The annual sudden cardiac death rate in hypertrophic cardiomyopathy is less than 1%, though specific subgroups face a clearly higher risk.
first paragraph of articleSudden cardiac death (SCD) is a devastating and often unpredictable complication of hypertrophic cardiomyopathy (HCM) that may occur as the initial disease presentation, frequently in asymptomatic or mildly symptomatic young people. Until 2000, only small series of patients examining predictors of SCD had been published, with a selection bias towards severe disease. Subsequently, larger series that are more representative of the HCM spectrum have shown that the annual SCD rate is less than 1%, and that there are subgroups of patients with a clearly higher risk.
Jordà et al. (2018) studied this question.