Efficacy of primary preventive ICD therapy in an unselected population of patients with reduced left ventricular ejection fraction

Abstract

Aims: International guidelines advocate an implantable cardioverter and defibrillator (ICD) in patients with reduced left ventricular ejection fraction (LVEF) to prevent sudden death (SCD). Previous data suggest that the benefit of ICD therapy in real life may be lower than expected from the results of controlled studies and side-effects are not negligible. It is also unclear whether women benefit from treatment to the same extent as men. The aim of this study was to investigate the balance between benefits and complications of ICD therapy in a real-life population of patients with heart failure.

Methods and results: We studied 865 consecutive patients with reduced LVEF treated with ICDs for primary prevention of SCD in 2006-11 in four tertiary care hospitals in Sweden (age 64 ± 11 years, 82% men, 62% ischaemic). The patients' medical records were scrutinized as regards appropriate therapies, complications related to the defibrillator, all-cause mortality, and gender differences. Mean follow-up was 35 ± 18 months. During follow-up 155 patients (18%) received appropriate ICD therapy, 61 patients (7%) had inappropriate shocks, 110 patients (13%) had at least one complication that required reoperation and 213 patients (25%) died. Men were twice as likely to receive ICD treatment compared with women (20 vs. 9%, P < 0.01), but neither total mortality nor complication rates differed.

Conclusions: Ventricular arrhythmias necessitating ICD therapy are common (6% annually). Women are less likely to have correct ICD treatment, but have the same degree of treatment complications, thus reducing the net benefit of their treatment.

Keywords: Appropriate therapy; Complications; Gender differences; Primary preventive defibrillator.