Atrial fibrillation

Atrial fibrillation is one of the rapid atrial ectopic arrhythmias, more common in the elderly, and the older the age, the greater the likelihood of occurrence. In patients with this disease, the atrial muscle fibers show incoordinate fibrillation at 400–600 times per minute, with only a portion conducted to the ventricles. The ventricular beats are rapid and irregular, at 120–160 times per minute, and it is one of the common arrhythmias. It can be paroxysmal or persistent; the former occurs at irregular intervals, while the latter lasts more than 6 months. Atrial fibrillation mostly occurs in patients with organic heart disease, with rheumatic mitral stenosis being the most common. Next are coronary heart disease, hypertensive heart disease, and hyperthyroidism. It can also be seen in constrictive pericarditis, cardiomyopathy, and myocarditis. It can also be caused by thoracic or cardiac surgery, pneumonia or other acute infections, and digitalis toxicity. About 5–6% of patients (mostly paroxysmal) have no evidence of heart disease, termed "idiopathic" or "benign" atrial fibrillation. After cardioversion of atrial fibrillation, medication is often needed to prevent recurrence, with quinidine being the first choice, followed by procainamide. A few patients, such as those after control of hyperthyroidism or after mitral valve surgery, may discontinue medication after 1–2 weeks; other patients require long-term maintenance. In addition, digoxin, metoprolol, and others are used to control the ventricular rate in patients with atrial fibrillation, maintaining the ventricular rate at the ideal standard of 60–70 beats per minute. Anticoagulant drugs such as warfarin or aspirin should be taken consistently to prevent thrombus formation in the left atrial appendage and prevent dangerous events such as stroke.