Risk of Sudden Death in Patients With RASopathy Hypertrophic Cardiomyopathy.

Background: Genetic defects in the RAS/mitogen-activated protein kinase pathway are an important cause of hypertrophic cardiomyopathy (RAS-HCM). Unlike primary HCM (P-HCM), the risk of sudden cardiac death (SCD) and long-term survival in RAS-HCM are poorly understood.
Objectives: The study's objective was to compare transplant-free survival, incidence of SCD, and implantable cardioverter-defibrillator (ICD) use between RAS-HCM and P-HCM patients.
Methods: In an international, 21-center cohort study, we analyzed phenotype-positive pediatric RAS-HCM (n = 188) and P-HCM (n = 567) patients. The between-group differences in cumulative incidence of all outcomes from first evaluation were compared using Gray's tests, and age-related hazard of all-cause mortality was determined.
Results: RAS-HCM patients had a lower median age at diagnosis compared to P-HCM (0.9 years [IQR: 0.2-5.0 years] vs 9.8 years [IQR: 2.0-13.9 years], respectively) (P < 0.001). The 10-year cumulative incidence of SCD from first evaluation was not different between RAS-HCM and P-HCM (4.7% vs 4.2%, respectively; P = 0.59). The 10-year cumulative incidence of nonarrhythmic deaths or transplant was higher in RAS-HCM compared with P-HCM (11.0% vs 5.4%, respectively; P = 0.011). The 10-year cumulative incidence of ICD insertions, however, was 5-fold lower in RAS-HCM compared with P-HCM (6.9% vs 36.6%; P < 0.001). Nonarrhythmic deaths occurred primarily in infancy and SCD primarily in adolescence.
Conclusions: RAS-HCM was associated with a higher incidence of nonarrhythmic death or transplant but similar incidence of SCD as P-HCM. However, ICDs were used less frequently in RAS-HCM compared to P-HCM. In addition to monitoring for heart failure and timely consideration of advanced heart failure therapies, better risk stratification is needed to guide ICD practices in RAS-HCM.
Competing Interests: Funding Support and Author Disclosures The project was supported through funding from the Ted Rogers Centre for Heart Research, the Heart and Stroke Foundation/Robert M Freedom Chair, and the Canadian Institutes of Health Research to Dr Mital. Dr Lynch is supported by a Heart Failure Research Fellowship from Bristol Myers Squibb, Mitacs, and Myant. Dr Mital has served as a consultant for Bristol Myers Squibb and Tenaya Therapeutics; and has received unrestricted education funding from Bristol Myers Squibb. Dr Conway has served as a medical monitor for the PumpKIN trial; and has received unrestricted education funding from Abbott. Dr Rossano has served as a consultant for Merck, Bayer, Myokardia, and Cytokinetics. Dr Kantor has served as a consultant for Novartis and AstraZeneca. Dr Balaji has served as a consultant for Milestone Pharmaceuticals and Janssen Pharmaceuticals; and has received a research support grant from the Medtronic External Research Program. Dr Godown has served as a consultant for Daiichi-Sankyo. Dr Aziz has served on the Medical Advisory Board for Medtronic. Dr Jeewa has served as a medical monitor for the PumpKIN trial; and has served as a consultant for Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)