Predictors of early mortality in implantable cardioverter-defibrillator recipients

Abstract

Aims: Multiple trials have shown that implantable cardioverter defibrillators (ICDs) prolong survival in secondary and primary prevention populations. However, in spite of the efficacy of these devices in terminating life-threatening arrhythmias, total mortality remains high.

Methods and results: We evaluated 1703 patients (mean age: 67 +/- 12 years, 82% male) with conventional ICD indications, who were enrolled and followed between 2001 and 2004 at 128 US centres. Patients were followed for up to a year, and vital status was obtained for 1655 patients (97%, median follow-up: 377 days). There were 183 deaths within 1 year of ICD implantation (1-year mortality rate: 16%). Predictors of mortality included a history of atrial fibrillation (AF, P < 0.0001), diabetes (P = 0.0001), failure to use cholesterol-lowering medications (P < 0.001), use of digitalis and derivatives (P < 0.0001), use of diuretics (P < 0.0001), low body mass index (BMI, P < 0.0001), increasing age (P < 0.0001), low left ventricular ejection fraction (P < 0.0001), low activity hours (P < 0.0001), elevated resting heart rate (P = 0.014), low mean arterial pressure (MAP, P = 0.007), and poor functional status (New York Heart Association class, P < 0.0001). In multivariate modelling, AF (P < or = 0.001), diabetes (P = 0.004), BMI (P = 0.001), MAP (P = 0.040), and functional class (P = 0.006) predicted mortality.

Conclusion: In this population undergoing ICD implantation, poor functional status, low MAP, diabetes, low BMI, and AF were strongly associated with death within a year.