If a patient experiences this discomfort, it is highly considered to be due to coronary artery disease and angina pectoris. Patients are advised to take sublingual nitroglycerin during the onset of discomfort. If the patient can get some degree of relief after taking nitroglycerin, it is more likely to be due to coronary artery disease and angina pectoris. If relief cannot be obtained, it is advisable for the patient to go further to the emergency department for cardiac enzymes and electrocardiogram to help clarify whether acute coronary syndrome is currently occurring. Certain patients may have a duodenal ulcer with bile reflux gastritis, and there are also some patients in whom cardiac neurosis cannot be excluded as a cause. Patients with cardiac neuropathy are also prone to this uncomfortable symptom. It is recommended that the patient undergo a coronary CT examination to help identify whether there is a more severe stenosis of the current coronary vessels.