Effect of beta-blockers and exercise restriction on the prevention of sudden cardiac death in pediatric hypertrophic cardiomyopathy

Background: Risk assessment tools and effective prevention strategies for sudden cardiac death (SCD) in pediatric patients with hypertrophic cardiomyopathy (HCM) have not been established. This study aimed to evaluate the efficacy of beta-blockers and exercise restriction for SCD prevention in this population. Methods: We retrospectively reviewed the medical records of patients aged <18 years who were diagnosed with HCM at our center between January 1996 and December 2021. SCD and aborted SCD were de fined as SCD equivalents. We divided patients based on whether they were prescribed beta-blockers or exercise restriction and compared the outcomes among the groups. The primary outcome was the overall survival (OS), and the secondary outcome was the cumulative SCD equivalent rate. Outcomes were analyzed using Kaplan-Meier curves and Cox proportional hazard analysis. We also compared patients according to the occurrence of SCD equivalents to identify SCD risk predictors. Results: Among the 43 included patients [mean age, 7.7 (1.6-12.1) years; 23 male individuals], SCD equivalents occurred in 13 patients over 11.2 (4.5-15.6) years of follow-up, among whom 12 were resuscitated and 1 died. The OS rate was significantly higher in the beta-blocker and exercise restriction groups than in the non-betablocker and non-exercise restriction groups (81.3 % vs. 19.1 %, p < 0.01 and 57.4 % vs. 12.7 %, p < 0.01, respectively). Among the 13 patients with SCD equivalents, 5 had 9 recurrent SCD equivalents. A significant difference was observed between the SCD equivalent and non-SCD equivalent groups in the history of suspected arrhythmogenic syncope ( p < 0.01) in the univariable but not in the multivariable analysis. Conclusions: Beta-blockers and exercise restriction may decrease the risk of SCD in pediatric patients with HCM and should be considered for SCD prevention in this population, particularly because predicting SCD in these patients remains challenging. (c) 2023 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.