Variant angina, also known as Prinzmetal angina, vasospastic angina, angina inversa, coronary vessel spasm, or coronary artery vasospasm, is a syndrome typically consisting of angina (cardiac chest pain). Variant angina differs from stable angina in that it commonly occurs in individuals who are at rest or even asleep, whereas stable angina is generally triggered by exertion or intense exercise. Variant angina is caused by vasospasm, a narrowing of the coronary arteries due to contraction of the heart's smooth muscle tissue in the vessel walls. In comparison, stable angina is caused by the permanent occlusion of these vessels by atherosclerosis, which is the buildup of fatty plaque and hardening of the arteries.
In contrast to those with angina secondary to atherosclerosis, people with variant angina are generally younger and have fewer risk factors for coronary artery disease with the exception of smoking, which is a common and significant risk factor for both types of angina. Affected people usually have repeated episodes of unexplained (e.g., in the absence of exertion and occurring at sleep or in the early morning hours) chest pain, tightness in throat, chest pressure, light-headedness, excessive sweating, and/or reduced exercise tolerance that, unlike atherosclerosis-related angina, typically does not progress to myocardial infarction (heart attack). Unlike cases of atherosclerosis-related stable angina, these symptoms are often unrelated to exertion and occur in night or early morning hours. However, individuals with atherosclerosis-related unstable angina may similarly exhibit night to early morning hour symptoms that are unrelated to exertion.
Cardiac examination of individuals with variant angina is usually normal in the absence of current symptoms. Two-thirds of these individuals do have concurrent atherosclerosis of a major coronary artery, but this is often mild or not in proportion to the degree of their symptoms.