Ischemia is best defined as which?

• A. Inadequate blood supply
• B. Excessive blood flow
• C. Complete tissue death
• D. Intermittent chest pain

Answer: (A)

Ischemia means a reduced blood supply to a tissue, which leads to insufficient oxygen and nutrients for normal cellular metabolism. In the heart, when coronary blood flow is limited, cells are deprived of oxygen, which can cause symptoms like chest discomfort during activity, but the core issue is the supply shortage, not the pain itself. If blood flow is restored in time, tissue can recover; prolonged ischemia can progress to tissue death (infarction). The other options miss the defining feature: excessive blood flow would be hyperemia; complete tissue death describes infarction/necrosis; intermittent chest pain can be a sign of ischemia but is not the definition itself.