Racial and ethnic differences in subclinical myocardial function: the Multi-Ethnic Study of Atherosclerosis

Background Racial/ethnic differences in the incidence and severity of heart failure (HF) are not well understood, but may be related to pre-existing variations in myocardial function. Objective To examine racial/ethnic differences in regional myocardial function among asymptomatic individuals free of known cardiovascular disease. Design, setting and patients The Multi-Ethnic Study of Atherosclerosis is a prospective, observational study of individuals without baseline cardiovascular disease, representing four major racial/ethnic groups. A total of 1099 study participants underwent cardiac MRI with tissue tagging; for each study, peak systolic strain (Ecc) and strain rate (SRs) were determined in four left ventricular (LV) regions. Main outcome measures Multiple linear regression was used to analyse the relationship between race/ethnicity and regional strain (Ecc and SRs) while adjusting for cardiovascular risk factors. Results Compared with other racial/ethnic groups, Chinese-Americans had the greatest magnitude of Ecc in a majority of LV regions (-19.60 +/- 3.78, p<0.05); Chinese-Americans also had the greatest absolute values for SRs in all regions, reflecting higher rate of systolic contraction (-2.01 +/- 0.76, p<0.05). Conversely, African-Americans had the lowest Ecc values (-17.50 +/- 4.00, p<0.05) in the majority of wall regions while Hispanics demonstrated the lowest rate of contractility in all wall regions (-1.44 +/- 0.50, p <= 0.001) in comparison with the other racial/ethnic groups. These race-based differences remained significant in the majority of LV wall regions after adjusting for multiple variables, including hypertension and LV mass. Conclusions Important race-based differences in regional LV systolic function in a large cohort of asymptomatic individuals have been demonstrated. Further research is needed to investigate the possible mechanisms related to the race/ethnicity-based variations found in this study.