Two digital electrocardiographs and their computer-based analysis programs produce clinically significant differences in values and reference intervals for dog electrocardiograms.

ECG reference intervals and diagnostic thresholds are device-specific and should not be used interchangeably between different electrocardiographs.

This study compared ECG measurements obtained simultaneously from two digital electrocardiographs—one adapted for veterinary use and one for human use—in 121 adult endurance-trained sled dogs. Researchers evaluated nine global ECG indices and 15 lead-specific wave amplitudes using Wilcoxon signed-rank tests, Deming regression, and Bland-Altman plots. Clinically significant differences (defined as ≥10 ms for intervals or ≥10% for amplitudes) were identified primarily in Q- and R-wave amplitudes in leads II and III, where the veterinary electrocardiograph recorded values 11–23% higher than the human electrocardiograph. These differences had direct diagnostic implications: the veterinary device classified a greater proportion of dogs as potentially having left or right ventricular enlargement. Reference intervals derived from the two devices also differed, with the veterinary electrocardiograph producing narrower intervals for 7 of 9 global indices. The underlying cause appears related to differences in high-frequency (low-pass) filtering characteristics; the veterinary device attenuates higher frequencies to a lesser extent than the human device, preserving more high-frequency content in the canine ECG signal. These findings underscore that ECG reference intervals and diagnostic thresholds are device-specific and cannot be used interchangeably across different electrocardiograph systems. Veterinary clinicians should use reference intervals validated for their specific device and be cautious when comparing ECG findings across institutions using different equipment or computer-based analysis programs.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.