The heart acts like a pump, pumping blood throughout the body with each beat, providing oxygen and nutrients to the tissues and organs of the body. This mechanical activity of the heart is controlled and governed by electrical activity, which normally originates from the sinus node located in the atria, which regularly sends electrical impulses, 60-100 times per minute, to all parts of the heart, causing sequential and regular contractions in all parts of the heart (atria to ventricles). In atrial fibrillation, the electrical activity of the heart is no longer governed by the sinoatrial node and is replaced by rapid, disorganized electrical activity in the atria, with correspondingly rapid and irregular contractions and diastole in the ventricles. In atrial fibrillation, cardiac output is reduced by more than a quarter or even 50%, especially in the presence of impaired ventricular function. Atrial fibrillation can induce or aggravate heart failure and pulmonary edema and induce myocardial ischemia. The loss of atrial contractility can lead to intra-atrial thrombus formation, which can be dislodged and cause cerebral or other peripheral vascular embolism. Atrial fibrillation is an independent risk factor for stroke. The average annual incidence of ischemic stroke in patients with atrial fibrillation is 5%, accounting for 10%-15% of cerebral infarction; the risk of cerebral embolism in patients with non-valvular atrial fibrillation is 5-7 times higher than that without atrial fibrillation, and when the heart has valvular disease (such as rheumatic heart disease), the incidence ratio is even higher. The annual risk of cerebral thromboembolism in patients with atrial fibrillation is about 5%, and thrombosis due to atrial fibrillation accounts for 10%-15% of cerebral infarction, and stroke after atrial fibrillation has a higher mortality and disability rate. A retrospective study showed that 71% of cerebral emboli died or left with severe neurological symptoms within 6 weeks of observation. In prospective studies of both sexes, 63% and 44% of stroke patients with atrial fibrillation died or were disabled, respectively.