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Updated: Jul 10, 2026
Hemodynamic Precision in the Neonatal Intensive Care Unit using Targeted Neonatal Echocardiography
Published on: January 27, 2023
An algorithm for QT interval monitoring in neonatal intensive care units
Eric D Helfenbein1, Michael J Ackerman, Pentti M Rautaharju
1Advanced Algorithm Research Center, Philips Medical Systems, Milpitas, CA, USA. eric.helfenbein@philips.com
Insights
Automated continuous QT interval monitoring is feasible and accurate for neonatal patients, even with challenging ECG signals. This technology can help identify vulnerable infants early.
Area of Science:
- Biomedical Engineering
- Pediatric Cardiology
- Neonatal Intensive Care
Background:
- QT surveillance is crucial for neonates due to potential QT-prolonging medications and hereditary long-QT syndrome, a factor in sudden infant death syndrome.
- Automated continuous QT monitoring in neonates is challenging due to high heart rates, ECG signal quality issues, and limited leads.
Purpose of the Study:
- To enhance and evaluate an automated QT interval monitoring algorithm for neonatal and pediatric patients.
- To assess the feasibility and accuracy of the algorithm in a neonatal intensive care unit setting.
Main Methods:
- An enhanced automated QT interval monitoring algorithm was developed, incorporating specific adjustments for high heart rates and neonatal ECG characteristics.
- Sixty-six neonatal ECG recordings from two major US teaching hospitals were used for algorithm evaluation, divided into training (TRN) and testing (TST) datasets.
- Algorithm accuracy was assessed by comparing its measurements to manual annotations by two cardiologists using mean error, regression slope, and correlation coefficients.
Main Results:
- The algorithm successfully measured approximately 80% of the studied ECGs, despite technical challenges with noisy recordings.
- Low mean and standard deviation of error were observed (TRN = -3 ± 8 ms; TST = 1 ± 20 ms).
- High regression slopes (TRN = 0.94; TST = 0.83) and correlation coefficients (TRN = 0.96; TST = 0.85) indicated good algorithm accuracy.
Conclusions:
- Automated continuous QT interval monitoring is feasible and accurate in the neonatal intensive care setting.
- This technology holds potential for earlier recognition of "vulnerable" infants requiring closer monitoring.
- Further refinement may improve performance on challenging ECG cases.
Abstract:
QT surveillance of neonatal patients, and especially premature infants, may be important because of the potential for concomitant exposure to QT-prolonging medications and because of the possibility that they may have hereditary QT prolongation (long-QT syndrome), which is implicated in the pathogenesis of approximately 10% of sudden infant death syndrome. In-hospital automated continuous QT interval monitoring for neonatal and pediatric patients may be beneficial but is difficult because of high heart rates; inverted, biphasic, or low-amplitude T waves; noisy signal; and a limited number of electrocardiogram (ECG) leads available. Based on our previous work on an automated adult QT interval monitoring algorithm, we further enhanced and expanded the algorithm for application in the neonatal and pediatric patient population. This article presents results from evaluation of the new algorithm in neonatal patients. Neonatal-monitoring ECGs (n = 66; admission age range, birth to 2 weeks) were collected from the neonatal intensive care unit in 2 major teaching hospitals in the United States. Each digital recording was at least 10 minutes in length with a sampling rate of 500 samples per second. Special handling of high heart rate was implemented, and threshold values were adjusted specifically for neonatal ECG. The ECGs studied were divided into a development/training ECG data set (TRN), with 24 recordings from hospital 1, and a testing data set (TST), with 42 recordings composed of cases from both hospital 1 (n = 16) and hospital 2 (n = 26). Each ECG recording was manually annotated for QT interval in a 15-second period by 2 cardiologists. Mean and standard deviation of the difference (algorithm minus cardiologist), regression slope, and correlation coefficient were used to describe algorithm accuracy. Considering the technical problems due to noisy recordings, a high fraction (approximately 80%) of the ECGs studied were measurable by the algorithm. Mean and standard deviation of the error were both low (TRN = -3 +/- 8 milliseconds; TST = 1 +/- 20 milliseconds); regression slope (TRN = 0.94; TST = 0.83) and correlation coefficients (TRN = 0.96; TST = 0.85) (P < .0001) were fairly high. Performance on the TST was similar to that on the TRN with the exception of 2 cases. These results confirm that automated continuous QT interval monitoring in the neonatal intensive care setting is feasible and accurate and may lead to earlier recognition of the "vulnerable" infant.
