Correlation of Bedside ICU Monitor–Derived Computerized QT and QTc Measurements with Standard 12-Lead ECG Measurements

Objectives: Prolongation of the QT/QTc interval is associated with an increased risk of torsade de pointes. Although obtaining a standard 12-lead ECG is common for this evaluation in pediatric cardiac intensive care unit (CICU) patients, it may interrupt patient care or increase staff workload. Continuous QT/QTc measurements can be performed using bedside monitors with dedicated software in the pediatric CICU. This study aimed to evaluate the agreement between computerized QT/QTc measurements obtained from bedside monitors (three leads) and time-matched standard 12-lead ECGs.
Methods: This study was designed as a retrospective observational study. QT/QTc measurements were obtained using convenience sampling, with both ECG types recorded within ≤30 minutes of each other. Agreement between the two methods was assessed using Bland–Altman analysis.
Results: During the study period, 100 patients had both bedside monitor and 12-lead ECG measurements compared. For QT measurements, the mean bias difference was not statistically significant (β=−1.9, 95% CI=4, −11.05; p=0.6; limits of agreement [LOA]=−60, 54). For QTc measurements, the mean bias difference was also not statistically significant (β=−3.20, 95% CI=4, −11.05; p=0.6; LOA=−65, 57).
Conclusion: There was good agreement between the two methods for both QT and QTc measurements. Bedside monitor QT/QTc assessments may help identify patients at risk.

Keywords: Electrocardiography, intensive care, QTc