Racial differences in the prevalence of cardiac sources of embolism in subjects with unexplained stroke or transient ischemic attack evaluated by transesophageal echocardiography

Little is known about the distribution of cardiac sources of embolism among African-Americans with cryptogenic cerebrovascular events. We compared the prevalence of potential cardiac sources of embolism between black and white patients referred to our laboratory for transesophageal echocardiographic (TEE) evaluation of unexplained stroke or transient ischemic attack. Records were reviewed to exclude subjects with high-risk cardiac or vascular disorders likely to explain the index event. Of 297 patients satisfying the inclusion criteria, 196 were white and 87 black. Potential cardioembolic sources were significantly less common in blacks than in whites (adjusted odds ratio [OR], 0.44; 95% confidence interval [CI] 0.26 to 0.75), and related largely to the difference in prevalence of interatrial communication (OR 0.40; 95% CI 0.21 to 0.74). In contrast, African-Americans had a higher prevalence of left ventricular (LV) hypertrophy (OR 3.50; 95% CI 1.97 to 6.22), and particularly, moderate or severe hypertrophy (OR 4.03; 95% CI 1.88 to 9.65) compared with whites. In conclusion, in African-Americans with unexplained cerebrovascular events, the yield of TEE for potential cardioembolic sources, and especially interatrial communication, is lower than in their white counterparts. African-Americans exhibit a substantially higher prevalence of LV hypertrophy, which may be a marker for a higher burden of subclinical cerebrovascular disease involved in the pathogenesis of cryptogenic cerebral ischemia in this population.