A prospective assessment of myocardial contractility in young African Americans: does ethnicity impact the wall stress-heart rate-corrected velocity of circumferential fiber shortening relationship?

摘要

BACKGROUND: The end-systolic wall stress (ESS)-heart rate-corrected velocity of circumferential fiber shortening (VCFc) relationship provides a load-independent assessment of systolic function. Previously published indices may not be appropriate for studies where ethnicity may introduce bias. OBJECTIVE: We sought to investigate potential differences in the ESS-VCFc relationship between the African American (AA) and Caucasian population. METHODS: In all, 50 AAs and 72 Caucasians, age 3 months to 17 years, were studied. Arterial pulse tracing, phonocardiogram, electrocardiogram, and M-mode of the left ventricle were recorded. Left ventricular dimensions, functional indices, ESS, and ESS-VCFc relationships were compared between groups. RESULTS: AAs had decreased indexed left ventricular end-systolic dimensions and increased septal and posterior wall thickness. AAs had increased percent fractional shortening, VCFc, and decreased ESS. Meridional ESS-VCFc relationships for the groups were similar. CONCLUSIONS: Young AAs have slightly thicker ventricles with increased VCFc, lower systolic volumes, and diminished ESS compared with control subjects. Despite differences, the meridional ESS-VCFc relationships were similar and correlated closely to previously reported normal indices.