Atrial fibrillation is a common condition in older people for a number of reasons, age itself being a factor. The greatest risk of atrial fibrillation is ischemic stroke, also known as cerebral thrombosis. Doctors will assess the risk of cerebral thrombosis and administer prophylactic anticoagulation depending on the patient’s condition. How is the risk of ischemic stroke assessed in patients with atrial fibrillation? The first thing to know is that patients with paroxysmal AF are at the same risk of ischemic stroke as those with persistent AF. Second, ischemic stroke risk is assessed using a complex scoring system. For each patient with atrial fibrillation, physicians assess the patient’s risk of future ischemic stroke using the CHA2DS2-VASc risk scoring system based on the history and medical records. It was found that patients with very low scores on the previous CHADS2 risk score were not treated for ischemic stroke prevention, but the incidence of ischemic stroke in these patients was found to be not low, and these patients were found to have low ischemic stroke risk scores on the CHA2DS2-VASc risk score and to be a group of patients in need of preventive treatment. Therefore, the CHA2DS2-VASc risk scoring system is currently used to predict the risk of future ischemic stroke. How is the risk of ischemic stroke calculated? The two largest ischemic stroke risk factors are history of stroke and age (S2, A2), with a history of stroke scoring 2 points, age over 75 years scoring 2 points, and age over 65 years scoring 1 point (A). Comorbidity with diabetes mellitus and peripheral vascular disease will be considered next and will be scored 1 point each based on history (D, V). Because studies have shown that women are at high risk for ischemic stroke, 1 point is credited if they are female (Sc). In addition, if there is a combination of heart failure and hypertension, 1 point each will be credited (C, H). Patients with a total score of 2 or more are treated with anticoagulation. Whether or not to anticoagulate at a total score of 1 is currently controversial. That is, patients with atrial fibrillation who have a combination of one of these risk factors are patients who need anticoagulation. Doctors not only assess the risk of ischemic stroke in patients with atrial fibrillation, but also the risk of bleeding after the application of anticoagulants. Because of the potential for bleeding with anticoagulants, the HAS-BLED Bleeding Risk Scoring System is used to assess the patient’s bleeding risk before anticoagulant therapy is given.The HAS-BLED Bleeding Risk Scoring System consists of 1 point for high blood pressure (H), 1 point for each of the abnormalities of liver and kidney function (A), 1 point for history of stroke (S), 1 point for history of bleeding (B), and 1 point for INR value. 1 (B), 1 point for unstable INR values (L), 1 point for age >65 years (E), and 1 point each for medication and alcohol consumption (D).Patients with a score of 3 or more are patients who require close attention. Which is higher, ischemic stroke risk or bleeding risk? Do some patients not take anticoagulants because their risk of bleeding is higher than their risk of ischemic stroke? This is a commonly misunderstood question; some patients with a high risk of ischemic stroke also have a high risk of bleeding, but the net balance is still that the risk of ischemic stroke is higher and therefore ultimately requires treatment. Physicians, on the other hand, may focus more on bleeding events in anticoagulated patients, and thus patients with a bleeding tendency are likely to lose out on treatment to prevent ischemic stroke. In fact, the patient’s own attitude in deciding on the treatment is very important, and the fact is that there must be thrombosis without anticoagulation, while bleeding events are less likely to occur with anticoagulation. Is aspirin safe and effective? Aspirin is still used by a wide group of people. There is a misconception here that some people, both doctors and patients, believe that aspirin and warfarin are equivalent in terms of preventing the risk of ischemic stroke, while aspirin is superior to warfarin in terms of safety. Therefore, most physicians will give aspirin to patients with a relatively low risk of ischemic stroke, such as a CHA2DS2-VASc score of 1 or 0, and even to patients with a relatively high risk of ischemic stroke, some physicians will give aspirin because of concerns about bleeding complications, believing that the risk of giving aspirin is not negligible. However, we have evidence, such as the BAFTA trial, that not only is aspirin less effective than warfarin in preventing ischemic stroke in patients with atrial fibrillation, but the risk of bleeding is no less than that of warfarin, especially in older patients. In fact, the risk of ischemic stroke prevention with aspirin is not that good, and the risk of bleeding is not negligible. What are the oral anticoagulants? First of all, we must recognize that in the past, the only medication for preventing ischemic stroke was warfarin, and it is a good thing that we will have more options besides warfarin in the coming decades. Warfarin is considered to be an effective drug for ischemic stroke prevention, but it is clinically inconvenient because of the need for frequent monitoring of indicators such as INR and frequent dose adjustments. In recent years, a number of new oral anticoagulants have been introduced and successively applied in clinical practice, reflecting effectiveness and convenience. These drugs, including dabigatran, apixaban, rivaroxaban, etc., are able to significantly reduce the events of ischemic stroke and systemic embolism as well as being no higher or lower than that of warfarin in terms of the risk of hemorrhage, which is a major step forward. Therefore, patients with atrial fibrillation should receive anticoagulation whenever they are at risk of future ischemic stroke, and the selection of an appropriate anticoagulant is very important.