Presumed congenital Gerbode defect in an American Domestic Shorthair cat

A five-month-old, intact female Domestic Shorthair cat presented to the Kansas State Veterinary Health Center for evaluation of a murmur and exercise intolerance. Physical exam revealed a grade V/VI right, parasternal, holosystolic murmur. On echocardiogram, there was an abnormality in the membranous interventricular septum and tricuspid valve, allowing blood to shunt from the left ventricle to the right atrium. This lesion is consistent with an infravalvular Gerbode defect. The Gerbode defect is a rare, left ventricle-to-right atrial shunt that can be congenital or acquired, and in cats, has only been reported once. At the time of submission, the patient is alive and is maintaining a good quality of life.