Background: Atrial fibrillation (AF) is the most common arrhythmia and a common cause of ischemic stroke. Stroke patients with AF have been shown to have a poorer neurological outcome than stroke patients without AF.

Objectives: To determine the impact of pre-existing AF on residual degree of disability in patients treated with IV thrombolysis.

Methods: In this case-control study, data of 214 stroke patients (63 with AF and 151 without AF) were collected from the National Acute Stroke Israeli Registry, a nationwide quadrennial stroke database. Stroke severity and outcome were compared using the National Institute of Health Stroke Scale (NIHSS) on admission and the modified Rankin Scale (mRS) on admission and discharge. Demographics and stroke characteristics were also compared between the groups.

Results: Stroke severity, as determined by NIHSS at admission, was higher in the AF group than the non-AF. In the group of patients who were treated with intravenous tissue plasminogen activator (tPA), more patients had favorable outcomes (mRS = 0–1 on discharge) in the non-AF group than in the AF group (P = 0.058, odds ratio = 2.217, confidence interval 0.973 to 5.05).

Conclusions: Our study suggests worse outcome in thrombolized patients with AF compared to non-AF stroke patients. Therefore, AF itself can be a poor prognostic factor for tPA sensitivity regarding the chance of revascularization and recovery after intravenous tPA.