Rare atrioventricular septal defects in veterinary species: Complete atrioventricular septal defect in a dog and double‐outlet right atrium in a cat

Abstract

AbstractCase 1: A 9‐year‐old Yorkshire terrier mix was referred for evaluation of heart failure presumed to be secondary to myxomatous mitral valve disease. Case 2: A 6‐year‐old Domestic Longhair cat was referred for evaluation of heart failure presumed to be secondary to hypertrophic cardiomyopathy. Thoracic radiographs revealed pulmonary overcirculation suggestive of a cardiac shunt in both cases. Echocardiographic findings confirmed the diagnosis of rare atrioventricular septal defects (AVSDs): complete AVSD (case 1) and double‐outlet right atrium (case 2). Complete AVSDs are rare congenital cardiac defects in veterinary species that result from inappropriate embryogenesis of the atrioventricular septum. Sequelae include congestive heart failure and possibly shunt reversal due to concomitant pulmonary hypertension. Few veterinary reports describe the natural timeline of this condition and outcomes. This report describes both a dog and cat that presented symptomatic in adulthood, were diagnosed via echocardiography and medically managed long‐term.