Hidden Heart Dysfunction Triples Stroke Risk in Cardiac Patients

New research presented at the American Heart Association's Scientific Sessions 2025 reveals a hidden heart dysfunction that significantly increases stroke risk in people with transthyretin amyloid cardiomyopathy (ATTR-CM), a progressive condition where protein buildup stiffens heart walls. The study from the U.K. National Amyloidosis Centre analyzed health records of over 2,300 adults with ATTR-CM and discovered that approximately 1 in 8 patients with regular heart rhythm had atrial electromechanical dissociation (AEMD), a condition where the upper heart chamber appears normal on electrocardiograms but doesn't contract effectively. During nearly three years of follow-up, researchers found these individuals were more than three times as likely to experience strokes or transient ischemic attacks compared to those with normal atrial contraction.

The research team, led by Dr. Aldostefano Porcari from the University of Trieste and University College London, developed a noninvasive risk assessment tool using widely available echocardiogram measures to identify patients at highest stroke risk. The tool revealed that stroke risk rose steadily as the atrium's ability to squeeze weakened, with the highest-risk group experiencing approximately 9 strokes per 100 people annually. This risk pattern remained consistent across different genetic subtypes of ATTR amyloidosis and various disease stages, suggesting atrial dysfunction represents a common driver of stroke risk in this condition. The findings shift attention from heart rhythm function to mechanical performance, potentially guiding earlier conversations about preventive strategies including anticoagulation medications.

While the study offers promising insights, researchers acknowledge limitations including its observational nature and the specialized imaging technique required for AEMD diagnosis. The next step involves conducting prospective, multicenter studies to validate the tool and investigate whether preventive anticoagulation can effectively reduce stroke risk in this population. As Dr. Fernando Testai, vice-chair of the American Heart Association's Brain Health Committee noted, this research addresses a critical gap in identifying high-risk individuals who may benefit from anticoagulation even without atrial fibrillation, potentially preventing disabling or fatal cerebrovascular events in a population that faces significantly elevated stroke risk compared to the general population.