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Heart Rate Influence on the QT Variability Risk Factors
Irena Andršová1, Katerina Hnatkova2, Martina Šišáková1
1Department of Internal Medicine and Cardiology, University Hospital Brno, Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00 Brno, Czech Republic.
Diagnostics (Basel, Switzerland)
|December 19, 2020
Summary
QT variability index (QTVi) and standard deviation of QT interval durations (SDQT) are influenced by heart rate. SDQT is more reproducible and recommended over QTVi for QT interval variability analysis.
Area of Science:
- Cardiology
- Biomedical Engineering
- Physiology
Background:
- QT interval variability is used in risk diagnostics.
- Physiologic correlates of QT variability, especially in short ECGs, are under-researched.
Purpose of the Study:
- Investigate QT variability indices (QTVi, SDQT) in short ECGs.
- Relate these indices to heart rate and RR interval variability (SDRR).
Main Methods:
- Analysis of 657,287 10-second ECGs from 523 healthy subjects.
- Calculated QT variability indices (QTVi, SDQT) and SDRR.
- Statistical analysis of index relationships with heart rate and SDRR.
Main Results:
- Both QTVi and SDQT are significantly influenced by heart rate (p < 0.00001).
- QTVi exhibits poor intra-subject reproducibility (CV ~200%).
- SDQT shows stronger relation to heart rate than SDRR; QTVi is more influenced by heart rate and SDRR than SDQT.
Conclusions:
- SDQT is a more reliable measure of QT interval variability than QTVi.
- SDQT is preferable for future applications, particularly when combined with heart rate data.
Keywords:
QT variabilityQT variability indexRR variabilitysequential analysis of regression varianceunderlying heart rateMore Related Videos
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