Left-to-Left Acquired Cardiac Shunt: Aorto-Left Atrial Fistula Due to Aortic Infective Endocarditis in a Dog

Infective endocarditis is a severe but rarely diagnosed disease, characterized by the presence of bacterial infection at the level of the cardiac valves. Although the incidence of the disease is very low, the consequences are severe and the prognosis is very poor, outlining a high mortality rate among cases. The present report highlights the case of a 7-year-old dog presented with abrupt changes in the respiratory pattern, obtunded and in lateral recumbency. The physical examination of the patient revealed fever and a IV/VI systolic heart murmur, with the point of maximal intensity on the left hemithorax. Echocardiography identified hyperechoic and cavitary changes beneath the aortic valves and a retrograde turbulent jet originating in the left ventricle outflow tract communicating with the left atrium through a rupture in the aortomitral intervalvular wall. Because of very unstable hemodynamic changes, the dog suddenly died despite the initiation of intensive care supportive treatment, and the postmortem evaluation of the heart confirms the suspicion of infective aortic endocarditis with the development of a paravalvular abscess and an aorto-left atrial fistula.