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Limb lead interchange in thorough QT/QTc studies

Vaibhav Salvi1, Dilip R Karnad, Gopi Krishna Panicker

  • 1Quintiles Cardiac Safety Services, 502 A, Leela Business Park, M.V. Road, Andheri (East), Mumbai 400 059, India. vaibhav.salvi@quintiles.com

Journal of Clinical Pharmacology
|January 7, 2011
PubMed

Insights

Electrocardiogram (ECG) limb lead interchanges occurred in 17.9% of subjects, more often with Holter devices. Quality control is crucial for accurate QT interval measurements and diagnosis.

Area of Science:

  • Cardiology
  • Medical Device Technology
  • Clinical Diagnostics

Background:

  • Electrocardiograms (ECGs) are vital for cardiac assessment.
  • Limb lead interchanges are a known source of ECG artifact.
  • Thorough QT/QTc studies require high-fidelity ECG data.

Purpose of the Study:

  • To quantify the incidence and types of inadvertent limb lead interchanges in clinical studies.
  • To evaluate the effectiveness of different methods in identifying these interchanges.
  • To assess the impact of limb lead interchanges on QT interval measurement and diagnosis.

Main Methods:

  • Analysis of 85,133 ECGs from 484 subjects across 5 thorough QT/QTc studies.
  • Utilized a dedicated quality control process in a central ECG laboratory.
  • Compared identification rates between ECG devices, experienced readers, and quality control.

Main Results:

  • Limb lead interchanges were found in 3.4% of ECGs (17.9% of subjects).
  • Holter devices showed significantly higher interchange rates (7.5%) than 12-lead ECGs (0.8%).
  • Experienced readers identified 79% of interchanges, with 21% detected solely by quality control.

Conclusions:

  • Limb lead interchanges are a common issue in ECG acquisition, particularly with Holter monitors.
  • Dedicated quality control processes are essential for accurate ECG interpretation.
  • Undiagnosed interchanges can lead to erroneous QT interval measurements and misdiagnosis.

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