Professor and Dean College of Veterinary Medicine, University of Illinois Urbana-Champaign Urbana, IL, United States
Abstract:
Background: Small but consistent differences exist for human electrocardiogram (ECG) measurements obtained using digital electrocardiographs and their associated computer-based analysis programs. We hypothesized that more substantive measurement differences exist between digital electrocardiographs when computer-based ECG measurements, using software designed and optimized to analyze human ECGs, are obtained from dogs.
Objectives: To compare measured ECG intervals and amplitudes using a new wireless veterinary electrocardiograph (VET-ECG, Dextronix Inc) to those obtained using a reference electrocardiograph designed for human use (Pagewriter XLi M1790A, Hewlett-Packard Co). To complete a methods comparison study to develop ECG reference intervals for endurance-trained dogs using the new wireless electrocardiograph. Animals: Convenience sample of 122 healthy endurance trained sled dogs.
Methods: Six-lead ECG recordings (leads I, II, III, aVR, aVL, aVF) were obtained simultaneously using wireless and reference electrocardiographs with dogs in right lateral recumbency. Measurements for the two electrocardiographs were compared using Wilcoxon’s signed-rank test, Deming regression, and Bland-Altman plots.
Results: Differences (P < 0.001) were identified in measured median values between wireless and reference electrocardiographs for global ECG intervals and durations, and most lead amplitudes. The differences, expressed as a percentage of the reference electrocardiograph median value, were P-wave duration (-15.3%), PQ interval (-10.0%), QRS duration (-6.5%), QT interval (-20.2%), and lead II P-(-3.0%), Q-(+3.9%), R-(+15.6%), and T-wave (+21.2%) amplitude. Conclusions and clinical importance: Clinically significant differences in computer-based measurements were identified when dog ECGs were obtained using two digital electrocardiographs. Reference intervals for dog ECGs may differ depending on the electrocardiograph and its computer-based analysis program.
