Utility of the QT interval in predicting outcomes in patients presenting to the emergency department with chest pain

OBJECTIVES: The aim of this study was to investigate whether prolongation of the heart rate-corrected QT interval (QTc) is an independent risk factor for predicting future acute coronary syndrome (ACS) occurrence or mortality in patients with at least one cardiac risk factor presenting with chest pain to the emergency department (ED). METHODS: This is a single-center, retrospective study of patients presenting with chest pain to the ED of Einstein Medical Center, Philadelphia, between 2011 and 2012. Proportional hazards models were used to calculate hazard ratios (HRs) for occurrence of ACS or death within 1 year. Kaplan-Meier curves were used to determine the time to event for QTc low (< 460 ms) versus QTc high (≥ 460 ms) groups. RESULTS: A total of 595 patients met the inclusion criteria. Older age, hypertension, diabetes mellitus, and hyperlipidemia were more common in the QTc high group. Patients in the QTc high group were more likely to experience subsequent ACS or death (HR 8.12, 95% confidence interval 4.00-16.72), even after adjusting for traditional cardiac risk factors (HR 7.68, 95% confidence interval 3.57-16.61). CONCLUSION: QTc prolongation at ED presentation with chest pain and at least one cardiac risk factor predicts subsequent ACS and death.