What is the difference between stable and unstable angina?

The distinction between stable and unstable angina is primarily centered around the predictability and conditions associated with the episodes. Unstable angina is characterized by episodes that occur unpredictably, often at rest, and may signify a more serious condition such as an impending heart attack. This type of angina can last longer, may not respond to rest or nitroglycerin, and indicates a higher risk for cardiovascular events.

In contrast, stable angina typically occurs during physical exertion or stress and is predictable. It generally resolves with rest or the use of medications like nitroglycerin. Therefore, the identification of unstable angina as unpredictable and occurring at rest highlights a significant difference in the presentation and implications of these two conditions, emphasizing the urgency of medical evaluation and intervention in cases of unstable angina.