Abstract
Background:
Different animal species have been used in cardiological and interventional experiments. Detailed knowledge of coronary dominance in dogs can improve veterinary practice in these species. The right coronary artery is dominant in humans and pigs, while the left coronary artery is dominant in dogs and cattle.

Aim:
To provide a qualitative and biometric description of coronary dominance in dogs.

Methods:
The local ethics committee approved this study, and all samples were collected from veterinary clinics in Bucaramanga, Colombia. The coronary vasculature of the hearts of from 30 dogs was perfused with semi-synthetic resin (80% Palatal GP40L and 20% styrene), and morphometric measurements were recorded.

Results:
A pattern of left coronary dominance was identified in the observed sample, with subtype II being the most prevalent in 25 (83.3%) hearts and subtype III in only 5 (16.7%) cases. The right coronary artery terminated between the right margin and the cardiac cross in 25 (83.3%) patients. The left coronary artery had a higher proximal caliber (2.98 ± 0.71mm) than the right coronary artery (1.99 ± 0.77mm) (p = 0.001). The paraconal interventricular branch terminated in the posterior aspect of the left ventricle in 20 (66.7%) cases, and its proximal caliber was 2.29 ± 0.55 mm. The circumflex branch terminated in the subsinusal interventricular groove or cardiac cross in 23 (93.3%) patients, which is the main characteristic of left dominance.

Conclusion:
Our study enhances and classifies left coronary dominance in dogs by subtypes described in previous studies. This anatomical and biometric evaluation of coronary vessels optimizes the diagnosis, planning of cardiovascular procedures, and development of personalized clinical interventions in veterinary medicine.

Key words: Dogs, Coronary dominance, Left coronary artery, Circumflex branch, Subsinusal branch