Microvascular angina pectoris, also known as cardiac syndrome X, usually refers to a patient with angina pectoris or with symptoms similar to angina pectoris, an episode with myocardial ischemia on electrocardiogram, and a positive exercise test without abnormal findings on coronary angiography. The pathogenesis of the disease is still unclear, but several theories have been proposed. The two most prominent hypotheses are (1) microvascular dysfunction, where chest pain symptoms are thought to be caused by abnormal function of the coronary microcirculation leading to myocardial ischemia, and (2) abnormal cardiac pain sensitivity, where chest pain symptoms are thought to be caused by hypersensitivity to cardiac pain sensitivity. In different patients, different mechanisms can act synergistically to cause chest pain, or there may be different underlying etiologies. Conventional anti-myocardial ischemic drugs can be used for treatment, commonly used beta-receptor antagonists such as metoprolol and bisoprolol; nitrates such as isosorbide dinitrate; angiotensin-converting enzyme inhibitors such as quinapril; and calcium channel blockers, nondihydropyridines such as verapamil, and dihydropyridines such as nifedipine. The drug nicorandil also improves angina symptoms and can consistently improve prognosis. Meanwhile, for refractory microvascular angina the psychotropic drug promethazine can be applied to relieve chest pain symptoms. This treatment varies from patient to patient, with some patients experiencing symptomatic improvement and others not. Such cases require prompt medical attention and treatment as prescribed by the doctor.