Which pattern of infarction involves only small intramural vessels and is sometimes associated with epinephrine?

Which pattern of infarction involves only small intramural vessels and is sometimes associated with epinephrine?

• A. Subendocardial infarction
• B. Transmural infarction
• C. Multifocal microinfarction
• D. Global infarction

Answer: (C)

Infarction patterns reflect the size of the vessels involved. When only tiny intramural vessels are affected, the resulting damage is small and scattered across the myocardium—multifocal microinfarctions. This pattern arises from occlusion or marked spasm of microvessels, which can be triggered by agents like epinephrine that cause vasoconstriction in small arteries. Because the injury stays confined to these small vessels, you don’t get a single large area of necrosis or full-thickness wall involvement. By contrast, subendocardial infarction involves the inner layer due to global hypoperfusion or partial occlusion of a major artery, transmural infarction spans the full thickness from a major epicardial occlusion, and global infarction reflects widespread hypoperfusion.

Infarction patterns reflect the size of the vessels involved. When only tiny intramural vessels are affected, the resulting damage is small and scattered across the myocardium—multifocal microinfarctions. This pattern arises from occlusion or marked spasm of microvessels, which can be triggered by agents like epinephrine that cause vasoconstriction in small arteries. Because the injury stays confined to these small vessels, you don’t get a single large area of necrosis or full-thickness wall involvement. By contrast, subendocardial infarction involves the inner layer due to global hypoperfusion or partial occlusion of a major artery, transmural infarction spans the full thickness from a major epicardial occlusion, and global infarction reflects widespread hypoperfusion.