QTc Prolongation and Risk of Torsades de Pointes in Hospitalized Pediatric Oncology Patients.

Objective To evaluate the prevalence of torsades de pointes and to identify risk factors associated with QTc prolongation of >= 500 milliseconds in hospitalized pediatric oncology patients. A QTc prolongation of >= 500 milliseconds is associated with higher mortality in hospitalized adults but has not been demonstrated in pediatrics. Study design A single-center, retrospective review of all hospitalized oncology patients <= 21 years of age was performed from 2014 to 2016. Patients with long/short QT syndrome or a QRS interval of >= 120 ms were excluded. Rapid response events were reviewed to determine the prevalence of torsades. In patients with ECGs for review, data were compared between patients with a QTc of <500 and >= 500 ms via logistic regression. Results There were 1934 hospitalized patients included. Rapid response events occurred in 90 patients (4.7%) with 2 torsades events (0.1%). There were 1412 electrocardiograms performed in 287 unique patients (10.6 +/- 6.3 years of age; 43% female). The mean QTc was 448 +/- 31 ms; 25 patients (8.7%) had >= 1 ECG with a QTc of >= 500 ms. The prevalence of torsades was greater in patients with a QTc of >= 500 ms (8% vs 0%; P<.01). In multivariate analysis, factors associated with a QTc of >= 500 ms included female sex, (OR 2.95) and >= 2 QT-prolonging medications (OR, 2.95). Conclusions The prevalence of torsades in hospitalized pediatric oncology patients was low (0.1%), although the risk was significantly greater in patients with a QTc of >= 500 ms. Routine monitoring of electrocardiograms and electrolytes is essential in patients with risk factors predisposing to QTc prolongation.