Biventricular aneurysm in a dog

Abstract

An aneurysm is defined as a localized dilation of a blood vessel or heart. It may have either a congenital or an acquired origin and occurs in both humans and animals. Cardiac aneurysms are rare, and are characterized by sacculations of the cardiac wall. The present case report describes the macroscopic and microscopic findings of an aneurysm affecting both ventricles of the heart in a dog. A 7-year-old mixed-breed female dog with osteosarcoma on the left pelvic limb was euthanized and submitted to the veterinary pathology laboratory for necropsy. Macroscopically, besides the lesions in the link, the pericardial sac was adhered to the pericardial surface of the heart and there were two sacculations in both ventricles which communicated widely with the respective ventricle. Microscopically, fibrous tissue adhered to the pericardium, atrophy and necrosis of the cardiomyocytes with replacement by adipocytes were observed in addition to hyperplasia of the tunica media of arterioles and thrombosis. A diagnosis of acquired biventricular cardiac aneurysm was made based on the necropsy findings and microscopic lesions in the heart. We emphasize the importance of performing a necropsy and examining tissues histologically for the diagnosis of this rare condition. Ventricular aneurysms should be included in the differential diagnosis of cardiovascular disease in dogs.