Atrial fibrillation, or AF for short, is one of the most common clinical arrhythmias. In atrial fibrillation, the direction of excitation conduction in the atria is inconsistent, the frequency is fast and irregular, and the atria lose their effective contraction function. In atrial fibrillation, the frequency of atrial excitation is as high as 300-600 beats/min. Although the protective effect of the AV node prevents all these excitations from reaching the ventricles, the ventricular rate (heart rate) can still reach 100-160 beats/min, which is faster than the normal sinus heart rate, and the rhythm is definitely irregular. Patients often present with a fast and irregular self-perceived heartbeat and an irregular pulse. The electrocardiogram in atrial fibrillation is shown in the figure below. Atrial fibrillation can be classified into five categories according to the timing and characteristics of the patient’s atrial fibrillation episodes: primary atrial fibrillation, paroxysmal atrial fibrillation, persistent atrial fibrillation, permanent atrial fibrillation and long-range persistent atrial fibrillation. Paroxysmal atrial fibrillation refers to those who can convert to sinus rhythm on their own within 7 days, and the duration of atrial fibrillation is usually <48 hours; persistent atrial fibrillation refers to those who persist for more than 7 days and require pharmacological or electrical resuscitation to convert to sinus rhythm; permanent atrial fibrillation refers to those who cannot convert to sinus rhythm, or whose physicians and patients have accepted that the persistence of atrial fibrillation does not intend to convert to sinus rhythm; when atrial fibrillation lasts for more than 1 year and is considered When atrial fibrillation persists for more than 1 year and conversion to sinus rhythm is considered (e.g., radiofrequency ablation procedure is proposed), it is called long-range persistent atrial fibrillation. Classification of atrial fibrillation 1. Primary atrial fibrillation First occurrence or first diagnosis of atrial fibrillation, regardless of the duration and severity of symptoms. 2, Paroxysmal atrial fibrillation Those who revert to sinus rhythm on their own within 7 days, usually with a duration <48 hours. 3.Persistent atrial fibrillation Those who persist for more than 7 days and require medication or electrical resuscitation to return to sinus rhythm. 4.Permanent atrial fibrillation cannot be converted to sinus rhythm, or the physician and the patient have accepted that the persistence of atrial fibrillation is not intended to be converted to sinus rhythm. 5. Long-term persistent atrial fibrillation Atrial fibrillation lasting for more than 1 year and considered for conversion to sinus rhythm.