Exercise-induced quantitative microvolt T-wave alternans in hypertrophic cardiomyopathy.

•Hypertrophic cardiomyopathy is the leading cause of SCD in young adults and athletes.•Patients were stratified as high-risk and low-risk groups per Maron score risk factors.•High levels of microvolt T-wave alternans identified high-risk patients.•Higher TWA values were associated with isolated major risk factors for SCD.