ACUTE MYOCARDIAL INFARCTION;

A cross sectional study to find out the predictive value of creatine kinase-MB (CK-MB), cardiac troponin T (CTnT) and cardiac troponin I (CTnI) as preferred serum marker

Abstract

A delay in confirming a diagnosis of AMI may increase the risk of complication and a delay in ruling out the diagnosis
contributes to overcrowding in the emergency department. A crucial step in confirming or ruling out the diagnosis of AMI is the
measurement of myocardial enzymes in the serum. Early administration of thrombolytic therapy results in improved survival after AMI. So
this study was planned to find out the serum marker with a better predictive value for the identification of acute myocardial infarction at the
time of admission. Design: Cross-sectional study. Setting: Emergency department of Punjab Institute of Cardiology, Lahore. Period:
15th May, 2008 to 15th July, 2008. Methods: The study population consisted of 70 patients. Patients from both sexes, with clinical
history of typical chest pain for more than 30 minutes in duration with evidence of acute changes of myocardial infarction on ECG were
included in the study. This study was conducted to compare the positive predictive value and negative predictive value of creatine kinase-
MB (CK-MB), cardiac troponin T (CTnT) and cardiac troponin I (CTnI) for detection of AMI. Data analysis was performed with Statistical
Package for Social Sciences 11.5 (SPSS 11.5). Results: 88.6% cases had CTnI concentration more than the limit value while 11.4%
cases had CTnI less than the limit value. The concentration of CTnT was more than the limit value in 70% cases and below the limit value in
30% cases. The concentration of CK-MB was more than the limit value in 35.7% cases and 64.3% cases had CK-MB value less than the
limit value. The positive predictive value (PPV) of CtnI is 100% and negative predictive value (NPV) of CTnT is 100% in this study.
Conclusions: It is concluded that CTnl is the better marker for the identification of acute myocardial infarction and CTnT is the better
marker to exclude AMI as compared to CK-MB.