CHANGING PROFILE OF YOUNG PATIENTS WITH HYPERTROPHIC CARDIOMYOPATHY RECEIVING IMPLANTABLE CARDIOVERTER DEFIBRILLATORS

Abstract

BACKGROUND: Implantable cardioverter defibrillator (ICD) therapy is increasingly -utilized for prevention of sudden cardiac death (SCD) in young patients with hypertrophic cardiomyopathy. The indications and ICD technology have changed significantly over the past 20 years, with downsized generators and leads more suitable for smaller patients. OBJECTIVE: Describe changes in pattern of implant indications and appropriate therapies during the last two decades in young HCM patients. METHODS: Multicenter and retrospective review of young HCM patients who underwent ICD implant for HCM. RESULTS: 120 HCM patients 21 years of age (14.2 years [0.9-21.8]) who underwent ICD implant between 1990 and 2010 were included. During a median follow up of 2.4 years (0.1-13.4), 7 patients died and 7 underwent heart transplant. Appropriate and inappropriate therapies were delivered in 33/120 patients (28%) and 37/120 (31%), respectively. Freedom from appropriate shocks at 2, 4 and 6 years was 37%, 19% and 19% for secondary prevention patients (n1⁄424) compared to 84%, 72% and 63% for primary prevention patients (n1⁄496). Patients were divided according to decade of ICD implant date ([1990-2000] and [20012010]). Secondary prevention indications decreased between the two decades (34% vs 12%, p<0.01). For primary prevention patients, time from diagnosis to implant was longer (4.2 vs 1.8 yrs, p1⁄40.02) and age at implant was older (14.3 vs 12.6 yrs, p1⁄40.04) in the recent era compared to the older era. This occurred despite similar SCD risk profiles using classic risk factors (p1⁄40.7). Time to first appropriate shock for primary prevention patients was shorter in the earlier era (p1⁄40.04). CONCLUSION: Over the last 20 years, ICD implant in young HCM patients for primary prevention has increased. Risk scores are comparable between both decades, suggesting an increase in number of patients referred for primary prevention ICD implant rather than broadening of indications.