Duble-chambered Right Ventricle Cured Completely by Cardiotomy Under the Extracorporeal Circulation with Cardiopulmonary Bypass System in a Dog

Abstract

A 1-year-10-month-old male Labrador Retriever was presented to the teaching hospital at Tokyo University of Agriculture and Technology for dyspnea with chylothorax. Echocardiography revealed an abnormal intracardiac ventricular structure, which extruded the right ventricular outflow tract. Color-flow Doppler echocardiogram revealed turbulent jet flow in the right ventricular outflow tract. In continuous-wave Doppler echocardiography, flow velocity across the right ventricular outflow tract was 5.19 m/s and the calculated pressure gradient was 107.7 mmHg. Furthermore, the tricuspid septal valve showed hyperplasia, and tricuspid regurgitation was confirmed. Cardiac catheterization revealed marked high blood pressure in the right ventricle. Selective right ventricular catheterization revealed a defect of contrast medium in the right ventricle. These findings suggested that there were a double-chambered right ventricle and congenital tricuspid hypoplasia. After the initial examination, the dog showed frequent tipping condition, so the defect was corrected surgically under the extracorporeal circulation with cardiopulmonary bypass system. The right ventricular outflow tract was divided into two chambers by a muscle-like tissue and a membrane-like object. The muscle like tissue and the membrane-like object were transected. After the operation, disappearace of frequent tipping condition was seen and the pressure gradient across the right ventricular outflow tract was drastically decreased. It showed that the cardiotomy under the extracorporeal circulation with cardiopulmonary bypass system was very useful in the treatment of a dog with double-chambered right ventricle.