ECHOCARDIOGRAPHIC PREDICTORS OF STROKE IN PATIENTS WITH ATRIAL-FIBRILLATION - A PROSPECTIVE-STUDY OF 1066 PATIENTS FROM 3 CLINICAL-TRIALS

Background: Clinical features that consistently predict ischemic strok e in patients with nonvalvular atrial fibrillation have been identifie d, while echocardiographic risk factors are less well defined. Objecti ve: To determine whether the results of transthoracic echocardiography add independent information to the clinical risk factors for stroke i n patients with atrial fibrillation. Methods: Transthoracic echocardio graphic findings and clinical features from 1066 patients with atrial fibrillation assigned to placebo or control in 3 randomized trials (Bo ston Area Anticoagulation Trial for Atrial Fibrillation, Stroke Preven tion in Atrial Fibrillation I Study, and Veterans Affairs Prevention i n Atrial. Fibrillation Study) were correlated with subsequent ischemic stroke by multivariate analysis. Results: The mean +/- SD age of pati ents was 67 +/- 10 years, 78% were men, 55% had a history of hypertens ion, 19% had a history of diabetes, 7% had a previous transient ischem ic attack or stroke, and 27% had a history of heart failure. During a mean follow-up of 1.6 years, 78 ischemic strokes occurred (annual rate , 4.7%). Moderate to severe left ventricular systolic dysfunction show n via 2-dimensional echocardiography was a strong independent predicto r of stroke (relative risk, 2.5; P<.001) in the 1010 patients in whom echocardiographic values for left ventricular function were available. Left atrial diameter by M-mode echocardiography did not predict strok e (relative risk, 1.02/mm; P =.10). Of 163 patients categorized as low risk based on clinical features (annual stroke rate, 0.8%; 95% confid ence interval, 0.2%-3.0%), 10 had moderate to severe left ventricular dysfunction shown via 2-dimensional echocardiography and a 9.3% per ye ar risk of stroke (95% confidence interval, 1.3%-66%). Conversely, 728 of the 847 patients at high risk for stroke based on clinical criteri a had normal or mildly abnormal left ventricular function; their strok e rate was 4.4% (95% confidence interval, 3.4%-5.8%). Conclusions: Lef t ventricular systolic dysfunction shown via 2-dimensional transthorac ic echocardiography independently predicts risk of stroke in patients with atrial fibrillation. Echocardiography may prove most useful in a small group of patients who have a low risk of stroke according to cli nical factors.