Syndrome X (Microvascular Angina)
Syndrome X is cardiac microvascular dysfunction or constriction causing angina in patients with normal epicardial coronary arteries on angiography.
(See also Overview of Coronary Artery Disease.)
Patients with cardiac syndrome X have
Typical angina that is relieved by rest or nitroglycerin
Normal coronary arteriograms (eg, no atherosclerosis, embolism, or inducible arterial spasm)
Some of these patients have ischemia detected during stress testing; others do not. In some patients, the cause of ischemia seems to be reflex intramyocardial coronary constriction and reduced coronary flow reserve. Other patients have microvascular dysfunction within the myocardium: The abnormal vessels do not dilate in response to exercise or other cardiovascular stressors; sensitivity to cardiac pain may also be increased.
Prognosis is better than for patients with demonstrable coronary artery disease, although symptoms of ischemia may recur for years.
In many patients, beta-blockers relieve symptoms.
Drug NameSelect Trade