Survival benefit of ICD implantation for primary prevention in dilated cardiomyopathy

Abstract

Objectives: Dilated cardiomyopathy (DCM) represents a significant cause of heart failure unrelated to ischemic heart disease, posing a high risk of sudden cardiac death (SCD) due to low left ventricular ejection fraction (LVEF). This study evaluates the survival benefits of implantable cardiac defibrillators (ICDs) for primary prevention in DCM patients. Methods: We enrolled 52 symptomatic non-ischemic cardiomyopathy patients (LVEF ≤ 35%, NYHA class II-III) eligible for ICD implantation in Afshar Hospital, Yazd, Iran, from 2014 to 2015. Exclusion criteria included those with ischemic indications or requiring cardiac resynchronization therapy. We divided patients into ICD recipients and those on a waiting list, collected the baseline data (age, functional class, LVEF), then followed up with patients to assess mortality rates. Results: Among 45 patients, 64.5% received ICDs while 35.5% were on the waiting list. The mean age was 57±13 years, predominantly male (67.3%). The ICD group had a significantly lower mortality rate (17.3%) than the waiting list group (42.7%, p = 0.54). Although age and functional class did not significantly predict outcomes, lower LVEF was a crucial factor for long-term survival. Despite some studies suggesting no survival benefit in non-ischemic heart failure, our findings highlight the efficacy of ICDs in reducing mortality among DCM patients. Conclusions: ICD implantation in DCM patients substantially reduces all-cause mortality compared to those awaiting the procedure, underscoring the importance of timely ICD deployment for primary prevention in this population.