Mortality Rates and Clinical Predictors of Reduced Survival After Cardioverter Defibrillator Implantation

We aimed to identify mortality rates and clinical predictors of reduced survival in a large cohort of patients after implantation of an implantable cardioverter-defibrillator (ICD). Although existing data from clinical trials report annual mortality after ICD implantation from 2% to 9%, there are few data available on mortality rates or predictors of reduced survival in this patient population in clinical practice. In this single-center, retrospective analysis of 286 patients who underwent ICD implantation between June 1, 2000 and December 30, 2003, candidate predictors of mortality were assessed and subjected to multivariable analysis. Outcomes were documented using the Social Security Death Master File and hospital medical records. Overall annualized mortality was 11.3% after ICD implantation. Mortality rates in patients with left ventricular ejection fraction (LVEF) <25% were 27.2% at 1 year and 50.5% at 3 years. Digoxin (hazard ratio 1.86, 95% confidence interval [CI] 1.21 to 2.86, p = 0.0046) and loop diuretics (hazard ratio 1.59, 95% CI 1.06 to 2.38, p = 0.024) were associated with reduced survival. Angiotensin-converting enzyme inhibitor or aldosterone receptor blocker use was associated with reduced mortality (hazard ratio 0.50, 95% CI 0.31 to 0.80, p = 0.0038). In conclusion, mortality after ICD implantation is higher than demonstrated in primary or secondary prevention ICD trials; LVEF remains a potent predictor of mortality after ICD implantation, particularly in patients with an LVEF <25%; loop diuretic and digoxin use is associated with an approximate twofold increase in mortality in this population; and angiotensin-converting enzyme inhibitor or aldosterone receptor blocker use is associated with improved survival after ICD implantation.