Prevention of stroke due to atrial fibrillation Atrial fibrillation (AF) is a common cardiac arrhythmia, and the prevalence increases with age. There is 1 AF patient for every 25-100 people aged ≥60 years; 1 AF patient for every 10 people aged ≥80 years. China currently has about 5-10 million patients with atrial fibrillation. It is expected that in 2050, with the aging of the population, the total number of AF patients worldwide will increase at least 2.5 times compared to today, and AF has become the “epidemic” of the 21st century. Atrial fibrillation is not usually a direct cause of death. However, stroke is one of the major complications of atrial fibrillation and is an important cause of death and disability in patients with atrial fibrillation. 91% of atrial fibrillation embolisms are complications of cerebral embolism, and at least 15% to 20% of ischemic strokes are caused by atrial fibrillation. Stroke due to atrial fibrillation is characterized by high morbidity, disability and mortality. In recent years, research on atrial fibrillation and stroke prevention has made some remarkable progress. Paroxysmal atrial fibrillation is also associated with a high risk of stroke Previously, although paroxysmal atrial fibrillation had a high risk of cerebral embolism during the acute phase of the attack, it did not have a high risk of stroke during the remission phase. Recently, a growing number of studies have suggested that the risk of stroke in paroxysmal AF is as high as in persistent AF and permanent AF. The European Heart Survey data of 3890 AF cases showed that the incidence of ischemic stroke at 1 year follow-up after enrollment was similar in all groups of AF patients: 1.3% for first diagnosis of AF, 1.9% for paroxysmal AF, 1.2% for persistent AF, and 1.6% for permanent AF. The clopidogrel combined with irbesartan for prevention of vascular events in patients with atrial fibrillation also showed that the risk of stroke due to paroxysmal atrial fibrillation was similar to that of persistent atrial fibrillation and permanent atrial fibrillation. 2. Cryptogenic strokes may be caused mainly by paroxysmal atrial fibrillation The cause of approximately 20% to 40% of ischemic strokes cannot be determined. A study published in February 2009 in the American Journal of Neurology suggests that cryptogenic strokes may be caused primarily by paroxysmal atrial fibrillation. In this study, atrial fibrillation was monitored using a portable telecardiogram recorder (MCOT) in patients with cryptogenic stroke or cryptogenic transient ischemic attack (TIA) within 3 months of onset, and atrial fibrillation was detected in a total of 23% of patients during 21 days of monitoring, 85% of whom had atrial fibrillation of less than 30 seconds duration and 15% of whom had atrial fibrillation of 4 to 24 hours duration. The median time of first detection of atrial fibrillation was the 7th day after the start of monitoring. 3. Patients with asymptomatic cerebral infarction have a 2-fold increased risk of developing atrial fibrillation It is well established that patients with asymptomatic cerebral infarction are at least 5 times more likely than patients with symptomatic cerebral infarction, and patients with asymptomatic cerebral infarction have an approximately 3-fold increased risk of symptomatic cerebral infarction and an approximately 2.3-fold increased risk of vascular dementia than subjects with normal brain magnetic resonance imaging (MRI) examinations. The Framingham Follow-up Study reported that in a “healthy” population with an average age of 62 years (53% female), 10.7% of subjects who underwent brain MRI had asymptomatic cerebral infarction, with a single cerebral infarct lesion accounting for 84%. Patients with asymptomatic cerebral infarction had a 2-fold increased risk of developing atrial fibrillation compared with subjects with normal brain MRI (risk ratio 2.16; 95% confidence interval 1.07-4.40). So how high the risk of stroke is in patients with atrial fibrillation does not depend on whether the atrial fibrillation is nonparoxysmal, persistent or permanent, or whether the patient with atrial fibrillation has symptoms, but rather on the atrial fibrillation stroke risk score that we will describe below. Any patient with atrial fibrillation must be evaluated for risk of stroke thromboembolism! 4. Stroke risk stratification in patients with atrial fibrillation (CHA2DS2-VASc score) C: heart failure, cardiac insufficiency (1 point), H: hypertension (1 point), A: age (1 point for over 65 years, 2 points for over 75 years), D: diabetes mellitus (1 point), S: previous stroke or transient ischemic attack (2 points), VA: presence of atherosclerosis, including coronary artery disease ( 1 point), and Sc: gender (1 point for female). If a patient with atrial fibrillation has a CHA2DS2-VASc score of 0, then this patient with atrial fibrillation has a low risk of stroke and is a low-risk patient. If a patient with AF has a CHA2DS2-VASc score of 1, the patient has an average risk of stroke and is at intermediate risk. If a patient with atrial fibrillation has a CHA2DS2-VASc score of 2 or more, the patient is at high risk of stroke and is at high risk. For patients at low risk of stroke, the CHA2DS2-VASc score can be evaluated periodically without targeting stroke prevention. For patients at intermediate risk of stroke, antithrombotic therapy (consider anticoagulants such as aspirin or warfarin as appropriate) needs to be considered and the CHA2DS2-VASc score should be evaluated periodically. For patients at high risk of stroke, lifelong treatment for stroke prevention (lifelong anticoagulation with anticoagulants such as warfarin or minimally invasive left-ear occlusion) and periodic evaluation of the CHA2DS2-VASc score are required. In patients with atrial fibrillation at high risk of stroke, the use of antiplatelet agents such as aspirin or clopidogrel (Tagatha, Bolivar, etc.) is not sufficient to prevent stroke and is not recommended.