Validation of the 2014 European Society of Cardiology Sudden Cardiac Death Risk Prediction Model Among Various Phenotypes in Japanese Patients With Hypertrophic Cardiomyopathy

Risk stratification for sudden cardiac death (SCD) is essential in the management of hypertrophic cardiomyopathy (HC). The 2014 European Society of Cardiology SCD risk prediction model (Risk-SCD) is a novel risk scoring system; however, whether it can be applied to Japanese HC and its usefulness among various HC phenotypes remain unclear. The aim of this study was to validate the Risk-SCD model in Japanese HC, and to evaluate its usefulness among various HC phenotypes. We studied 370 consecutive Japanese HC patients evaluated for primary SCD prevention at our tertiary referral center. The Risk-SCD model was validated in 289 HC patients with ejection fraction (EF) ≥50% (including left ventricular outflow tract obstruction [LVOTO], mid ventricular obstruction [MVO], apical hypertrophy, and nonobstructive phenotypes), and 81 end-stage HC patients (EF 6%) regardless of phenotypes; LVOTO, MVO, apical, and nonobstructive, but misclassified SCD risk in end-stage HC. In the current external validation of the Risk-SCD model in Japanese HC, the model improved SCD prediction compared with previous approaches, and was also shown to be useful in LVOTO, MVO, apical, and nonobstructive phenotypes.