Background: The treatment of patients with recent onset atrial fibrillation (AF) often aims for rapid restoration of sinus rhythm. Current guidelines suggest that cardioversion can be performed safely without anticoagulation within 48 hours from symptoms onset. However, an unacceptable high risk of thromboembolism has been identified in patients with heart failure and diabetes, i.e. risk factors for stroke. Aim: To investigate the risk of thromboembolism after acute cardioversion versus rate control among patient with recent onset symptomatic atrial fibrillation. Methods: In this prospective study, patients presenting with resent onset atrial fibrillation will be screened for eligibility. Hypothesis: Among patients with risk factors for stroke, a rate control strategy significantly reduces the risk of thromboembolism.