Comparison of three methods of measuring vertebral heart size in German Shepherd dogs

The method of measuring the heart size in thoracic radiography by comparing it to the length of thoracic vertebrae is marked as vertebral heart size (VHS). Besides the original VHS measurement suggested by Buchanan and Bücheler, there are modifications of these measurements in literature. With the aim to evaluate differences between different methods of VHS measurement, we compared radiographs of six clinically healthy dogs of the same breed and age (German shepherd dogs, 3 years of age), whose heart size was measured according to three different methods of VHS measurement. There were not significant differences between the values obtained by different methods of VHS measurement. In our study, we also compared findings of radiographs subjective assessment and VHS measurements. The second and third method of measurement were much more consistent to subjective assessment than the first method. Diagnosis of cardiac abnormalities in dogs should not be based solely on the measurement of vertebral heart size. However, VHS measurement is very suitable for clinical practice. According to the study reported here, the second method of VHS measurement described in this paper, was recommended