Related Experiment Video
Updated: Mar 7, 2026
Electrocardiogram Recordings in Anesthetized Mice using Lead II
Published on: June 20, 2020
Mid-Term Follow-up of School-Aged Children With Borderline Long QT Interval
Aya Miyazaki1, Heima Sakaguchi1, Yu Matsumura1
1Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center.
Insights
Children with borderline long QT syndrome (b-LQT) require ongoing monitoring, as their LQTS score and corrected QT interval (QTc) can change. A low LQTS score suggests a lower risk, but continued follow-up is recommended for b-LQT evaluation.
Area of Science:
- Pediatric Cardiology
- Clinical Electrophysiology
- Genetics
Background:
- Definitive diagnostic criteria and follow-up strategies for borderline long QT syndrome (b-LQT) in children are lacking.
- b-LQT is defined as a corrected QT interval (QTc) between 400-500 ms.
Purpose of the Study:
- To retrospectively evaluate the clinical course, genetic testing, and QTc changes in school-aged children with b-LQT.
- To assess the utility of the LQTS score in managing pediatric b-LQT patients.
Main Methods:
- Retrospective analysis of 59 school-aged children (5-18 years) with b-LQT.
- Evaluation of clinical events, genetic testing, QTc measurements, and LQTS scores during a mean follow-up of 6 years.
Main Results:
- Two patients experienced syncope; no aborted cardiac arrests or sudden cardiac deaths occurred.
- Positive genetic testing rates varied by LQTS probability (92% high, 57% intermediate, 67% low).
- Maximum and mean QTc values differed significantly across LQTS probability categories; QTc at rest and recovery changed, altering LQTS probability in 50% of patients.
Conclusions:
- The LQTS score is a useful tool for evaluating pediatric b-LQT, with low scores indicating low cardiac event risk.
- LQTS scores and QTc can change during follow-up, necessitating continued monitoring for b-LQT.
- Clear guidelines for b-LQT follow-up are needed.
Background:
There are no definitive diagnostic criteria or follow-up strategies for long QT syndrome (LQTS) in children with a borderline long QT interval (b-LQT).
Methods And Results:
We retrospectively evaluated the clinical course, genetic testing results, corrected QT interval (QTc), and LQTS score of 59 school-aged children (5-18 years old) with a b-LQT (400≤QTc<500 ms). Syncope, but neither aborted cardiac arrest nor sudden cardiac death, occurred in 2 patients during the follow-up (6±3.4 years) with LQTS scores ≥4.5 points. The genetic testing results were positive in 92%, 57%, and 67% of patients with high, intermediate, and low probabilities of LQTS, respectively. The maximum and mean QTc during the follow-up significantly differed among the categories with a probability of LQTS, but not the minimum QTc. However, the QTc at rest and at the recovery point after exercise stress testing dramatically changed at the last follow-up. Consequently, the probability of LQTS changed in half of the patients.
Conclusions:
The LQTS score is a reasonable indicator for evaluating school-aged children with a b-LQT, and patients with a low LQTS score appear to be at low risk for cardiac events. However, the LQTS score can change during follow-up. Therefore, when there is doubt or concern for patients with a b-LQT, it is preferable to continue following them. Guidelines on follow-up strategies are desired for b-LQT.
More Related Videos
08:28Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus
Published on: April 5, 2011
13:08Measurement of Fronto-limbic Activity Using an Emotional Oddball Task in Children with Familial High Risk for Schizophrenia
Published on: December 2, 2015
Related Concept Videos
01:26Longitudinal Studies
02:20Longitudinal Research
01:30Dysrhythmias V: Evaluating Dysrhythmias
01:30Oppositional Defiant Disorder
Diagnostic Criteria and...