Early and long-term risk of new-onset atrial fibrillation after transient ischemic attack

Background: Transient ischemic attack (TIA) provides a unique opportunity to optimize secondary preventive treatments to avoid subsequent ischemic stroke (IS). Although atrial fibrillation (AF) is the leading cause of cardioembolism in IS and anticoagulation prevents stroke recurrence (SR), limited data exists about the risk of new-onset AF after TIA. Methods: We carried out a prospective cohort study of consecutive patients with TIA from January 2006 to June 2010. The risk of new diagnosis of AF and SR was defined after a median follow-up time of 6.5 (5.0-9.6) years. In a subgroup of consecutive patients, a panel of biomarkers was assessed during the first 24 h of the onset of symptoms. Results: 723 TIA patients were included. New-onset AF was diagnosed in 116 (16.0%) patients, 42 (36.2%) of them during admission. 204 (28.2%) patients were included in the biomarker substudy. New-onset AF was associated with sex (female) (hazard ratio [HR] 1.61 [95% CI, 1.07- 2.41]), age (HR 1.05 [95% CI, 1.03-1.07]), previous ischemic heart disease (HR 1.84 [95% CI 1.15-2.97]) and cortical DWI pattern (HR 2.81 [95% CI 1.87-4.21]). In the Kaplan-Meier analysis, NT-proBNP [≥]218.2 pg/ml (log-rank test P<0.001) was associated with significant risk of new-onset AF during the first five years of follow-up. Patients with a new diagnosis of AF after admission and before five years of follow-up had the highest risk of SR (P=0.002). Conclusion: The risk of new diagnosis of AF after TIA is clinically relevant. We identified clinical, neuroimaging and biomarker predictors of new-onset AF.