Patients With Undetermined Stroke Have Increased Atrial Fibrosis: A Cardiac Magnetic Resonance Imaging Study.

BACKGROUND AND PURPOSE: Some patients with ischemic strokes that are currently classified as having an undetermined cause may have structural or functional changes of the left atrium (LA) and left atrial appendage, which increase their risk of thromboembolism. We compared the LA and left atrial appendage of patients with different ischemic stroke causes using cardiac magnetic resonance imaging. METHODS: We prospectively included a consecutive sample of ischemic stroke patients. Patients with structural changes on echocardiography currently considered as causal for stroke in the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification were excluded. A 3-T cardiac magnetic resonance imaging was performed. RESULTS: One hundred and eleven patients were evaluated. Patients with an undetermined cause had a higher percentage of LA fibrosis (P=0.03) than patients with other stroke causes and lower, although not statistically significant, values of LA ejection fraction. Patients with atrial fibrillation and undetermined stroke cause showed a similar value of atrial fibrosis. CONCLUSIONS: The LA phenotype that was found in patients with undetermined cause supports the hypothesis that an atrial disease may be associated with stroke.