Angina, variant: Chest pain due to coronary artery spasm, a sudden constriction of a coronary artery (one of the vessels that supply the heart muscle with blood rich in oxygen) depriving the heart muscle (myocardium) of blood and oxygen. This is also called Prinzmetal angina.

Coronary artery spasm can be triggered by emotional stress, medicines, street drugs (cocaine) or exposure to cold. Treatments include beta- blocker medications and, classically, nitroglycerin to permit the coronary arteries to open up (dilate).