Assessment of the prevalence and associated risk factors of QT prolongation, with a focus on medication use, among patients with cardiovascular disease referred to Shahid Chamran Heart Hospital

Given the importance of LQTS and its association with potentially fatal ventricular arrhythmias, assessing its prevalence across diverse populations is crucial. This study aims to determine the prevalence of LQTS and its associated risk factors among patients with cardiovascular disease admitted to a heart hospital in Iran, particularly focusing on medication use. Upon arrival at the emergency department, all patients were evaluated, and relevant data, including medication use, past medical history, and laboratory test results, were extracted from their medical records. Additionally, a 12-lead ECG was obtained from each patient at admission. In this study, the QT interval was reported using the Hodges formulas. QTc thresholds were defined according to both the 2009 AHA/ACCF/HRS guideline and the 99th percentile reference values. A total of 371 individuals presenting to the emergency department of Shahid Chamran Heart Hospital were included in this study. According to the 2009 guideline, 64 (17.25%) patients were diagnosed with LQTS, and, using the Hodges formula and considering the 99th percentile cutoff, 31 (8.35%) had QT intervals above the 99th percentile. Out of 64 patients diagnosed with LQTS, 27 (42.18%) were using QT-prolonging medications. Furthermore, a significant correlation was observed between medication use and the incidence of LQTS. The prevalence of LQTS observed in the present study was slightly higher than in other studies, which may be attributed to the selection of a cardiac patient population. A significant correlation was observed between medication use and the incidence of LQTS.