Which isoenzyme of LDH has the HIGHEST concentration in the myocardium and shows flip pattern in myocardial infarction?

• A LDH-2 (H3M)
• B LDH-3 (H2M2)
• C LDH-5 (M4)
• D LDH-1 (H4) ✓

Explanation

LDH-1 (comprising four H subunits, H4) predominates in cardiac muscle and erythrocytes. Normally LDH-2 > LDH-1 in serum; after myocardial infarction, LDH-1 exceeds LDH-2 — the 'flip' pattern — which develops 24–48 hours post-infarction and can persist for 10–14 days. LDH-5 (M4) predominates in skeletal muscle and liver.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.