Tigered effect in myocardium is due to:
**Core Concept**
The "tigered effect" in myocardium refers to a specific histopathological pattern characterized by alternating areas of necrosis and viable myocardium, resembling the stripes of a tiger. This phenomenon is a manifestation of a particular type of myocardial injury.
**Why the Correct Answer is Right**
The tigered effect is typically observed in myocardial infarctions caused by coronary emboli, particularly those composed of cholesterol crystals or platelet aggregates. This type of embolus causes a segmental, patchy pattern of necrosis due to the abrupt interruption of blood flow to the affected area. The alternating zones of necrosis and viable myocardium result from the variable size of the emboli and the subsequent distribution of ischemic damage.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the tigered effect is not typically associated with large, transmural infarctions caused by atherosclerotic plaque rupture or thrombosis.
**Option B:** This option is incorrect because the "tigered effect" does not refer to a specific pattern of myocardial fibrosis or scarring.
**Option C:** This option is incorrect because the tigered effect is not a characteristic finding in myocarditis, which typically presents with a more diffuse pattern of inflammation and necrosis.
**Clinical Pearl / High-Yield Fact**
The tigered effect is an important diagnostic clue in identifying coronary emboli as the cause of myocardial infarction, especially in young patients without significant atherosclerotic disease.
**Correct Answer:** D.