title: Automated measurements for individualized heart rate correction of the QT interval.
abstract: BACKGROUND
  Subject-specific electrocardiographic QT interval correction for heart rate is often used in clinical trials with frequent electrocardiographic recordings. However, in these studies relatively few 10-s, 12-lead electrocardiograms may be available for calculating the individual correction. Highly automated QT and RR measurement tools have made it practical to measure electrocardiographic intervals on large volumes of continuous electrocardiogram data. The purpose of this study was to determine whether an automated method can be used in lieu of a manual method.
  
  
  METHODS
  In 49 subjects who completed all treatments in a four-armed crossover study we compared two methods for derivation of individualized rate-correction coefficients: manual measurement on 10-s electrocardiograms and automated measurement of QT and RR during continuous 24-h electrocardiogram recordings. The four treatments, received by each subject in a latin-square randomization sequence were placebo, moxifloxacin, and two doses of an investigational drug.
  
  
  RESULTS
  Analysis of continuous electrocardiogram data yielded a lower standard deviation of QT:RR regression values than the manual method, though the differences were not statistically significant. The within-subject and within-treatment coefficients of variation between the manual and automated methods were not significantly different. Corrected QT values from the two methods had similar rates of true and false positive identification of moxifloxacin's QT prolonging effect.
  
  
  CONCLUSIONS
  An automated method for individualized rate correction applied to continuous electrocardiogram data could be advantageous in clinical trials, as the automated method is simpler, is based upon a much larger volume of data, yields similar results, and requires no human over-reading of the measurements.
authors.affiliation: Cardiology Division, Department of Medicine, The University of Utah, Salt Lake City, UT, USA jmason12@charter.net.
authors.forename: Jay W
authors.initials: JW
authors.lastname: Mason
authors.affiliation: Tarizona eHealth Services, San Carlos, CA, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Moon
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects; D018592:Cross-Over Studies; D004562:Electrocardiography; D024841:Fluoroquinolones / Q000009:adverse effects; D006339:Heart Rate; D006801:Humans; D000077266:Moxifloxacin; D012107:Research Design
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D000077266:Moxifloxacin
keywords: QT interval; QTcI; heart rate correction