Which of the following is a classic symptom of unstable angina?

Unstable angina is characterized by chest pain that occurs unpredictably and can happen at rest or with minimal exertion, differing from stable angina, which typically manifests during physical activity and is often relieved by rest or medications. The defining feature of unstable angina is its intensity, duration, or frequency, which can indicate a worsening of coronary artery disease and an increased risk for myocardial infarction.

In this context, chest pain occurring at rest is a classic symptom of unstable angina because it signifies that the heart muscle is not receiving enough oxygen, despite the lack of exertion. This symptom is concerning and necessitates immediate medical evaluation, as it may herald that the coronary arteries are substantially narrowed or that a thrombus has formed, impeding blood flow.

Other symptoms of unstable angina can include pain that lasts longer than typical angina episodes, pain that is more severe, or an increase in the frequency of episodes. Recognizing chest pain at rest as a critical sign of unstable angina helps inform prompt treatment and potential intervention.