Atrial septum defect in a pygmy goat: a case report

Abstract

Congenital heart defects represent developmental anomalies that cause significant anatomical and functional alterations in the heart’s structure present at birth. Among these defects, atrial septal defect (ASD) is characterized by an abnormal communication between the right and left atria, typically caused by persistence of the foramen ovale or by an incompletely developed interatrial septum. This structural defect results in a moderate volume overload on the right side of the heart, leading to increased pressure and dilation of the right atrium and ventricle. A 3-day-old Pygmy goat neonate weighing 1.5 kg was admitted to the Large Animal Veterinary Hospital of the Federal University of Lavras (UFLA) presenting with marked apathy, absence of the sucking reflex, permanent lateral recumbency, pale mucous membranes, tachycardia with irregular rhythm, and tachypnea, and a soft systolic murmur most evidente over the right cardiac apex, indicating severe systemic and cardiovascular compromise. Supportive treatment was promptly initiated, including parenteral fluid therapy with isotonic Ringer’s lactate solution combined with 50% glucose to address dehydration and hypoglycemia, as well as enteral nutrition administered via a nasogastric tube to ensure adequate caloric intake. Despite intensive medical care and supportive measures, the neonate showed rapid clinical worsening and died seven hours after the onset of treatment. Necropsy examination revealed a globular and enlarged heart, with marked dilation of the right ventricle, presence of a large intracardiac thrombus obstructing the right ventricular outflow tract, and a wide communication between the atria through a persistent foramen ovale (a form of ostium secundum-type ASD). Based on the clinical history, physical examination findings, and necropsy results, a definitive diagnosis of congestive heart failure secondary to ostium secundum atrial septal defect was established. Considering that treatment of congenital cardiac diseases in small ruminants is often economically unfeasible, and given the hereditary nature of this condition, culling of affected animals from the breeding population is generally recommended. The ostium secundum-type ASD in neonate pygmy goats may progress rapidly to congestive heart failure, particularly when complicated by intracardiac thrombosis, and underscores that, despite prompt clinical intervention, necropsy remains essential for definitive diagnosis and for guiding breeding decisions aimed at preventing hereditary cardiac defects.