Myocardial ischemia may be the cause of premature ventricular contractions. When patients have myocardial ischemia, such as coronary artery stenosis in patients with coronary artery disease causing myocardial ischemia, the electrical activity of the ischemic myocardium is abnormal, leading to arrhythmias such as premature ventricular beats. However, other causes may also lead to premature ventricular contractions, such as prolonged exertion, mental stress, smoking, drinking alcohol or coffee and other causes leading to autonomic dysfunction and premature ventricular contractions. In addition, hypokalemia and hypomagnesemia can also induce premature ventricular contractions, usually unrelated to myocardial ischemia. If a patient develops premature ventricular contractions, it is recommended to visit the cardiology department of the hospital in time to find out the cause.