Association between vertebral heart score measurement and overweight condition in dogs

Introduction
Vertebral heart score (VHS) is used to assess heart size on thoracic radiographs. Association between VHS and overweight condition in dogs of different breeds is still unknown. The aim of this study is to determine if VHS is influenced by overweight condition in dogs. The hypothesis is that VHS is influenced by BCS and T4 ratio.

Methods
Recruitment criteria for this retrospective study were the presence of a minimum of 2 thoracic radiographic views and a diagnosis of “normal echocardiographic examination” in medical records from 2013 to 2016. Body weight, BCS and breed were extracted. VHS and overweight condition were calculated. Dogs from breeds with a normal maximal VHS < 11 (group 1) and from breeds with a normal maximal VHS > 11 (group 2) were separated. Statistical analyses were performed using XLStat® software.

Results
Fifty-one dogs were included in the study. Body weight ranged from 3.7 to 44.8 kg and was not recorded in 2 dogs. These dogs were not excluded because of the BCS was recorded for these dogs. BCS ranged from 3 to 9. Thirteen dogs had a VHS value superior to the normal range and all of them had BCS ≥ 4. A weak positive correlation was found between BCS and T4 ratio (P ≤ 0.001, R2=0.4). There was a positive relationship between BCS and VHS (ANCOVA, P ≤ 0.003) for each group and between T4 ratio and VHS for each group (ANCOVA, P ≤ 0.001).

Discussion/Conclusions
This study confirms that the T4 ratio is correlated to BCS evaluated clinically. This ratio could be used to assess overweight condition on thoracic radiographs. VHS is influenced by BCS and the T4 ratio; therefore, VHS should be use with caution in overweighed dogs.