# Surgical Correction of Infundibular Muscular Ventricular Septal Defect in a Cat: A Case Report

## TL;DR

A cat with a rare heart defect underwent successful surgery using a method rarely used in feline cardiac procedures, leading to a full recovery.

## Contribution

This is the first reported surgical correction of an infundibular muscular VSD in a cat using cardiopulmonary bypass.

## Key findings

- The cat recovered well with only a minor residual defect 490 days post-surgery.
- The surgical technique using cardiopulmonary bypass was viable for feline congenital heart disease.
- A temporary complication occurred but was resolved with non-surgical treatment.

## Abstract

In a groundbreaking procedure, our team successfully performed surgery on a young Ragdoll cat with a rare type of heart defect known as an infundibular muscular ventricular septal defect, which is a hole between the two lower heart chambers. This condition, if left untreated, can lead to severe heart problems. Therefore, the surgery was performed using a method called cardiopulmonary bypass, which is quite unusual in cats. This approach involved stopping the heart temporarily to repair the defect safely. Despite being a challenging situation, in which an adjacent structure was unintentionally damaged intraoperatively, resulting in a temporary complication that was treated non-surgically, the cat recovered well. By 490 days postoperatively, the cat was healthy with only a minor residual defect, showing that the heart had nearly returned to its normal size. This case highlights a promising surgical option for treating similar heart defects in cats, which can potentially improve their quality of life significantly. Therefore, with proper surgical treatment, even in cases of severe congenital heart disease in cats, owners will be able to live with their cats without the need for numerous medications.

Ventricular septal defects (VSDs) can lead to congestive heart failure and pulmonary hypertension, particularly in patients with large shunts. However, no surgical treatment for feline VSD has been reported. Here, we elucidated the first surgical correction of an infundibular muscular VSD in a one-year-old Ragdoll cat, atypically located and classified under the Soto classification rather than the standard Kirklin classification, through cardiac arrest using cardiopulmonary bypass—a method rarely used in feline cardiac surgery. Detailed echocardiography revealed that the defect required intervention owing to left heart and main pulmonary artery enlargement. Despite the VSD being located on the contralateral side, as anticipated in the preoperative examinations, the choice of median sternotomy allowed for the successful closure of the defect. Conversely, the insertion of two cannulas into the ascending aorta resulted in damage to the adjacent thoracic duct, causing transient chylothorax, which was resolved with conservative treatment. Cardiac arrest induced by a cardioplegic solution facilitated the surgical procedure, although it leads to anemia in cats. However, on postoperative day 490, the patient exhibited only minor residual shunting, with normalized heart size, and remained healthy. This technique appears to be a viable treatment option for congenital heart disease in cats.