Which term describes unstable angina?

• A. Constant
• B. Predictable
• C. Unpredictable
• D. Intermittent

Answer: (C)

Unstable angina is described by the unpredictable timing and pattern of chest pain. Unlike stable angina, where pain occurs with effort in a fairly regular way and eases with rest or nitroglycerin, unstable angina can flare up suddenly, even at rest, and its frequency and intensity can change. Because the hallmark is that the episodes come in an unpredictable, evolving pattern, the best term to describe it is unpredictable.

Constant would imply continuous pain, which isn’t typical for unstable angina. Predictable suggests a regular, expected pattern, which contradicts the unstable nature. Intermittent might imply recurring episodes, but not the sense of changeable and unscheduled risk that defines instability. Understanding that the key feature is unpredictability helps recognize why this condition signals a higher risk that needs urgent assessment.