Implantable cardioverter-defibrillator in patients with hypertrophic cardiomyopathy: efficacy and complications of the therapy in long-term follow-up.

INTRODUCTION: Although implantable cardioverter-defibrillators (ICDs) are used in sudden cardiac death (SCD) prevention in high-risk patients with hypertrophic cardiomyopathy (HCM), long-term results as well as precise risk stratification are discussed in a limited number of reports. The aim of the study was to assess the incidence of ICD intervention in HCM patients with relation to clinical risk profile.

METHODS AND RESULTS: We studied 104 consecutive patients with HCM implanted in a single center. The mean age of study population was 35.6 (SD, 16.2) years with the average follow-up of 4.6 (SD, 2.6) years. ICD was implanted for secondary (n = 26) and primary (n = 78) prevention of SCD. In the secondary prevention group, 14 patients (53.8%) experienced at least 1 appropriate device intervention (7.9%/year). In the primary prevention (PP) group appropriate ICD discharges occurred in 13 patients (16.7%) and intervention rate was 4.0%/year. Nonsustained VT was the only predictive risk factor (RF) for an appropriate ICD intervention in the PP (positive predictive value 22%, negative predictive value 96%). No significant difference was observed in the incidence of appropriate ICD discharges between PP patients with 1, 2, or more RF. Complications of the treatment included: inappropriate shocks (33.7%), lead dysfunction (12.5%), and infections: 4.8% of patients. Four patients died during follow-up.

CONCLUSION: ICD therapy is effective in SCD prevention in patients with HCM, although the complication rate is significant. Nonsustained ventricular tachycardia seems to be the most predictive RF for appropriate device discharges. Number of RF did not impact the incidence of appropriate ICD interventions.