Atrial fibrillation is the most common atrial arrhythmia. Atrial fibrillation is caused by an abnormally fast discharge from an ectopic pacing site in the atrial tissue and an imbalance in the conduction of electrical signals in all directions. In normal sinus rhythm, the heart beats 60-100 times/minute at a regular frequency, so the atrial contractions are coordinated; in atrial fibrillation, the atria contract very rapidly, usually 300-600 times/minute, at a highly irregular frequency, resulting in extremely uncoordinated atrial contraction and diastole, resulting in atrial fibrillation. Atrial fibrillation can occur independently, but does have a number of risk factors that can increase the formation of atrial fibrillation. These factors include: 1. Coronary heart disease, heart valve disease, congestive heart failure. 2, High blood pressure and diabetes. 3, Thyroid, lung, or neurological disease. 4, Excessive intake of caffeine or alcohol.