The relationship between corrected QT interval and neutrophil to lymphocyte ratio in patients with acute coronary syndrome

Background/Aim: In recent years, prolonged corrected QT (QTc) interval is thought to be an independent risk factor in patients with Acute Coronary Syndrome (ACS). Our aim in this study is to determine whether there is a relationship between the Neutrophil/Lymphocyte Ratio (NLR), which is a new inflammatory parameter, and prolonged QTc corrected (QTc) interval in patients with ACS. Methods: In a retrospective cohort study, 649 patients with ACS were enrolled from January 2017 to July 2019, out of which ninety-two patients died during follow-up. Patients were divided into two groups according to the prolonged QTc interval (QTc ≥450 msec). The relationship between QTc interval prolongation and NLR was evaluated. The primary endpoint was early all-cause death. Results: Thirty-one of 135 patients (22.9% P=0.002) with QTc interval prolongation and 61 of 514 patients without QTc prolongation (11.8% P=0.002) died. Prolonged QTc interval was positively correlated with NLR (r=0.20, P=0.001). Both NLR (OR: 1,016; 95% CI: 1.004–1.028; P=0.01) and QTc interval (OR: 1.016; 95% CI: 1.004–1.028; P=0.006) independently predicted early mortality. In the ROC curve analysis, the AUC value of QTc interval to predict in-hospital mortality was 0.680 (95% CI: 0.597-0.763; P=0.001), with a sensitivity of 35%, a specificity of 82% and an optimum cut-off value of ≥450 msec. The AUC value of NLR to predict in-hospital mortality was 0.711 (95% CI: 0.653-0.769; P<0.001), with a sensitivity of 64%, a specificity of 68% and an optimum cut-off value of ≥3.9. Conclusion: In this study, we showed that prolonged QTc interval was positively associated with NLR, which is an indicator of systemic inflammation in patients with ACS, for the first time. Also, QTc interval prolongation and increased NLR were independent predictors of early mortality.