Abstract 13502: African Americans with Hypertrophic Cardiomyopathy Manifest a More Myopathic and Less Obstructive Phenotype than Caucasians
Background: Hypertrophic Cardiomyopathy (HCM) is an inherited cardiomyopathy known to affect African Americans who may be proportionately at higher risk than other ethnic groups. However, there has been no systematic study of possible racial differences in clinical and phenotypic manifestations of HCM.
Results: We examined 206 HCM patients in the Johns Hopkins HCM clinic, 60 with African American and 146 with Caucasian ancestry. All underwent clinical examination and detailed echocardiography including measurement of left ventricular morphology and outflow tract (LVOT) gradients at rest and with provocation, and speckle-tracking based deformation analysis using GE EchoPac version 7.1.1. Both groups were comparable with regards to age, NYHA class, gender, septal thickness and diastolic function (table 1). However, African American patients had significantly lower exercise capacity (8.7±3.8 vs.10.3±4.0, P=0.02). Both resting and all provoked LVOT gradients were significantly lower in African Americans. Global systolic strain was significantly impaired indicating more pronounced myopathy and abnormal systolic mechanics in the setting of normal ejection fraction. All differences remained significant after adjusting for relevant confounders (table 2).
Conclusion: Our data suggest significant racial differences in the manifestation of HCM. Compared to Caucasians, African American patients present with significantly lower exercise capacity in the setting of similar hypertrophy, lower LVOT gradients and similar diastolic dysfunction. Impaired systolic strain in African Americans indicates a more pronounced myopathic process.
- © 2012 by American Heart Association, Inc.