Clinical and imaging features with longitudinal follow-up in a guinea pig (Cavia porcellus) with ventricular septal defect.

Ventricular septal defect (VSD) is a rare and sparsely reported congenital heart disease in guinea pigs that arises from embryonic maldevelopment or misalignment of the interventricular septum, leading to an interventricular communication. A 2.5-year-old intact male guinea pig (Cavia porcellus) that weighed 0.713 kg was presented for a fractured right mandibular incisor, and an incidental grade V/VI right parasternal systolic murmur was detected in the absence of clinical signs of cardiac disease. Radiographic imaging revealed an enlarged cardiac silhouette in the ventrodorsal thoracic radiograph (10.0) with a normal lateral vertebral heart scale of 7.2. Echocardiography identified a small restrictive perimembranous VSD with left-to-right shunting and a peak ventricular pressure gradient of 80 mmHg, without additional morphologic or functional cardiac abnormalities. At the time of publication, this animal had remained stable without medical or surgical intervention and had undergone 12 anesthetic events for occlusal adjustments related to a variety of dental abnormalities resulting in malocclusion without significant complications. Similar to domestic small animal species with restrictive VSDs, guinea pigs can remain subclinical and stable under repeated anesthetic events.