THURSDAY, Sept. 9 , 2010 (HealthDay News) -- Mexican-American stroke survivors with a heart rhythm disorder called atrial fibrillation are more than twice as likely to suffer a second stroke compared to white patients, a new study finds.
It also found that even though these strokes are more likely to be severe among Mexican-Americans, they don't have a greater risk of death after a second stroke.
In people with atrial fibrillation, the heart's upper chambers (atria) beat irregularly and don't pump blood effectively. This can cause blood to pool within the atria, which can lead to the formation of blood clots that can break off and travel to the brain, causing a stroke.
This study included 88 Mexican-Americans and 148 white stroke survivors with atrial fibrillation. Compared to the white patients, the Mexican-American stroke survivors were younger, less likely to have completed 12 years of education, more likely to have diabetes, and less likely to have a primary care physician.
Over a median follow-up of 427.5 days, 19 Mexican-Americans and 14 whites had at least one recurrent stroke. All but one of those cases involved an ischemic stroke, which is caused by blocked blood flow to the brain. One Mexican-American patient suffered a hemorrhagic stroke, which is bleeding in the brain.
The study appears in the current issue of the journal Stroke.
"Based on some of our prior research, we were not necessarily surprised by the higher recurrence rate in Mexican-Americans with atrial fibrillation, but the greater severity of recurrent strokes in Mexican-Americans was surprising," co-author Dr. Darin B. Zahuranec, an assistant professor of neurology at the University of Michigan Cardiovascular Research Center in Ann Arbor, said in an American Heart Association news release.
One reason for the difference in stroke rates could be that Mexican-Americans may not have managed the blood-thinning drug warfarin -- often used to prevent stroke -- in the most optimal way, Zahuranec said. He and his colleagues did not evaluate outpatient use of warfarin, which might have contributed to the increased risk of stroke in Mexican-Americans.
The American Academy of Family Physicians has more about atrial fibrillation.