Assessment of serum cardiac troponin-I over serum CPK-MB in early diagnosis of acute myocardial infarction (AMI)

ABSTRACT

Background: The early mortality rate from AMI is 30% with about half of them occurring within 1hour of disability. Although the mortality rate after admission for AMI has declined by 30% over the past decades, approximately 1 of every 25 patients who survive the initial hospitalization die in the first year after AMI. The gold standard for diagnosis of MI has been an elevated serum level of creatinine kinase – myocardial band (CK- MB), the cardiac-specific isoenzyme of CK. However, elevated CK-MB may not detect all myocardial necrosis. In patients who die suddenly after severe or silent episodes of ischemia, autopsies frequently reveal micronecrosis that was not reflected in routine CK-MB measurements. The present study was undertaken to know that serum Cardiac Troponin-I is more sensitive marker than serum CPK-MB in early diagnosis of acute myocardial infarction (AMI).Methods: The study was carried out in tertiary care hospital in Gulbarga. The study was undertaken with an aim to study that serum cardiac troponin-I (cTnl) is more sensitive than serum CK-MB in early diagnosis of acute myocardial infarction (AMI). The study was conducted on patients admitted with history of chest pain suggestive of AMI as diagnosed by WHO criteria to medicine ward of Basaveshwar Teaching and General Hospital, Gulbarga. The period of study was from June 2012 to June 2014. The sample size included 100 patients with history of chest pain suggestive of AMI, selected by simple random method.Results: Our results revealed that cardiac troponin I was more sensitive (62%) than CK-MB in overall cases admitted in between 6-24 hrs from the onset of chest pain. Maximum number (41%) of AMI patients were affected on the anterior wall followed by Inferior wall of AMI. 11 percent were affected with Antero lateral wall wereas 5 to 6 percent were affected with anteroseptal and global acute and right ventricular AMI was seen among 2 percent of patients. Anterior wall AMI was the significantly affected site with AMI (ʎ212.5, P0.0004). The maximum number of acute myocardial infarctions were ST elevation myocardial infarctions. 28% of cases where CKMB is normal, the cTnI detects the AMI cases indicating its sensitivity.Conclusions: Cardiac troponin-I (cTnI) was more sensitive serum marker than CKMB in the early diagnosis of acute myocardial infarction (AMI). Anterior wall was the most significantly affected site of AMI. In the future, further improvements in analytical performance may open additional diagnostic windows