Abstract 9202: Sudden Cardiac Death and Icd Use in Rasopathy-Associated Hypertrophic Cardiomyopathy: An International Multi-Centre Study

Abstract

Introduction: Sudden cardiac death (SCD) burden in RASopathy patients (pts) with hypertrophic cardiomyopathy (RAS-HCM) is not known. We compared SCD events and transplant-free survival in RAS versus primary HCM (P-HCM) pts. Methods: The international 22-center retrospective cohort study (PRIMaCY) included 190 pediatric RAS-HCM and 568 P-HCM pts. The primary outcome was 10-year freedom from SCD events (composite of SCD, resuscitated sudden cardiac arrest, and appropriate shock from a prophylactic ICD), estimated using Kaplan Meier method. Results: Of 190 RAS-HCM pts, 82% had Noonan syndrome. Age at diagnosis was lower in RAS-HCM vs P-HCM (0.9 vs 9.7 yrs, p<0.001). There was no difference in baseline LV posterior wall or septal thickness, but LVOT gradient was higher in RAS-HCM vs P-HCM (30 vs 13mmHg, p<0.001). However, frequency of myectomy was not different in RAS-HCM vs P-HCM (15.2% vs 16.7%, p=0.55). Eighteen RAS-HCM pts died (4 SCD, 2 bradycardic arrests, 5 heart failure, 3 respiratory failure, 2 other) with lower 10-year transplant-free survival in RAS-HCM vs P-HCM (84.2% vs 91.6%, p=0.026). Although 10-year cumulative proportion of SCD events was lower in RAS-HCM than P-HCM (5.4% vs 15.1% respectively, p<0.001) (Figure 1), the median age at event was not different (12yrs in RAS-HCM vs 15.2yrs in P-HCM). Of 5 RAS-HCM pts with a SCD event, 4 died and 1 received a secondary prevention ICD. An additional 10 pts received a prophylactic ICD with no appropriate shock during follow-up. The 10-year cumulative proportion of prophylactic ICD was lower at 6.3% in RAS-HCM vs 27.2% in P-HCM (p<0.001). Conclusion: Transplant-free survival was lower in RAS-HCM than P-HCM with mortality related primarily to non-SCD events. Of the RAS-HCM patients with SCD events, 4 died without an ICD highlighting the need for better risk prediction models for both SCD and heart failure mortality in this population.