What characterizes unstable angina?

Unstable angina is characterized by episodes of chest pain that are either new in onset, increasing in frequency or intensity, or occur at rest. This type of angina represents a significant change in a patient's typical pattern of angina and is associated with a higher risk of myocardial infarction.

In unstable angina, the unpredictability is key, as the pain may arise spontaneously even during periods of rest or with minimal exertion, distinguishing it from stable angina, which is predictable and occurs with exertion. The episode duration may also vary, and the pain may not respond as reliably to rest or nitroglycerin as stable angina does. This variability and intensity suggest that there is an underlying process, such as plaque rupture or thrombus formation, that increases the risk of serious cardiovascular events.

Understanding the nature of unstable angina is crucial in managing patients appropriately and determining immediate intervention strategies to prevent progression to a myocardial infarction.