Abnormal Q waves are Q waves with a duration greater than 0.04S and a depth greater than 1/4 of the R wave in the same lead. Abnormal Q waves are an indication of coronary artery disease. They can be seen on the ECG of patients with acute myocardial infarction or old myocardial infarction, but less frequently, they can also be seen on the ECG of normal individuals. Therefore, abnormal Q waves need to be combined with the patient’s medical history and clinical presentation to determine the patient’s current condition. Patients with abnormal Q waves, along with severe pain and tightness in the precordial region, are often considered to have myocardial infarction and require emergency treatment, otherwise their lives are at risk. Patients with abnormal Q waves and a previous history of myocardial ridge infarction are more likely to be considered old myocardial ridge infarction and should be reviewed regularly. Therefore, abnormal Q waves are usually an indication of coronary heart disease, but can also occur in normal people.