What clinical condition is characterized by an imbalance of oxygen delivery vs. oxygen demand?

Stable angina is characterized by a predictable pattern of chest discomfort due to an imbalance between myocardial oxygen supply and demand, often triggered by physical exertion or emotional stress. During episodes of stable angina, the heart's oxygen demand increases (for example, during exercise), but the coronary arteries are unable to supply enough oxygen due to atherosclerosis or other underlying conditions. This leads to transient ischemia and subsequent chest pain, which typically resolves with rest or nitroglycerin.

In contrast, unstable angina involves more unpredictable chest pain that can occur at rest or with minimal exertion. It reflects a more significant disruption in blood flow, often indicating an impending myocardial infarction. STEMI and NSTEMI also involve ischemic events but are generally more acute and represent more severe tissue damage and oxygen deprivation compared to stable angina. Thus, stable angina fits the description of an imbalance between oxygen delivery and demand without acute injury to myocardial tissue.