Prognostic Value of Corrected QT Interval and its Correlation with Cardiac Troponin T in Non

Abstract

Background Presence of different risk groups in non-ST-elevation acute coronary syndrome (NSTE-ACS), indicate the need for new tools to perform early diagnosis and prognostic stratification. Thus, it has been shown that the corrected QT interval prolongation is an independent risk marker in NSTE-ACS with or without acute ischemic changes. However, there is scarce information about its relationship with other variables of known prognostic value, such as cardiac troponins. Objective The purpose of this study was to assess the correlation between the corrected QT interval prolongation and cardiac Troponin T in NSTE-ACS. Methods This prospective study included 106 patients admitted with NSTE-ACS. The corrected QT interval was measured on the admission ECG and at 6, 12, 18, 24, and 48 h. The cut-off point with best sensitivity and specificity to predict major clinical events was ³ 0.458 sec. Cardiac Troponin T ³ 0.04 ng/ml was considered positive. The composite end-point of cardiac death, non-fatal myocardial infarction and recurrent angina were the major clinical events up to 30 days after discharge. Patients were divided into two groups, according to the presence (group A) or absence (group B) of these events. Corrected QT interval on admission and maximum corrected QT interval were correlated with cardiac Troponin T in each group. Multivariate regression analysis was carried out to identify independent predictors of major clinical events. Results The correlation coefficient between cardiac Troponin T and maximum corrected QT interval was 0.38 (p <0.001) and maximum corrected QT ³ 0.458 sec was an independent predictor of major clinical events [OR=4.1 (IC 95% 1.7-11.2) p=0.002] with a negative predictive value of 80.8%. Conclusions Maximum corrected QT interval correlated with cardiac Troponin T values and was an independent predictor of risk in patients with NSTE-ACS.