Types of angina

Angina is chest pain or discomfort that occurs when there is too little blood flowing to the heart muscle. It is often the result of coronary artery disease and narrowing of the blood vessels that supply the heart muscle.

There are several types of angina. The most common type is stable angina, which occurs at predictable times with a specific amount of exertion or activity. It is relieved by rest and may continue without much change for years.

Unstable angina is a change in the usual pattern of stable angina or a new severe angina that means blood flow has decreased. In unstable angina, chest pain occurs at rest or with less and less exertion, may be more severe and last longer, or no longer responds to nitroglycerin.

Angina caused by coronary artery spasms results from a coronary artery that suddenly contracts (spasms), reducing oxygen-rich blood flow to the heart. If severe, a spasm can block blood flow and cause a heart attack. Most of the time coronary artery disease is involved, although sometimes plaque is not present. Cocaine can cause coronary artery spasm and heart attack, but in most cases it is not known what triggers them.

Variant angina, also called Prinzmetal's angina or vasospastic angina, is also caused by coronary artery spasm. However, it has a distinctive pattern. It usually occurs when you are at rest and without apparent cause. It occurs more often at night, in the early morning hours, or at the same time of the day. The spasm often occurs at the site of coronary artery narrowing from plaque, although it can also occur in healthy coronary arteries. Variant angina episodes typically last 2 to 5 minutes and quickly subside with nitroglycerin.

Abnormal heartbeats, such as ventricular tachycardia, often occur during variant angina episodes and may cause fainting.