Relationship between a Prolonged Corrected QT Interval and Mortality in Patients Presenting with Syncope at the Emergency Department

Abstract

Background. Syncope is a common symptom in emergency department patients. Among various etiological factors, cardiac causes have the highest risk of mortality. The corrected QT interval is considered an independent predictor of mortality for many diseases. Objectives. Analyze QT interval analysis of patients presenting to the emergency department with syncope. Methods. In this prospective observational study, patients who presented to the emergency department with syncope between January 1, 2018, and January 1, 2019 were included. Results. The median age was 64 (49-78) years, and 58.8% of patients were male. The corrected QT interval (QTc) in patients with coronary artery disease and chronic obstructive pulmonary disease was longer than those without. There was no statistically significant association between hypertension, diabetes, stroke, thyroid disease, and prolonged QTc. Patients who did not survive had significantly prolonged QT intervals. According to ROC analysis, sensitivity of >440.5 ms QTc values in predicting mortality was 86% and specificity was 71% ( $\text{AUC}=0.815$ ; $95\%\text{CI}=0.71-0.91$ ; $p<0.001$ ). Conclusions. Patients admitted to emergency department with syncope and a prolonged QTc are associated with a higher mortality rate and thus can provide us with an important guide for the management of these patients.