Premature beats are generally categorized into atrial premature beats and ventricular premature beats. In terms of complications and symptoms, ventricular premature beats are relatively more serious than atrial premature beats. 1. Atrial premature beats: When premature beats occur in the patient’s atrium, they are called atrial premature beats, and most patients may be asymptomatic. If atrial premature beats occur frequently, symptoms such as palpitations, fatigue and chest tightness may occur, and in severe cases, they may progress to atrial flutter, atrial fibrillation, and other cardiac arrhythmias. 2. Ventricular premature beats: When premature beats occur in the patient’s ventricle, they are called ventricular premature beats. Ventricular premature beats may occur in a small number of healthy people, but they are common in all kinds of organic heart disease, and patients may have symptoms such as palpitations and chest tightness. Frequent ventricular premature beats may also cause dizziness and blackouts. Certain premature ventricular beats may also induce ventricular tachycardia or even ventricular fibrillation, leading to fainting, convulsions and, in severe cases, sudden death. Therefore, premature ventricular contractions are more serious, and patients who experience frequent palpitations, chest tightness, dizziness, blackouts, etc. are advised to seek timely medical attention.