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Universal Correction for QT/RR Hysteresis.

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Clinical pharmacology QT/QTc studies can be smaller by using a QT/RR hysteresis model, which corrects for heart rate variability. This model is universally applicable and reduces QTc variability in healthy subjects.

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Area of Science:

  • Clinical Pharmacology
  • Cardiology
  • Biomedical Data Science

Background:

  • Clinical pharmacology QT/QTc studies are crucial for drug safety evaluation.
  • Efficient data utilization can potentially reduce the size and cost of these studies.
  • Heart rate variability is a known confounder in QT interval measurements.

Purpose of the Study:

  • To investigate the impact of heart rate measurement on the accuracy of QTc data using large electrocardiogram (ECG) datasets.
  • To assess if supine positioning stabilizes heart rate in healthy subjects.
  • To evaluate if alternative heart rate measurements decrease QTc variability.

Main Methods:

  • Analysis of 80 thorough QT studies, including 747,912 ECGs from 6786 healthy subjects (Part I) and 897,570 ECGs from 751 healthy subjects (Part II).
  • Part I: Assessed heart rate stability in supine positions.
  • Part II: Applied a QT/RR hysteresis model for QTc correction using RR intervals.

Main Results:

  • Supine positioning did not consistently stabilize heart rate; instability exceeding 5 bpm occurred 40% of the time.
  • The QT/RR hysteresis model (95% adaptation in 120s) significantly reduced intra-subject QTc standard deviation.
  • Mean intra-subject QTc standard deviation was 7.14 ± 1.98 ms (women) and 6.38 ± 1.50 ms (men).

Conclusions:

  • A universally applicable QT/RR hysteresis model effectively minimizes QTc variability in healthy subjects.
  • Supine positioning is not a reliable method for stabilizing heart rate in clinical QT studies.
  • This model allows for the inclusion of variable heart rate episodes, potentially streamlining QT/QTc studies.