Predictors of new onset atrial fibrillation during 10-year follow-up after first-ever ischemic stroke.

Background: Paroxysmal atrial fibrillation (AF) may be underdiagnosed in ischemic stroke patients but may be pivotal for initiation of oral anticoagulation therapy. We assessed clinical and ECG predictors of new-onset AF during 10-year follow-up (FU) in ischemic stroke patients.

Methods: The study sample comprised of 227 first-ever ischemic stroke patients without AF (median age 73, interquartile range 25%-75% 63-80years, 92 female) and 1:1 age- and gender-matched controls without stroke and AF enrolled in the Lund Stroke Register from March 2001 to February 2002. New-onset AF during FU was assessed by screening through regional ECG database and by record linkage with Swedish National Patient Register. The standard 12-lead sinus rhythm ECGs at stroke admission were retrieved from electronic database and digitally processed. Clinical baseline characteristics were studied using medical records.

Results: During FU, AF was found in 39 stroke patients and 30 controls, p=0.296. In stroke patients in multivariate Cox regression analysis AF was associated with hypertension (HR 3.45 CI 95% 1.40-3.49, p=0.007) and QRS duration (HR 1.02 CI 95% 1.00-1.03, p=0.049). High cardiovascular risk was predictive for AF development: for CHADS2≥4 HR 2.46 CI 95% 1.45-4.18, p=0.001 and for CHA2DS2-VASc≥5 HR 2.29 CI 95% 1.43-3.68, p=0.001. New onset AF was not associated with baseline ischemic stroke: HR 1.46 95% CI 0.90-2.35, p=0.121.

Conclusion: High CHADS2 and CHA2DS2-VASc scores, but not baseline ischemic stroke, predict new onset AF in FU. QRS duration might be considered a potential risk marker for prediction of AF after ischemic stroke.