanoff L, Kadish AH. Early Repolarization Associated With Ventricular Arrhythmias in Patients With Chronic Coronary Artery Disease. Circ Arrhythm Electrophysiol 2010; 3:489-95. [DOI: 10.1161/circep.109.921130] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Ravi B. Patel
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Jason Ng
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Vikram Reddy
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Moulin Chokshi
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Kishan Parikh
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Haris Subacius
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Alawi A. Alsheikh-Ali
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Tuan Nguyen
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Mark S. Link
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Jeffrey J. Goldberger
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Leonard Ilkhanoff
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| | - Alan H. Kadish
- From the Division of Cardiology (R.B.P., J.N., V.R., M.C., K.P., H.S., J.J.G., L.I., A.H.K.), Feinberg School of Medicine, Northwestern University, Chicago, Ill; the Division of Cardiology (A.A.A.-A., T.N., M.S.L.), Tufts Medical Center, Tufts University School of Medicine, Boston, Mass; and the Institute of Cardiac Sciences (A.A.A.-A.), Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates
| |
Collapse
|
48
|
Lőrincz I, Szánthó E, Simkó J, Szabó Z, Barta K, Füzi M, Szigeti G. Microvolt T-wave alternant: pathomechanism and evaluation of a new marker of arrhythmia risk. Orv Hetil 2010; 151:1215-24. [DOI: 10.1556/oh.2010.28926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A mikrovolt T-hullám-alternáns, angolul microvolt T-wave alternant (µV-TWA), a T-hullám amplitúdójának ütésről ütésre történő mikrovoltszinten mérhető váltakozása. Mivel ez a változás igen kicsi, csak finom, érzékeny digitális jelfeldolgozó technikával mérhető. Jelenlegi álláspont szerint a µV-TWA megjelenése előre jelezheti a letális, malignus kamrai tachyarrythmiák kialakulásának valószínűségét, a hirtelen szívhalál bekövetkeztét. Az elmúlt tíz évben experimentális és klinikai vizsgálatok próbálták magyarázni a µV-TWA kialakulásának patomechanizmusát és a mögöttes sejtszintű folyamatokat. Azonban a mai napig nem sikerült a µV-TWA-t kialakító celluláris folyamatokat megfelelően tisztázni. Összefoglaló tanulmányunkban áttekintjük azokat a témával foglalkozó közleményeket, amelyek a folyamatban szerepet játszó akciós potenciál repolarizációjában fontosak voltak és áttörést jelentettek az elmúlt években. Részletezzük az akciós potenciál és ionáram-fluktuáció, a citoplazmatikus kalciumkoncentráció-szabályozás, a béta-adrenerg receptorok, valamint a connexinek szerepét a µV-TWA és a következményes kamrai tachyarrhythmiák kialakításában. Ismertetjük továbbá a µV-TWA detektálására jelenleg alkalmazott technikákat, azok felhasználási lehetőségeit a hirtelen szívhalál veszélyeztetettségének felmérésében.
