Abstract 5695: Arrhythmogenic Cardiac Death in Implantable Cardioverter Defibrillator Recipients: A Long-term Study of 783 Consecutive Patients

Abstract

Introduction: Long-term mortality and cause of mortality of ICD recipients who are not enrolled in controlled clinical trials are not well known. This study seeked to determine cause-specific mortality in a large sample of unselected ICD recipients.

Methods: Consecutive ICD recipients followed at a tertiary referral center at regular 3-month intervals were included. In cases of missed visits, pts, their relatives and their family physicians were contacted. Based on all available evidence, causes of death were classified as cardiac arrhythmic (C–A), cardiac non-arrhythmic (C-NA), non cardial (non-C) and unknown.

Results: A total of 783 pts (primary prevention of sudden death in 252, secondary prevention in 531) were followed for 43 ± 30 months, during which time 193 pts died (24.7%, annual mortality 6.7%). Causes of death are shown in the figure⇓. Cox regression analysis revealed that all-cause morality was significantly affected by age (odds ratio 1.03, 95% confidence interval 1.01–1.05), LVEF (0.98, 0.96 – 0.99), NYHA > II (2.1, 1.35–3.26) at baseline, while ICD indication and development of electrical storm had no independent impact on all cause mortality. Predictors for arrhythmic mortality were LVEF (0.96, 0.91– 0.99), NYHA > II (5.3, 1.4 –19.6) spontaneous VT (9.9, 2.1– 45.2) or inducible VT (9.5, 2.0 – 44.2) as indication for ICD therapy.

Conclusion: In this unselected group of ICD recipients the mortality over 3.5 years was 25 %. Despite device therapy, at least 14% of patients died from presumably arrhythmic causes. Risk factors associated with arrhythmic mortality were a history of spontaneous or inducible monomorphic ventricular tachycardia, LVEF and higher NYHA class.