angina pectoris

Angina pectoris is chest discomfort that arises when the heart muscle asks for more oxygen than its blood supply can deliver. A useful image is a car engine straining up a hill while the fuel line is partly pinched: as long as the car idles on flat ground it runs fine, but the moment it has to work harder, it sputters. The heart, likewise, may feel fine at rest yet complain when demand rises.

The usual culprit is narrowing of the coronary arteries by atherosclerotic plaque, which limits how much blood can flow to the working muscle. Demand climbs with exertion, cold, heavy meals, or emotional stress; when supply cannot keep up, the under-fed muscle signals distress as a pressing or tight ache, often behind the breastbone and sometimes radiating to the arm, jaw, or shoulder. Resting or taking a nitrate widens the vessels and relieves the imbalance, so the pain typically fades within minutes.

Angina is a symptom, not a diagnosis in itself. When the pattern is predictable and exertion-related it is called stable angina; when it appears at rest, worsens quickly, or comes with less and less effort it is called unstable angina and signals a higher-risk situation. The distinction matters because unstable angina can be the prelude to a heart attack and warrants prompt assessment.