title: Electrocardiographic data quality in thorough QT/QTc studies.
abstract: BACKGROUND
  Most drugs with systemic bioavailability have to undergo a thorough QT (TQT) study, which includes a pharmacologic positive control. A set of QTc-quality tests was recently proposed with the possible aim of removing the need for a positive control.
  
  
  OBJECTIVE
  We evaluated the influence of QT measurement and QTc computation methodology on the proposed QTc-quality tests.
  
  
  METHODS
  The baseline ECG waveforms and fiducial points were retrieved from 34 crossover TQT studies that had full-day baseline ECGs prior to each study period. The QT measurement methodology and recorder type were retrieved from study reports. The influence of QTc computation methodology was investigated by applying the pattern-matching technique and/or using the 10-s average heart rate.
  
  
  RESULTS
  There were no statistical differences in any QTc-quality test values between studies using continuous or 10-s bedside recordings and, in a subset of the quality test, an increase of data quality for semi-automatically read studies compared with those manually read (p < 0.01). There was a significant improvement (p < 0.01) in all the QTc-quality test values for QTc measurements obtained by using pattern matching with or without 10-s average heart rate in comparison to the original QTc measurements.
  
  
  CONCLUSIONS
  The findings suggest that QTc quality is mostly driven by the QTc measurement methodology rather than other study-related factors.
authors.affiliation: Division of Pharmacometrics, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, US FDA, Silver Spring, MD, USA, lars.johannesen@fda.hhs.gov.
authors.forename: Lars
authors.initials: L
authors.lastname: Johannesen
authors.forename: Christine
authors.initials: C
authors.lastname: Garnett
authors.forename: Marek
authors.initials: M
authors.lastname: Malik
mesh_terms: D064420:Drug-Related Side Effects and Adverse Reactions; D004562:Electrocardiography / Q000592:standards*; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008297:Male