**Core Concept**
Lactate dehydrogenase (LDH) isoenzymes are used to localize cardiac injury. LDH-1 and LDH-2 are the key isoenzymes in myocardial tissue, with LDH-1 being predominantly cardiac. A ratio of LDH-1 > LDH-2 indicates myocardial infarction due to the higher concentration of cardiac-specific LDH-1 in heart muscle.

**Why the Correct Answer is Right**
In myocardial infarction, cardiac tissue releases LDH-1 into the bloodstream. LDH-1 is more abundant in cardiac muscle than in skeletal muscle, and its release exceeds that of LDH-2. The ratio LDH-1 > LDH-2 is a specific marker for myocardial injury. This pattern is distinct from skeletal muscle or liver damage, where LDH-2 dominates.

**Why Each Wrong Option is Incorrect**
Option B: LDH-2 > LDH-1 is seen in skeletal muscle injury or liver disease, not myocardial infarction.
Option C: LDH-4 and LDH-5 are primarily found in skeletal muscle and liver, not cardiac tissue.
Option D: LDH-5 > LDH-4 is associated with liver or renal disease, not myocardial infarction.

**Clinical Pearl / High-Yield Fact**
Remember: **LDH-1 > LDH-2 = myocardial injury**. This is a classic, high-yield point in cardiology for diagnosing acute myocardial infarction using enzyme patterns.

✓ Correct Answer: A. LDH-1> LDH-2