Which type of angina is characterized as stable, unstable, or variant?

Printzmetal angina, also known as variant angina, is characterized by episodes of chest pain that occur at rest and are often associated with coronary artery spasm. This type of angina can arise unpredictably and is not necessarily linked to physical exertion or stress.

In contrast to stable angina, which occurs with exertion and is relieved by rest or nitroglycerin, Printzmetal angina can happen at any time and is specifically due to a temporary reduction in blood flow caused by spasms of the coronary arteries. Unstable angina, which is a part of acute coronary syndrome, is characterized by changes in pattern, severity, or frequency of chest pain.

While chronic stable angina is a common form of exertional angina and responds well to rest, it does not encompass the spontaneous nature of Printzmetal angina. This distinction makes Printzmetal angina a unique and identifiable form within the spectrum that also includes stable and unstable angina, as well as other syndromes.