Serial kinetics and diagnostic interrelationships of cardiac biomarkers in acute myocardial infarction

Abstract

Background:
Acute myocardial infarction (AMI) is a major cause of morbidity and mortality worldwide. Cardiac biomarkers are essential for diagnosis and monitoring of AMI. Although cardiac troponin T (cTnT) is the preferred biomarker, enzymes such as creatine phosphokinase-MB (CPK-MB), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) are still widely used, especially in resource-limited settings.

Objectives:
To evaluate the serial kinetics, absolute and percentage delta changes, and interrelationships of cTnT, CPK-MB, AST, and LDH during the first 48 hours after admission in patients with AMI, and to explore their complementary diagnostic roles in a resource-limited healthcare setting.

Patients and Methods:This hospital-based observational study included 50 patients with confirmed AMI and 50 age- and sex-matched healthy controls. Serial blood samples were collected from AMI patients at 0, 6, 12, 24, 36, and 48 hours after admission. Biomarker levels were measured using standard laboratory methods. Absolute and percentage delta changes were calculated relative to controls. Pearson’s correlation coefficient was used to assess relationships between biomarkers at each time point.

Results:All biomarkers were significantly elevated in AMI patients compared with controls. cTnT showed a progressive and sustained rise, reaching over 1100% above control values at 48 hours. CPK-MB and AST demonstrated earlier peaks around 24 hours followed by partial decline, while LDH showed a delayed but marked rise. Most biomarker pairs showed no significant linear correlation at any time point; weak negative correlations observed at 12 hours were small in magnitude and likely of limited clinical significance.

Conclusion:Cardiac biomarkers in AMI exhibit distinct temporal kinetics with minimal linear correlation.Lack of correlation should not be interpreted as lack of diagnostic utility; rather, it highlights that biomarkers reflect different pathophysiological phases of myocardial injury. cTnT remains the most reliable biomarker, while CPK-MB, AST, and LDH should be interpreted as complementary rather than interchangeable markers.

Received 16 December 2025

Accepted 18 January 2026

Published 28 April 2026