If you repeatedly feel chest tightness, shortness of breath, accompanied by chest pain, you should first exclude coronary angina and coronary myocardial infarction. Coronary angina is divided into stable and unstable type, stable type of patients with mild nature of pain, and generally shorter duration, mostly about 5 minutes not more than 15 minutes, rest or stop exercise that can be quickly improved. But for the unstable type of angina pectoris of coronary heart disease, patients tend to last longer and the pain is more frequent, and after taking nitroglycerin, the effect is slightly worse than before. In the case of acute myocardial infarction in coronary artery disease, there is usually no significant improvement after taking nitroglycerin, and the patient’s pain is more intense in nature, accompanied by significant sweating, and even back pain and tightness in the throat, toothache, epigastric pain, and other atypical pain. For patients with coronary angina and coronary myocardial infarction, they should actively go to the hospital for an electrocardiogram to determine whether there is a manifestation of myocardial ischemia; a cardiac ultrasound to determine whether there is a significant decrease in the ejection fraction of the heart; and a coronary CT or coronary angiography to determine whether there is a significant narrowing of the three coronary arteries of the heart.