Clinical Course and Significance of Hypertrophic Cardiomyopathy Without Left Ventricular Hypertrophy

Increased availability of genetic testing for hypertrophic cardiomyopathy (HCM) has led to emergence of a novel patient subset within the heterogeneous disease spectrum, consisting of asymptomatic genetically affected family members with normal cardiac function without left ventricular hypertrophy (LVH) (1). These genotype-positive (+) - LVH-negative (-) (G+LVH-) individuals raise unresolved clinical issues concerning conversion to HCM phenotypes and risk for cardiovascular complications (2,3). Given the presumed thousands of gene carriers among HCM families, we have assessed here the clinical profiles and outcome of G+LVH- individuals in a large international multicenter cohort.