Lack of correlation between canine heart rate and body size in veterinary clinical practice

Methods: The investigation was performed via two different studies: a retrospective analysis performed on 243 electrocardiogram recordings and a prospective study based on 153 standardised clinical examinations. Results: The two separate studies did not show any significant correlation between HR and bodyweight (P=0 center dot 5705 and P=0 center dot 4682, respectively). Subject's breed morphology and gender did not appear to affect HR measured under these circumstances. However, dogs under the age of one year seem to have significantly higher HRs than older dogs (P < 0 center dot 05). Finally, subject's demeanour was also found to have a significant influence on HR; lower values were recorded in relaxed dogs, and higher rates were documented in excited, nervous dogs (P < 0 center dot 05). Clinical Significance: Normal HR could be erroneously interpreted as bradycardia or tachycardia if bodyweight was to be considered a determinant factor. Instead, HR in healthy dogs undergoing routine clinical examination is related to their demeanour or age, if younger than 12 months, but does not appear to be related to bodyweight.