What is a key feature of unstable angina?

Unstable angina is characterized as a form of chest pain or discomfort that occurs unpredictably and is not solely triggered by physical activity or exertion. This is a key distinguishing feature, as it can occur at rest, during sleep, or with minimal exertion, which differentiates it from stable angina that typically presents in response to physical stress.

Additionally, unstable angina is often more intense and lasts longer than stable angina and can happen without any apparent precipitating factors. This unpredictability makes unstable angina particularly concerning, as it signals a change in the pattern of angina and indicates a higher risk for acute coronary events.

While unstable angina doesn't always signify an imminent heart attack, it often indicates significant underlying coronary artery disease and requires immediate medical attention to prevent progression to myocardial infarction.