Premature beats are very common in normal people, and if an ECG is used to continuously observe a normal person for 24 hours, it is possible to record 70-80% of premature beats; although premature beats are irregular heartbeats, they are not always caused by diseases. Premature beats can be caused by exertion, emotional stress, excitement, anxiety, excessive smoking, heavy alcohol consumption, strong tea, or even constipation. Many diseases can also cause premature beats: for example, patients with non-cardiac diseases such as hyperthyroidism, anemia, hypokalemia, fever, etc. can have premature beats. Various heart diseases can cause premature beats, but premature beats are more common in heart diseases such as rheumatic heart disease, coronary arteriosclerotic heart disease, myocarditis and cardiomyopathy.