Atrial Fibrillation Is Associated With a Worse 90-Day Outcome Than Other Cardioembolic Stroke Subtypes

Background and Purpose-Patients with a cardioembolic stroke (CES) have worse outcomes than stroke patients with other causes of stroke. Among patients with CES, atrial fibrillation (AF) is a common comorbidity. Mounting data indicate that AF may be related to stroke pathogenesis beyond acute cerebral thromboembolism. We sought to determine whether AF represents an independent risk factor for stroke severity and outcome among patients with CES. Methods-We retrospectively analyzed patients with acute hemispheric CES included in an academic medical center's stroke registry. CES was determined using the Causative Classification System of ischemic stroke. Multivariable logistic regression was used to determine whether AF was associated with 90-day outcome functional status. Results-Our cohort included 140 patients. Of these, 52 had prevalent AF and 28 had incident AF diagnosed during their index hospitalization or within 90 days of hospital discharge. After adjustment for potential confounders or mediators, any AF (odds ratio, 2.51; 95% confidence interval, 1.03-6.33; P=0.049), infarct volume (odds ratio, 1.03; 95% confidence interval, 1.01-1.06; P=0.005), preadmission modified Rankin Scale score (odds ratio, 2.58; 95% confidence interval, 1.66-4.01; P<0.001), and admission National Institutes of Health Stroke Scale score (odds ratio, 1.17; 95% confidence interval, 1.08-1.28; P<0.001) remained associated with an unfavorable 90-day outcome (modified Rankin Scale score, 2-6). Conclusions-AF is associated with an unfavorable 90-day outcome among patients with a CES independent of established risk factors and initial stroke severity. This suggests that AF-specific mechanisms affect CES severity and functional status after CES. If confirmed in future studies, further investigation into the underlying pathophysiological mechanisms may provide novel avenues to AF detection and treatment.