The difference between atrial fibrillation and premature beats is mainly the following: 1. The cause of atrial fibrillation is the presence of abnormal electrical activity at the entrance of the pulmonary veins in the atria, which interferes with the normal electrical conduction of the heart and eventually causes irregular and rapid atrial fibrillation and an increase in the ventricular rate. 2. The hazards of atrial fibrillation are different. Atrial fibrillation has the risk of heart enlargement, heart failure, intra-atrial thrombosis and cerebral thromboembolism, while premature beats do not have the above-mentioned risks. 3. The symptoms of the two are different: atrial fibrillation has obvious symptoms of panic, chest tightness and shortness of breath, while most patients with occasional premature beats do not have any symptoms. The electrocardiogram is visible with atrial fibrillation waves, no sinus rhythm, and absolutely uneven heart rhythm, while in premature beats, the heart rhythm is still sinus rhythm with occasional uneven heart rhythm.