The ACTIVE W trial showed that, like persistent AF, paroxysmal AF has a similar risk of stroke and non-central nervous system embolism. Anticoagulation is superior to aspirin plus clobigrel therapy for both paroxysmal and persistent AF. The guidelines for AF state that patients at risk of stroke should take oral anticoagulants in both paroxysmal and persistent AF, but the evidence for this view is not strong for patients with paroxysmal AF. Therefore, an analysis of the ACTIVE W study with 6706 patients clearly showed a significant advantage of warfarin over aspirin plus clobigine in reducing stroke, thrombosis, infarction, and vascular death, with the greatest benefit especially in stroke prevention. In contrast, there was no significant difference between the two groups in terms of the side effects of major bleeding. Another question is whether the risk of stroke is the same in paroxysmal AF as in persistent AF and whether warfarin or aspirin/clopidogrel is equally efficient and safe in paroxysmal and persistent AF. Indeed, patients with paroxysmal AF are at low risk: younger, shorter history of AF, relatively little valvular disease, relatively little history of heart failure and diabetes mellitus, but have a greater incidence of hypertension, have the same complications of thromboembolism as continuous AF, and should be taken as seriously as continuous AF. The main explanation for the higher thromboembolic complications in the former than in the latter in the AFFIRM trial is because the former was not treated with anticoagulation in paroxysmal atrial fibrillation, which is predominantly rhythmically controlled, and in persistent atrial fibrillation, which is predominantly ventricular rate controlled. We would like to emphasize that if you have AF with at least one risk factor (heart failure, hypertension, age, diabetes, history of stroke or history of transient ischemic attack), either paroxysmal or persistent AF should be treated with warfarin. The extent to which paroxysmal AF (number, duration) can cause the same thromboembolic complications as persistent AF is inconclusive and awaits the publication of the ASSERT trial results.