CLINICAL UTILITY OF CARDIAC TROPONIN I IN THE EARLY DIAGNOSIS OF ACUTE MYOCARDIAL INFARCTION

Abstract

Acute myocardial infarction continues to be a maJor public health problem all over the world. More than 60% of deaths associated with AMI occur within one hour of the event. Early thrombolytic intervention gives great promise to AMI patients and decreases the mortality rate from 30 % to less than 6%. Diagnosis of AMI, based on WHO criteria, includes a clinical history of chest pain, typical ECG changes, and serial changes of cardiac enzymes. The diagnosis of AMI as formerly established by WHO requires at least two of the previous criteria. As chest pain is a variable symptom and initial ECG is diagnostic in about 50% of cases only, hence biochemical markers have gained extreme importance in the early diagnosis of AMI. Creatine kinase and its isoenzyme MB are currently considered the main marker for diagnosing AMI because of the characteristic rise and fall in enzyme activity on serial ' measurements, which is nearly pathognomonic to AMI. CK- MB has a diagnostic sensitivity of about 50% three hours after infarction, and 90% six hours after infarction. However, its cardiospecificity is far from complete.