COMPARATIVE ANATOMY OF BLOOD-SUPPLY OF CARDIAC VENTRICLES IN ALBINO-RAT AND GUINEA-PIG

The hearts of 118 albino rats and 80 guinea-pigs were investigated by angiography. The average pattern of distribution of the coronary blood supply to the rat''s heart is found to be nearly a balanced circulation, i.e., the right coronary artery mainly supplies the right ventricle and the major part of the interventricular septum in 50.9% of the hearts. The left coronary artery supplies the left ventricle and the whole of the interventricular septum in 49% of the cases. The distribution of the coronary arteries in the heart of the guinea-pig is similar to that of the rat with some variations in the length and extent of distribution of each coronary artery. The right coronary artery is frequently smaller than its left counterpart; its area of distribution is less. The right coronary supplies the anterior and a smaller part (or none) of the posterior right ventricle. The major part of the interventricular septum is most frequently (81.2%) supplied by the septal branch of the right coronary artery. In both species of animals, small branches from the anterior interventricular artery supply the anterior part of the septum, while the same from the posterior interventricular artery supply its posterior part.