Effect of body position on electrocardiographic recordings in dogs

Objective To determine whether body position (standing vs right lateral recumbency) altered the quality of the electrocardiogram ( ECG ) and value of ECG variables in dogs when the ECG was recorded using American Heart Association guidelines for frequency response. Design Crossover study using a convenience sample. Methods ECGs were recorded twice in 65 sled dogs in random order with each dog standing or placed in right lateral recumbency. Lead II and three semi‐orthogonal leads ( I , aVF , and V 10 ) were recorded and muscle tremor artefact was assessed. Results Lead II ECGs obtained from dogs in right lateral recumbency had less muscle tremor artefact and consequently a shorter QRS duration than ECGs obtained with the dogs standing. The P , Q , R and S wave amplitudes differed in selected leads and the mean electrical axis was shifted 20° to the right when dogs were in right lateral recumbency. Conclusions Right lateral recumbency improves the quality of ECG recording in dogs by decreasing muscle tremor artefact, alters the amplitude of P , R and S waves in specific leads and results in a rightward shift in the mean electrical axis, relative to standing.