What is atrial fibrillation? Atrial fibrillation is the most common type of atrial arrhythmia. Atrial fibrillation is caused by abnormal rapid discharge of ectopic pacing points in the atrial tissue and uneven conduction of electrical signals in all directions. In normal sinus rhythm, the heart beats at 60-100 beats per minute with a regular frequency, so that the contractions of the atria are coordinated, whereas in atrial fibrillation, the atria contract very rapidly, usually at 300-600 beats per minute, with a highly irregular frequency, resulting in a highly uncoordinated contraction and diastole of the atria, resulting in atrial fibrillation. In atrial fibrillation, the rapid irregular rhythm of the atria is transmitted to the ventricles, causing rapid irregularities in the ventricular rate, so that patients with atrial fibrillation feel palpitations. The rapid irregular contraction of the ventricles also causes a significant decrease in ventricular pumping function. The reduced pumping of the heart can cause the brain and other organs of the body to be deprived of adequate blood supply. As a result, patients may experience shortness of breath, dizziness, fatigue and, in severe cases, fainting. When the ventricular rate is not fast, there are also some patients who have no symptoms and do not even know they have atrial fibrillation.