Differences in left atrial structure and pathophysiology between Black and white ischemic stroke patients may help explain racial disparities in stroke risk, a U.S. study suggests.

Researchers examined data on 3,426 ischemic stroke patients who were participants in the Greater Cincinnati/Northern Kentucky Stroke study and had no history of atrial fibrillation or flutter.

The mean left atrial diameter measurement was 3.65cm, with a smaller mean diameter for Black patients (3.58 cm) than for white patients (3.69 cm), based on an analysis of data for 2,391 participants.

When researchers analyzed P-wave terminal force in ECG lead V1 (PTFV1) in a subset of 3,209 participants, they found the overall mean PTFV1 measurement was 3,434 mV*ms. Black race was associated with higher measurements (adjusted beta coefficient 1.45), with a mean in Black patients of 3,183 mV*ms versus 2,258 mV*ms in white patients, according to the report published in Neurology.

“We are not sure about the reasons for the different profiles of atrial disease seen in Black patients versus white patients, and it will be important for future research to focus on that.” said lead study author Dr. Hooman Kamel, vice chair for research in the Department of Neurology at Weill Cornell Medicine in New York City.

“But, because clinicians currently focus on just one aspect of atrial disease when predicting stroke risk, our study suggests that these different profiles across racial groups means that we need more racially inclusive diagnostic markers,” Dr. Kamel said by email.

It’s not clear from the current study whether the differences between Black and white patients might be explained by specific genetic traits or environmental circumstances, Dr. Kamel said.

“Presumably a lot or all of it may be environmental,” Dr. Kamel added. “We think the disparity in stroke risk between Black individuals and white individuals might be modifiable in part by coming up with better, more racially inclusive diagnostic standards for atrial disease.”

A limitation of the study was the lack of socioeconomic information on the participants, including data on education, exposure to social and economic stressors, and perceived racism.

“Currently, we use atrial fibrillation to denote potential atrial thromboembolism, and call other suspected cardioembolic strokes without defined atrial arrhythmia cryptogenic,” said Dr. Sarah Song, an associate professor in the department of neurological sciences at Rush University Medical Center in Chicago, Illinois.

This definition of cardioembolic stroke will likely continue to evolve to include thrombogenic atrial cardiopathy, Dr. Song, who wasn’t involved in the study, said by email.