Clinically silent atrial septal defects with evidence for cerebral embolization.

The cause of stroke in young patients frequently cannot be established. Eleven consecutive patients, age 50 and younger, had clinical evidence of cerebral embolization. Results of physical, radiographic, electrocardiographic, and two-dimensional echocardiographic examinations were normal in all patients. During normal respiration, eight of the patients had right-to-left shunts at the atrial level shown by microcavitation contrast two-dimensional echocardiography. Six of the eight patients with positive contrast studies had cardiac catheterization. Five of six patients had an atrial septal defect, normal right and left heart pressures, and small right-to-left shunts during a Valsalva strain. Four patients had surgical closure of the defect, which ranged in size from 5 to 10 mm. The remaining patients received anticoagulants. Interatrial communications appear to be common in young patients with stroke, suggesting paradoxical embolization as a possible mechanism. Contrast two-dimensional echocardiography should be done in such patients because it is the only noninvasive technique that reliably finds these defects.