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.

Management of Asymptomatic Wolff-Parkinson-White Pattern by Pediatric Electrophysiologists.

OBJECTIVE: To determine the present-day approach of pediatric cardiac electrophysiologists to asymptomatic Wolff-Parkinson-White (WPW) pattern and to contrast to both published consensus statements and a similar survey. STUDY DESIGN: A questionnaire was sent to 266 Pediatric and Congenital Electrophysiology Society physician members in 25 countries; 21 questions from the 2003 survey were repeated, with new questions added regarding risk stratification and decision making. RESULTS: We received 113 responses from 13 countries, with responders having extensive electrophysiology experience (median 15 years [IQR 8.5-25 years]). Only 12 (11%) believed that intermittent pre-excitation and 37 (33%) that sudden loss of pre-excitation on exercise test were sufficient evidence of accessory pathway safety to avoid an invasive electrophysiology study. Optimal weight for electrophysiology study was 20 kg (IQR 18-22.5 kg), and 61% and 58% would then ablate all right-sided or left-sided accessory pathways, respectively, regardless of electrophysiological properties, whereas only 23% would ablate all septal accessory pathways (P < .001). Compared with 2003, respondents were more likely to consider inducible arrhythmia (77% vs 26%, P < .001) as sufficient indication alone for ablation. CONCLUSIONS: In the context of recent literature regarding the reliability of risk-stratification tools, most operators are now performing electrophysiology study for asymptomatic Wolff-Parkinson-White regardless of noninvasive findings. Many will then proceed to default ablation of all accessory pathways distant from critical conduction structures.

Do pediatric electrophysiologists read pre-participation screening electrocardiograms more accurately than general pediatric cardiologists?

Pre-participation electrocardiogram (ECG) screening of athletes is controversial. Pediatric electrophysiologists do not interpret screening ECGs more accurately than pediatric cardiologists with average number of correct ECG interpretations of 13.1-12.4 (P = .14). Electrophysiologists ordered fewer follow-up tests and were more likely to give sports recommendations based on published guidelines.