CORRELATION OF CORRECTED QT INTERVAL WITH QUANTITATIVE CARDIAC TROPONIN-I LEVELS AND ITS PROGNOSTIC ROLE IN NON ST ELEVATION MYOCARDIAL INFARCTION

Background:There is a large body of evidence of specific myocardial injury markers such as cardiac troponin I (cTnI) and cardiac troponin T (?TnT) for short and long-term prognostic values of NSTE-ACS mortality and new infarction.Objective: The present study was conducted to assess the correlation between corrected QT interval with cardiac troponin-I levels in NSTE-MI patients and to assess if prolonged corrected QT interval independently predicts higher 30-day Major Adverse Cardiac Events (MACE) in NSTE-MI patients. Material and Method: we enrolled 301 patients with the diagnosis of NSTEMI. Demographic variables at admission were age, gender, arterial pressure, history of CAD, hypertension, diabetes mellitus, smoking, dyslipidemia, previous coronary revascularization, and medication before entering the study. All patients were classified at admission according to the TIMI score for NSTE-ACS.Cardiac troponin I was measured in all cases with the sample collected 24 hr after the beginning of last angina episode. Concentrations ≥ 0.01 ng/ml were considered to be positive. A second measurement was done after 12 h in patients in whom the first determination is negative.Corrected QT interval(longest) measurement was done according to American Heart association guidelines. Patients were treated as per protocol. Major adverse cardiovascular events (includes, death due to cardiovascular cause, Non-fatal Myocardial Infarction and Recurrent Unstable Angina and ensuing urgent revascularization.) that were observed up to 30 days post discharge.Results: Troponin-I values and QTc interval was significantly higher in patients with diabetes and dyslipidemia, who presented with higher TIMI scores, severe LV systolic dysfunction ,higher killip class and hypotension and with multivessel disease, did not differ significantly according to culprit vessel. There was significant correlation with coefficient of 0.637 between QTc-max and Troponin I.Patients with MACE had significantly higher mean Troponin - I and mean QTc interval.Conclusion: Corrected QT interval has a strongly positive significant correlation with quantitative troponin I level in NSTEMI patients and Prolonged corrected QT interval is independently predictive of higher rate of major adverse cardiovascular events after NSTEMI within 30 days post discharge.