Pathogenesis of anterior circulation stroke in patients with nonvalvular atrial fibrillation

We studied coexisting potential arterial and cardiac causes of stroke in 159 patients with nonvalvular atrial fibrillation (AF), who were admitted to a population-based primary care center for an anterior circulation infarct. Systematic investigations included brain CT, carotid Doppler ultrasounds with frequency analysis and echotomography, and mono- and bidimensional echocardiography. Lacunar infarction due to small-artery disease was at least as likely as an AF-related stroke in 13% of the patients who had hypertension and a small deep infarct. In 67% of the patients, internal carotid artery disease ipsilateral to infarct was present, but it was severe (greater than or equal to 50% stenosis or occlusion) in only 11%. There was a potential cardiac source of embolism other than AF in 14%. Overall, although only 18% of the patients had AF as the only potential cause of stroke, embolism from the heart remained the most likely etiology of infarct in 76%. Our findings emphasize the role of AF-related hemodynamic disturbances, which were often associated with embolic phenomena, and a rather low early risk of recurring embolism (4%) within the 1st month after stroke.