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Updated: May 11, 2026
07:15
Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation
Published on: January 16, 2019
Do LQTS gene single nucleotide polymorphisms alter QTc intervals at rest and during exercise stress testing?
Peter F Aziz1, Tammy S Wieand, Jamie Ganley
1Cleveland Clinic Foundation, Department of Pediatric Cardiology and the Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA. azizp@ccf.org
Summary
Children with Long QT Syndrome genetic variants (LQT-PM) show longer QTc intervals during rest, exercise, and recovery compared to controls. Homozygous variants are linked to even longer resting QTc intervals.
Area of Science:
- Cardiology
- Genetics
- Pediatrics
Background:
- The effect of Long QT Syndrome genetic variants (LQT-PM) on cardiac repolarization during exercise and recovery is not well understood.
- QTc interval prolongation is a known risk factor for arrhythmias.
Purpose of the Study:
- To evaluate QTc interval adaptation during exercise stress testing (EST) in children with LQT-PM.
- To compare QTc interval adaptation in LQT-PM patients versus age- and gender-matched healthy controls.
Main Methods:
- 148 pediatric patients were divided into LQT-PM (43) and control (105) groups.
- All participants underwent a standardized exercise stress test with a 9-minute recovery period, including continuous ECG monitoring.
- QTc intervals were measured at rest, peak exercise, and during recovery phases.
Main Results:
- LQT-PM patients exhibited significantly longer QTc intervals at rest, peak exercise, and all recovery stages compared to controls.
- No abnormal QTc interval adaptation to exercise was observed in either group.
- Patients with homozygous LQT-PM SNPs had longer resting QTc intervals than those with heterozygous SNPs (435±23 ms vs. 415±20 ms, P<0.006).
Conclusions:
- Individuals with LQT-PM may present with prolonged QTc intervals across rest, exercise, and recovery phases.
- Homozygous LQT-PM genetic variants are associated with more pronounced resting QTc interval prolongation.
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