Limitations in the methods used to diagnose atrial fibrillation -- periods of irregular heartbeat -- in population-based studies might explain why findings indicate that atrial fibrillation is less common among blacks than whites, according to a study published in the journal Stroke, Reuters Health reports. Atrial fibrillation is a major predictor of stroke, in which blacks have a higher rate than whites, but the reported low prevalence of atrial fibrillation among blacks has perplexed researchers.

To further investigate, Elsayed Soliman of Wake Forest University School of Medicine and colleagues used an approach called ECG, which is a diagnostic tool that measures the electrical signals of the heart, in 15,429 study participants. Twenty-seven percent of the participants were black. When examining the ethnic distribution of ECG predictors of atrial fibrillation, researchers confirmed that atrial fibrillation was significantly less common among blacks than whites -- 0.24% compared with 0.95%. However, blacks had significantly higher and more abnormal values for the atrial fibrillation predictors, and atrial fibrillation was intermittent and more difficult to identify in blacks.

Soliman said that "not seeing atrial fibrillation in a black patient's ECG does not mean that he or she is not at risk or already having intermittent episodes of atrial fibrillation," adding, "Physicians should use the ECG to evaluate black patients' risk of stroke by determining if the patient has certain predictors of atrial fibrillation, instead of the condition itself." He added, "This will enable physicians to know who is at risk for stroke and subsequently can take the appropriate preventive measures" (Rauscher, Reuters Health, 5/11).


An abstract of the study is available online.