Heart Scans Reveal Structure May Impact Racial and Ethnic Stroke Risk Disparities

November 25, 2020
Whitney J. Palmer

Left atrial diameter and fibrosis differences between African American and white patients could play a role the risk of ischemic stroke.

The structure of the heart can make a difference in how stroke symptoms present in both African American and white patients, a new study has found. These results point to a need for updated diagnostic standards, investigators said.

In a study published in the Nov. 25 Neurology®, researchers from Weill Cornell Medicine outlined differences in the left atrium of the heart that could play a role in a patient’s risk of stroke.

“Our findings should not be taken to imply that these racial differences in people with stroke reflect innate biological differences,” said study author Hooman Kamel, M.D., director of the Weill Cornell Medicine Clinical and Translational Neuroscience Unit t the Brain and Mind Research Institute. “Our findings suggest that the current standards for diagnosing left atrial disease that can lead to stroke may need to be updated. These standards were established in groups of exclusively white people and may not fully reflect the variety and complexity of how these acquired cardiac issues are manifested in all people.”

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Overall, African Americans in the United States do have a higher risk of ischemic stroke than their white counterparts, but known risk factors do not completely explain these differences. If providers could get a better understanding of the potential underlying causes of these strokes, they could possible do a better job in addressing these racial disparities, he said.

To delve deeper into this question, Kamel’s team enrolled 2,391 African American and white ischemic stroke patients into a study and examined electrocardiograms (ECG) and echocardiograms that focused on the structure and function of the heart’s left atrium. Using those tests, they measured the left atrium diameter and analyzed the amount of fibrosis and other abnormalities in the left atrium that have been associated with stroke.

Based on their evaluations, they determined the average diameter of the left atrium in study participants was 3.65 cm – 3.59 cm for African Americans and 3.69 for white patients. However, even after the team adjusted for age, body mass index, and other chronic conditions, such as high blood pressure, African American patients exhibited more markers for left atrial fibrosis on ECG.

“These findings reveal systematic differences in left atrium between [African American] versus white patients with ischemic stroke,” he said, “so clinicians should be aware that structural or functional changes in the left atrium may not present similarly in all stroke populations.”

Even though these tests and images support the need for updated diagnostic standards, Kamel said, further research is still needed on whether a better understanding around the many ways cardiac disease can manifest and clot-reducing drugs can reduce racial and ethnic disparities around stroke.