A 58-year-old man is diagnosed with an acute anterior STEMI and undergoes successful primary PCI. Which cardiac biomarker is most useful for detecting a reinfarction occurring 72 hours after the initial event?

• A Cardiac troponin I
• B Cardiac troponin T
• C Lactate dehydrogenase
• D Creatine kinase-MB (CK-MB) ✓

Explanation

CK-MB returns to baseline within 48 to 72 hours due to its shorter half-life, whereas troponins remain elevated for 7 to 14 days. Therefore, CK-MB is the preferred biomarker to detect reinfarction or infarct extension after the first 48 to 72 hours when troponin levels are still elevated from the initial event.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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