Syndrome X: causes, symptoms, diagnosis, treatment

Syndrome X is a dysfunction or constriction of the microcirculatory vessels, leading to the onset of an attack of angina pectoris (angina).

Some patients with typical angina that is relieved by rest or nitroglycerin have normal coronary angiography (that is, no atherosclerotic lesions, emboli, or inducible arterial spasm). Some of these patients have ischemia detectable on stress testing; others do not. In some patients, the ischemia probably results from reflex narrowing of intramural arteries and decreased coronary reserve. Other patients have microvascular dysfunction within the myocardium: the abnormal vessels do not dilate in response to exercise or other cardiovascular stimuli; sensitivity to cardiac pain may also be increased in these patients. The prognosis is good, although evidence of ischemia may persist for years. In many patients, beta-blockers lessen the symptoms. This pathology should not be confused with variant angina associated with spasm of the epicardial arteries, or with another pathology also called "syndrome X", which refers to the metabolic syndrome.

Painless ischemia

Patients with coronary artery disease (especially those with diabetes) may have ischemia without clinical manifestations. Evidence of ischemia is transient asymptomatic ST-T changes detected during 24-hour Holter monitoring. Myocardial scintigraphy can also sometimes detect asymptomatic ischemia during physical or mental exertion (e.g., mental arithmetic). Silent ischemia and angina may coexist, manifesting at different times. The prognosis depends on the severity of coronary artery disease.