Enzyme Markers in Myocardial Infarction: Diagnostic and Prognostic Significance of CK-MB, LDH, and Cardiac Troponins

Rahul Eshi1*, Mahima Patil2, Govind Pawar2, Nilesh Salunkhe2

1Assistant Professor, P.G. College of Pharmaceutical Science and Research, Nandurbar (MS), India
2Assistant Professor, NTVS Institute of Pharmacy, Nandurbar (MS), India

Received: 15 Dec 2025 | Published: 01 Jan 2026
Manuscript No: HJBMR-06-25-006 | Download PDF

Abstract

Myocardial infarction (MI) is a leading cause of mortality and long-term disability worldwide. Laboratory-based cardiac biomarkers play a central role in early diagnosis, risk stratification, and prognosis. Among these, creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), and cardiac troponins remain widely used in clinical practice. This review discusses the pathophysiology and morphology of MI and critically evaluates the diagnostic and prognostic significance of these enzyme markers, emphasizing laboratory methodologies, interpretation challenges, and future directions.

Keywords

Myocardial infarction, CK-MB, Lactate dehydrogenase, Cardiac troponin, Cardiac biomarkers, Laboratory diagnosis

Introduction

Myocardial infarction (MI) is defined as irreversible necrosis of cardiac myocytes resulting from prolonged ischemia. The Fourth Universal Definition of MI highlights the importance of cardiac biomarkers—particularly troponins—in modern diagnosis.

Pathophysiology of Myocardial Infarction

MI commonly results from rupture of an atherosclerotic plaque followed by thrombus formation, leading to cessation of coronary blood flow. Prolonged ischemia causes ATP depletion, calcium overload, mitochondrial dysfunction, and eventual myocyte necrosis, resulting in the release of intracellular enzymes into circulation.

Morphology of Myocardial Infarction

Gross morphological changes evolve from pallor and mottling to fibrotic scar formation. Microscopically, coagulative necrosis, inflammatory infiltration, and fibrosis are characteristic.

Cardiac Enzyme Markers

Creatine Kinase-MB (CK-MB)

CK-MB rises within 3–12 hours of MI, peaks at 24 hours, and returns to baseline within 72 hours. It is particularly useful in detecting reinfarction due to its short half-life.

Lactate Dehydrogenase (LDH)

LDH rises later and remains elevated for up to two weeks. Although less specific, it is useful in late presenters.

Cardiac Troponins

Cardiac troponins are the gold standard for MI diagnosis due to their high sensitivity and specificity. High-sensitivity assays allow early rule-in and rule-out strategies.

Laboratory Role in Diagnosis and Monitoring

Serial biomarker testing, quality control, and proper specimen handling are essential. Laboratories play a pivotal role in diagnosis, prognosis, and therapeutic monitoring.

Conclusion

CK-MB, LDH, and cardiac troponins remain indispensable in MI diagnosis and management. Integrated interpretation of biomarkers with clinical and imaging findings improves patient outcomes and guides clinical decision-making.

References

  1. Hajar R. Evolution of myocardial infarction and its biomarkers. Heart Views. 2016.
  2. Kalra A et al. Cardiovascular disease burden in India. Lancet Reg Health SE Asia. 2023.
  3. Zymlinski R et al. High-sensitivity troponin and outcomes. Int J Cardiol. 2017.