Collapse
Affiliation(s)
- István Lőrincz
- 1 Debreceni Egyetem, Orvos- és Egészségtudományi Centrum I. Belgyógyászati Klinika, Sürgősségi Orvostan Tanszék Debrecen Nagyerdei krt. 98. Pf. 19 4032
| | - Eszter Szánthó
- 1 Debreceni Egyetem, Orvos- és Egészségtudományi Centrum I. Belgyógyászati Klinika, Sürgősségi Orvostan Tanszék Debrecen Nagyerdei krt. 98. Pf. 19 4032
| | - József Simkó
- 2 Miskolci Semmelweis Ignác Egészségügyi Központ és Egyetemi Oktatókórház Nonprofit Kft. Belgyógyászati Intézet, Kardiológiai Osztály Miskolc
| | - Zoltán Szabó
- 1 Debreceni Egyetem, Orvos- és Egészségtudományi Centrum I. Belgyógyászati Klinika, Sürgősségi Orvostan Tanszék Debrecen Nagyerdei krt. 98. Pf. 19 4032
| | - Kitti Barta
- 1 Debreceni Egyetem, Orvos- és Egészségtudományi Centrum I. Belgyógyászati Klinika, Sürgősségi Orvostan Tanszék Debrecen Nagyerdei krt. 98. Pf. 19 4032
| | - Márta Füzi
- 1 Debreceni Egyetem, Orvos- és Egészségtudományi Centrum I. Belgyógyászati Klinika, Sürgősségi Orvostan Tanszék Debrecen Nagyerdei krt. 98. Pf. 19 4032
| | | |
Collapse
|
49
|
Liew R, Chiam PTL. Risk Stratification for Sudden Cardiac Death after Acute Myocardial Infarction. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2010. [DOI: 10.47102/annals-acadmedsg.v39n3p237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Many patients who survive an acute myocardial infarction (AMI) remain at risk of recurrent cardiac events and sudden cardiac death after discharge, despite optimal medical treatment. Assessment of the degree of left ventricular dysfunction and residual myocardial ischaemia is useful to identify the patients at greatest risk. In addition, there is increasing evidence that a number of other cardiovascular tests can be used to detect autonomic dysfunction and myocardial substrate abnormalities postAMI that increase the risk of life-threatening ventricular arrhythmias. These investigations include ECG-based tests (signal averaged ECG and T-wave alternans), Holter-based recordings (heart rate variability and heart rate turbulence) and imaging techniques echocardiography and cardiac magnetic resonance), as well as invasive electrophysiological testing. This article reviews the current evidence for the use of these additional cardiac investigations among survivors of AMI to aid in their risk stratification for malignant ventricular arrhythmias and sudden cardiac death.
Key words: Electrophysiological study, Holter recording, Non-invasive tests, Ventricular tachycardia
Collapse
|
50
|
Martin DT, Shoraki A, Nesto RW, Rutter MK. Influence of diabetes and/or myocardial infarction on prevalence of abnormal T-wave alternans. Ann Noninvasive Electrocardiol 2010; 14:355-9. [PMID: 19804512 DOI: 10.1111/j.1542-474x.2009.00325.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Subjects with microvolt-level T-wave alternans (TWA) in association with structural heart disease have an increased risk for sudden cardiac death. The presence of diabetes (DM) is associated with an increased risk of sudden death but there is limited data on the impact of DM and previous myocardial infarction (MI) on TWA prevalence. METHODS We performed a case-control cross-sectional study in 140 patients referred for routine exercise testing within a large multispecialty clinic. All patients with a history of DM and MI status within the past year were eligible: group 1 (no DM or MI), group 2 (DM only), group 3 (MI only), group 4 (DM and MI). Patients performed a symptom-limited Bruce protocol exercise test with assessment of TWA by the spectral method using commercially available equipment. We used published criteria for the blinded interpretation of TWA; all tests not unequivocally negative were considered abnormal. RESULTS Age and gender were similar in all groups. The prevalence of abnormal TWA in groups 1-4 was 24%, 20%, 48%, and 62%, respectively (between group P = 0.002). Logistic regression analysis in all patients showed that abnormal TWA was related to prior MI [OR (95% CI): 4.0 (1.8-8.9), P < 0.001] but not to prevalent DM [0.9 (0.4-1.8), P = 0.72]. In patients with DM, the prevalence of abnormal TWA was related to reduced ejection fraction (P = 0.034) but not to BMI, DM duration, glycemic control, insulin use, or the presence of microvascular complications. CONCLUSION The presence of DM alone does not increase risk of abnormal TWA. Prospective studies are required to establish the prognostic value of TWA in patients with DM.
Collapse
Affiliation(s)
- David T Martin
- Department of Cardiovascular Medicine, Lahey Clinic Medical Center, Burlington, MA 01805, USA.
| | | | | | | |
Collapse
|