Avi Sabbag1, Michael Glikson2, Mahmoud Suleiman3, Monther Boulos3, Ilan Goldenberg4, Roy Beinart5, Eyal Nof5. 1. Davidai Arrhythmia Center, Leviev Heart Center, Sheba Medical Center Ramat Gan, Tel Hashomer, and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel. Electronic address: Dr.Sabbag.avi@gmail.com. 2. Shaare Zedek Medical Center, Jerusalem, Israel. 3. Cardiology Department, Rambam Health Care Campus, Haifa, Israel. 4. Clinical Cardiovascular Research Center Cardiology Division, University of Rochester Medical Center, Rochester, New York. 5. Davidai Arrhythmia Center, Leviev Heart Center, Sheba Medical Center Ramat Gan, Tel Hashomer, and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
Abstract
BACKGROUND: The clinical benefit of primary prevention implantable cardioverter-defibrillator (ICD) therapy in asymptomatic patients (New York Heart Association [NYHA] functional class I) with ischemic cardiomyopathy and left ventricular dysfunction is continually disputed. OBJECTIVE: The purpose of this study was to evaluate the incidence of ventricular arrhythmias, mortality rates, and appropriate device therapies by NYHA class in a prospective national ICD registry. METHODS: The study comprised 1670 consecutive patients with ischemic cardiomyopathy who were implanted with a primary prevention ICD and enrolled in the prospective national Israeli ICD Registry from 2010. The risk for clinical and arrhythmic events was assessed by NYHA class. RESULTS: Asymptomatic patients (NYHA I) composed 19% of the study cohort. Comparison according to NYHA class showed that the highest mortality rate was in the NYHA III-IV group vs NYHA I and NYHA II (10.5% vs 5.4% and 5.8%, respectively; log rank P = .003). Conversely, cumulative incidence of appropriate ICD therapies, corrected for death as a competing risk, were higher among patients with NYHA I (11% vs 7%; P = .021). In a multivariate model, NYHA I vs ≥II remained independently associated with a significant 2-fold risk for appropriate ICD therapy (hazard ratio 2.03; 95% confidence interval 1.28-3.24). CONCLUSION: Our findings indicate that patients with ischemic cardiomyopathy without heart failure symptoms have a higher risk of appropriate ICD therapy compared with symptomatic patients after adjustment for the competing risk of death, suggesting possible incremental benefit of primary ICD implantation in this population.
BACKGROUND: The clinical benefit of primary prevention implantable cardioverter-defibrillator (ICD) therapy in asymptomatic patients (New York Heart Association [NYHA] functional class I) with ischemic cardiomyopathy and left ventricular dysfunction is continually disputed. OBJECTIVE: The purpose of this study was to evaluate the incidence of ventricular arrhythmias, mortality rates, and appropriate device therapies by NYHA class in a prospective national ICD registry. METHODS: The study comprised 1670 consecutive patients with ischemic cardiomyopathy who were implanted with a primary prevention ICD and enrolled in the prospective national Israeli ICD Registry from 2010. The risk for clinical and arrhythmic events was assessed by NYHA class. RESULTS: Asymptomatic patients (NYHA I) composed 19% of the study cohort. Comparison according to NYHA class showed that the highest mortality rate was in the NYHA III-IV group vs NYHA I and NYHA II (10.5% vs 5.4% and 5.8%, respectively; log rank P = .003). Conversely, cumulative incidence of appropriate ICD therapies, corrected for death as a competing risk, were higher among patients with NYHA I (11% vs 7%; P = .021). In a multivariate model, NYHA I vs ≥II remained independently associated with a significant 2-fold risk for appropriate ICD therapy (hazard ratio 2.03; 95% confidence interval 1.28-3.24). CONCLUSION: Our findings indicate that patients with ischemic cardiomyopathy without heart failure symptoms have a higher risk of appropriate ICD therapy compared with symptomatic patients after adjustment for the competing risk of death, suggesting possible incremental benefit of primary ICD implantation in this population.