Relationship of Preexisting Cardiovascular Comorbidities to Newly Diagnosed Atrial Fibrillation After Ischemic Stroke

Background and Purpose-There remains uncertainty as whether newly diagnosed atrial fibrillation (AF) after ischemic stroke reflects underlying heart disease and represents an increased risk of cardioembolic stroke, or whether it is triggered by neurogenic mechanisms. We aimed to determine whether cardiovascular comorbidities in patients with new AF after ischemic stroke differ from patients with previous known AF or without AF. Methods-This French longitudinal cohort study was based on the database covering hospital care from 2009 to 2012 for the entire population. Results-Of 336 291 patients with ischemic stroke, 240 459 (71.5%) had no AF and 95 832 (28.5%) had previously known AF at baseline. Patients without previous AF had a mean CHA(2)DS(2)-VASc score of 4.98 +/- 1.63 SD. During a mean follow-up of 7.9 +/- 11.5 months, 14 095 (5.9%) of these patients had incident AF, representing an annual incidence of AF after ischemic stroke of 8.9 per 100 person-years (95% confidence interval, 8.8-9.0). New AF patients had higher CHA(2)DS(2)-VASc score, more likely comorbidities, and more frequent history of previous transient ischemic attack than patients with previous known AF or without AF. Conclusions-Preexisting cardiovascular comorbidities underlie AF newly diagnosed after stroke. Consequently, these high-risk patients should be closely monitored for incident AF to facilitate an earlier diagnosis of AF and avoid stroke with appropriate thromboprophylaxis.