Validation of Guideline Recommendation on Sudden Cardiac Death Prevention in Hypertrophic Cardiomyopathy.

BACKGROUND

To prevent sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM), the HCM Risk-SCD calculator and guideline recommendations are used to aid decision making for implantable cardioverter-defibrillator placement.

OBJECTIVES

The aim of this study was to assess the clinical profiles and occurrence of SCD by phenotypes of HCM and validate the performance of the current guidelines from a large-scale Japanese multicenter registry.

METHODS

This was a retrospective, multicenter, observational, longitudinal cohort study that enrolled 3,611 consecutive patients with HCM. The primary endpoint was a composite of SCD or an equivalent event.

RESULTS

The 5-year cumulative incidence of SCD events was markedly high in patients with end-stage HCM, defined by ejection fraction <50% (18.5%), followed by midventricular obstruction and nonobstructive HCM (6.9% and 4.7%). The 5-year cumulative incidence rates of SCD events for each recommendation class by the 2 guidelines were as follows: with the 2024 ACC (American College of Cardiology)/AHA (American Heart Association) guidelines, 23.8%, 7.2%, 5.7%, and 2.3% for Classes 1, 2a, 2b, and 3, respectively, and with the 2023 ESC (European Society of Cardiology) guidelines, 23.8%, 2.9%, 9.3%, and 2.6%, respectively. The 5-year risk was not well stratified between Classes 2a and 2b with the 2024 ACC/AHA guidelines (P = 0.101), and the event rate was even reversed with the 2023 ESC guidelines (P = 0.545).

CONCLUSIONS

Among HCM phenotypes, the prognosis of patients with end-stage HCM was markedly worse. The 2024 ACC/AHA and 2023 ESC guidelines well stratified SCD risk in patients with HCM; the 2024 ACC/AHA guidelines seemed to better stratify SCD risk between Classes 2a and 2b compared with the 2023 ESC guidelines.