Nonvalvular atrial fibrillation and stroke

Cardioembolism, responsible for approximately one-third of cerebral infarctions in Japan, causes serious cerebral infarction with poor prognosis. Nonvalvular atrial fibrillation (NVAF) is the most important cause of cardioembolism. Both the occurrence of NVAF and the frequency of its progression to cerebral infarction increase with age. Timely introduction of warfarin depending on the presence or absence of risk factors for cerebral infarction, including age, is essential for the prevention of cardioembolism. At present, monitoring based on PT-INR is indispensable for warfarin therapy. Oral direct thrombin inhibitors seem promising as a future therapy achieving a stable anticoagulation effect by the use of a fixed dose. Angiotensin II receptor blockers (ARBs) are expected to be effective in preventing new atrial fibrillation and maintaining sinus rhythm, offering a promise of clinical usefulness in reducing cerebral infarction, including the prevention of relapse.