Atrial flutter and atrial fibrillation both belong to atrial arrhythmia, the main difference between the two is the different electrocardiogram performance, characteristics, atrial rate and so on. 1. Electrocardiogram: in atrial flutter, the P wave disappears and is replaced by a relatively uniform large F wave, and the ventricular rate is regular or irregular depending on whether the ratio of atrioventricular conduction is constant or not; while in atrial fibrillation, the P wave disappears and is replaced by a small F wave, and the ventricular rate is absolutely irregular. 2. Characteristics: In atrial flutter, the strength of the first heart sound varies with the ratio of atrioventricular conduction, and the rhythm is relatively neat, while in atrial fibrillation, the rhythm is absolutely irregular, the strength of the first heart sound varies, and the number of pulses and the heart rate are not equal. 3. Atrial rate: the frequency of atrial flutter is slower in atrial flutter and faster in atrial fibrillation. Generally atrial flutter is in the atria, and its flutter frequency is about 250~350 beats/minute, while the frequency of atrial fibrillation should reach 350~600 beats/minute. Whether the two symptoms depend on the ventricular rate, the ventricular rate is not fast, can be asymptomatic, too fast, can be induced angina pectoris and congestive heart failure; in addition, long-term episodes can be produced by atrial thrombosis; so the above performance need to consult a doctor in a timely manner, under the guidance of the doctor’s standardization of treatment, so as to avoid delays in the condition.