Which of the following flipped pattern of LDH is seen in myocardial infarction:
**Core Concept**
In myocardial infarction, there is an initial release of LDH-2, but as the infarcted tissue breaks down, LDH-1 levels rise, leading to a characteristic "flipped" pattern. This phenomenon is crucial in differentiating myocardial infarction from other forms of tissue damage.
**Why the Correct Answer is Right**
In myocardial infarction, the initial rise in LDH-2 is due to the release of this enzyme from the cytosol of damaged cardiac cells. As the infarcted tissue undergoes necrosis, LDH-1, which is primarily located in the mitochondria, is released into the bloodstream, causing the LDH-1 to LDH-2 ratio to become elevated. This is a critical distinction, as in other forms of tissue damage, such as liver disease, LDH-2 levels typically remain higher than LDH-1.
**Why Each Wrong Option is Incorrect**
* **Option B:** LDH 2>1 is the typical pattern seen in liver disease and other forms of tissue damage, not myocardial infarction.
* **Option C:** LDH 3>4 is not a recognized pattern in the context of LDH isoenzymes and myocardial infarction.
* **Option D:** LDH 5>4 is not relevant to the flipped pattern of LDH seen in myocardial infarction.
**Clinical Pearl / High-Yield Fact**
Remember the "flipped" LDH pattern in myocardial infarction: an initial rise in LDH-2 followed by an increase in LDH-1, which can help differentiate this condition from other forms of tissue damage.
✓ Correct Answer: A. LDH 1>2