Incidence and predictors of QT interval prolongation in the intensive care units of a tertiary pulmonary center

Abstract

Introduction: Critically ill patients are more prone to prolongation of QT interval (QT) because of the severity of illness and medication complexity. Aims: We aimed to determine the rate and risk factors of corrected QT interval (QTc) prolongation in the intensive care unit (ICU) patients. Methods: A prospective observational study was conducted for six months. The patients above 18 years old admitted to the ICUs (medical, surgical, emergency) of a pulmonary referral center included in the study. All patients were evaluated with a 12-lead electrocardiogram (ECG) on day 1, 3 and 5 of admission. Baseline demographics, past medical history, current medical diagnosis, concomitant medications, laboratory data, heart rate, and QTc were collected for each patient. QTc >460 ms in male and >470 ms in female or increase >60ms above baseline was defined as prolonged QTc. The relationship between QTc prolongation and its predictors was examined using logistic regression models. Results: One hundred three consecutive patients (61.1±17.8 years; 60.2% male; baseline QTc 408.5±32.1 ms) were evaluated. Diseases of the respiratory system (39.8%) and neoplasms (16.5%) were the most common primary diagnosis. The rate of QTc prolongation was 23% within 5 days of ICU admission. Male sex (OR 6.6, CI 1.2-35.7), administration of azithromycin (OR 13.2, CI 1.2-142.0) and amiodarone (OR 5.5, CI 1.0-29.9) were associated with an increased risk of QTc prolongation (p Conclusions: Prolongation of QTc are common among ICU admitted patients. Increased vigilance in male patients and patients receiving azithromycin or amiodarone is warranted to prevent the consequences of QTc prolongation.