Diltiazem belongs to the non-dihydropyridine class of calcium antagonists and can be used in the treatment of arrhythmias, in the treatment of acute hypertension, and in the treatment of acute coronary syndromes for the relief of spasm of coronary arteries. Diltiazem has a place in the treatment of arrhythmias, such as paroxysmal supraventricular tachycardia, atrial flutter, and atrial fibrillation, because of its negative inotropic and negative heart rate effects. In patients with hypertension, because the negative inotropic effect of diltiazem can cause a decrease in blood pressure and heart rate, it can be used for application in the diagnosis and treatment of postoperative or hypertensive crisis. In addition, for unstable angina pectoris due to coronary artery spasm, myocardial infarction and slow coronary artery flow states, diltiazem can play a corresponding role in relieving spasm and improving ischemia.