The circumflex branch was located on the coronary groove, originating two to five atrial branches (3.00 [+ or -] 1.55), and from three to seven ventricular branches (4.50 [+ or -] 1.97).
When atrial branches were considered, the left coronary artery yielded 3.00 [+ or -] 1.55 branches and the right one, 3.50 [+ or -] 1.38 branches, with no significant difference between them (p = 0.56).
There was a positive linear correlation between the number of atrial branches from the circumflex branch and the ventricular branches originating in the paraconal interventricular branch (r = 0.85).
The number of atrial branches originating from the circumflex branch was described ranging from one to six (average of 4.1 branches) in the domestic dog (Oliveira et al.), whereas in P.
While Evans & De Lahunta (2013) described only one or two atrial branches of the right coronary artery in domestic dogs; Oliveira et al.
With the advent of new percutaneous and surgical techniques used in the treatment of coronary artery disease, and supraventricular bradi-tachy-arrhythmias including atrial fibrillation, awareness of origin and routes of the atrial branches, particularly the sinoatrial nodal branches of coronary tree, have assumed great importance (10-12).
The surgical significance of the atrial branches of the coronary arteries.
Atrial branches: One to three atrial branches arose from the right side of the RCA and extended upwards and to the right on the anterior surface of the right atrium.
Atrial branches: Usually, there were two to three atrial branches which extended upwards from the second segment to the posterior surface of the right atrium.
Atrial arteries: There were one to two atrial branches which arose from its upper border.
One to two atrial branches arose from its upper border and passed upwards on the posterior surface of the left atrium.