The exact life expectancy of a 45-year-old patient with atrial fibrillation depends largely on the condition and cannot be generalized. In the case of atrial fibrillation with idiopathic attacks, the patient has no obvious trigger and will have a sudden attack, which may also be aborted suddenly. This type of atrial fibrillation usually does not affect the patient’s life expectancy as long as he or she pays attention to a reasonable diet, moderate physical exercise, and emotional control. However, if atrial fibrillation is caused by primary diseases, such as myocardial infarction, rheumatic heart valve disease, coronary artery disease, etc., the primary disease should be treated first. If the primary disease is poorly controlled, atrial fibrillation is also poorly controlled and there is a risk of stroke and heart failure, which can increase the mortality rate of patients. If atrial fibrillation is combined with chronic heart failure, the patient’s survival rate is only 50% at 4 years, and if the disease is more severe, the survival rate is only 50% at 1 year. Patients with atrial fibrillation at the age of 45 are advised to pay attention to lifestyle improvement, moderate low-salt diet, and avoid factors that increase myocardial oxygen consumption, cardiac load and sympathetic excitation, such as avoiding excessive emotional excitement.