The main risks of atrial fibrillation are stroke and heart failure. In atrial fibrillation, the mechanical contraction of the atria is lost, and blood stagnation can easily form thrombus. If the thrombus is dislodged, the embolus can be circulated throughout the body, causing cerebral infarction or embolism of the body circulation and leading to disability and death. The incidence of thromboembolic events in patients with atrial fibrillation is 5 to 17 times higher than that in normal subjects. The annual stroke rate in non-valvular atrial fibrillation patients without anticoagulation is 5.3%, and 35% of patients have had at least one stroke in their lifetime. Old age, hypertension, diabetes mellitus, coronary artery disease, and a history of chronic heart failure are all risk factors for stroke in atrial fibrillation. Therefore, anticoagulation is necessary for patients with atrial fibrillation who are at high risk for stroke. Second, loss of effective atrial systolic function and prolonged tachycardia in patients with atrial fibrillation can lead to tachycardia cardiomyopathy, which eventually leads to decreased cardiac function and even heart failure.