A new method of computing the vertebral heart scale by means of direct standardisation.

Objectives: The aim of this study was to describe and compare a simplified vertebral heart scale computation method (Objective VHS) with the original Buchanan method (Buchanan VHS).

Methods: The Objective VHS was compared to the Buchanan VHS method in 42 dogs including 14 healthy dogs and 28 dogs with mitral insufficiency. For the Objective VHS, the sum of the length of the long and short axes of the cardiac silhouette obtained in centimetres using a metric ruler was subsequently converted into units of vertebral length by means of a direct standardization method. The Buchanan VHS was obtained as previously described.

Results: No significant differences in vertebral heart scale values were found between the two methods in all dogs. There was a strong positive correlation (0·99) between Objective VHS and Buchanan VHS.

Clinical Significance: The use of a direct standardization method based on a unit conversion allows -computation of vertebral heart scale values without transposing long and short axes to the cranial edge of T4.