What are the different types of angina pectoris?

Angina pectoris is chest discomfort or shortness of breath caused when heart muscles receive insufficient oxygen-rich blood. There are several types of angina, including stable angina, unstable angina, variant angina (also known as Prinzmetal’s angina), and microvascular angina.

Stable angina follows a regular pattern in terms of frequency, intensity, and duration and is fairly predictable, normally occurring after physical and mental exertion. Unstable angina occurs usually due to reduced blood flow because of fatty deposits (plaque) rupture or forming a clot in the coronary arteries. The symptoms worsen while at rest and may be a medical emergency. Variant angina is a rare form of angina that occurs at rest. The chest pain is caused by coronary artery spasm, a sudden constriction of a coronary artery resulting in a decrease in blood supply to the region supplied by the artery. Microvascular angina is chest pain that occurs when the small blood vessels that feed the heart muscle are not functioning properly.