Atrial Dysfunction Assessment May Help Predict Stroke Risk in Heart Condition Patients

People with transthyretin amyloid cardiomyopathy who also have a mechanical malfunction in the atrial chamber of their heart face significantly higher stroke risk, according to research to be presented at the American Heart Association's Scientific Sessions 2025. The study found that atrial electromechanical dissociation, where the atrium appears normal on electrocardiogram but doesn't contract effectively, more than tripled stroke risk in patients with this progressive condition that stiffens heart muscle.

Researchers at the U.K. National Amyloidosis Centre analyzed health records of more than 2,300 adults with transthyretin amyloid cardiomyopathy between 2003 and 2023. Approximately one in eight patients with regular heart rhythm had this hidden atrial dysfunction. During nearly three years of follow-up, those with poor atrial contraction were over three times more likely to experience stroke or transient ischemic attack compared to those with normal atrial function. These patients were also more likely to develop atrial fibrillation during follow-up.

The study developed a risk-prediction tool using two echocardiogram measures to assess mechanical function of the atrial chamber. Stroke risk increased steadily as the atrium's squeezing ability weakened, with the highest-risk group experiencing about nine strokes per 100 people annually. The risk pattern remained consistent across different genetic subtypes of ATTR amyloidosis and disease stages, suggesting atrial dysfunction represents a common driver of stroke risk in this condition.

"Even with a regular heart rhythm, some people with transthyretin amyloid cardiomyopathy are still at risk of stroke if their atrium doesn't squeeze well," said study author Aldostefano Porcari, M.D., Ph.D., consultant cardiologist at Cardiovascular Department, University of Trieste, Italy. "Our study indicates that atrial contraction may matter as much as heart rhythm in predicting risk."

Fernando D. Testai, M.D., Ph.D., FAHA, vice-chair of the American Heart Association's Brain Health Committee, noted that "patients with amyloid cardiomyopathy who remain in sinus rhythm still exhibit a significantly elevated stroke risk compared to the general population, so there is a need for novel strategies to identify high-risk individuals who may benefit from anticoagulation, even in the absence of atrial fibrillation." Additional information about the American Heart Association's research and initiatives can be found at https://www.heart.org.

The study's findings could help guide earlier conversations about preventive strategies including anticoagulation medications. However, researchers acknowledge limitations including the specialized imaging technique required for diagnosis and the need for validation in larger, independent groups. The next step involves conducting a prospective, multicenter study to investigate how this tool works and whether preventive anticoagulation can lower stroke risk in people with atrial electromechanical dissociation.