Angiographic difference in coronary artery of man, dog, pig, and monkey

Comparative morphological studies on the coronary arteries of the left ventricular free wall were carried out on human, dog, pig, and monkey hearts by using postmortem coronary arteriography, soft X-ray photograms, and the clearing method. The results showed that the types of coronary arteries (types I, II, and III) and connecting portion of anastomotic vessels in the pig and monkey hearts closely resembled those in man. Whereas the dog hearts showed the following characteristics: numerous Type III vessels and anastomoses in the epicardial layer, the existence of only the left predominant type of coronary artery, and the supply of blood to the papillary muscles of the left ventricle mostly through a single branch of the coronary artery. Therefore, it is necessary to take into consideration the basic difference in the structure of the coronary arteries of human and dog hearts, when dogs are used experimentally for research of human ischemic heart disease. The fact that only the papillary muscles of the human heart-compared to animal hearts-are supplied blood from two sources may be advantageous to rescue the papillary muscles from ischemic necrosis.