Effect of Body Position on the 6‐Lead ECG of Dogs

Abstract

ECGs recorded from dogs show characteristic morphology and changes in morphology with various disease states. These changes are determined by comparing individual recordings to reference ranges established from recordings obtained from normal dogs in right lateral (RL) recumbency. Using these reference ranges for ECGs recorded from dogs in other positions may not be valid. We compared ECG complexes from 39 normal dogs obtained in RL, left lateral (LL), and standing (ST) body positions. ECGs from dogs in ST position showed increased Q-wave and R-wave amplitudes in leads I and II, increased R-wave and S-wave amplitudes in leads aVR and aVL, and decreased R-wave and S-wave amplitudes in lead III when compared with recordings obtained in RL position. ECGs from dogs in LL position showed increased R-wave amplitude in leads II, III, and aVF and S-wave amplitude in lead aVL but decreased R-wave amplitude in lead aVR when compared with recordings obtained in RL position. The mean electrical axis (MEA) shifted to the left in ST position but remained within the normal range in LL position. We determined that both a change in the relative position of the recording electrodes with respect to the heart as well as a change in intrathoracic cardiac position contributed to these changes. P-wave amplitude, P-R and S-T intervals, and QRS complex durations remained unaltered by changes in body position. Our findings indicate that ECGs of dogs recorded in RL, LL, and ST positions yield dramatically different results, and investigators should use position-specific reference ranges to minimize potential misinterpretation of ECG results.

Electrocardiographic reference values for healthy Netherland Dwarf rabbits and the influence of body position, age and gender

“…Our findings show that it is important to evaluate MEA in an electrocardiogram with filters disabled because it will show a greater accuracy independently of the methods used to calculate the mean electrical axis, although MEA did not show significant differences between recumbencies, in contrast to results obtained in dogs (Rishniw et al, 2002) and cats (Harvey et al, 2005).…”

“…The other 3 causes might have been produced in our study, especially the shifting of the electrodes, as they were again placed between the two electrocardiograms (sternal and dorsal recumbencies). Regarding body position, previous researchers in dogs (Hanton and Rabemampianina, 2006) or New Zealand rabbits (Saitanov, 1960) did not show differences according to this factor, although other researchers did (Rishniw et al, 2002;Harvey et al, 2005). In our research, body position should be taken into account when the J-T segment duration is assessed.…”

“…Moreover, to the authors' knowledge no studies of electrocardiogram in "trancing" rabbits (dorsal recumbency) have been reported, with the exception of Saitanov (1960), showing that no significant differences were found between supine and prone positions. Recently, Rishniw et al (2002) found that R wave amplitude and MEA were changed depending on position in dogs. These findings were also observed in cats by Harvey et al (2005).…”

Retrospective analysis of co-occurrence of congenital aortic stenosis and pulmonary artery stenosis in dogs

“…Previous studies did not show significant differences in ECG obtained in standing and right lateral position with the exception of the mean electrical axis (Rishniw et al 2002, Pasławska et al 2005. Nine-lead surface electrocardiogram was recorded for each patient to analyse heart rhythm.…”

Comparison of P-wave dispersion in healthy dogs, dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction

“…In many publications the ECG records were compared coming from dogs that were in lateral recumbency or standing position. It has been noticed that the position of the dog does not influence the P-wave duration, P-wave amplitude or PR interval [15,16]. Dogs standing position is used also during toxicological and pharmacological examination.…”