A case of double-chambered right ventricle due to cap-like fibrous tissue and aberrant chordal insertion of tricuspid valve in adult

Background: A double-chambered right ventricle is a rare congenital heart disease where an anomalous structure divides the right ventricle into two cavities. Case: A 78-year-old man with dyspnea was referred to our institution for a double-chambered right ventricle (DCRV) and ventricular septal defect (VSD). Echocardiography showed normal left ventricular function, right ventricular hypertrophy, and mild tricuspid regurgitation. On parasternal short-axis views, color-flow Doppler studies showed a mosaic pattern through the stenotic right ventricular outflow tract (RVOT). Cardiac catheterization showed a 122 mmHg pressure gradient between the high-pressure chamber and the low-pressure chamber of the RVOT. Computed tomography showed a cap-like structure consisting of fibrous tissue, with moderate stenosis, which divided the right ventricle into two cavities. The aberrant tendinous chords supporting the anterior leaflet of the tricuspid valve were found inserted into the anterior wall of the RV (Figure 1). Resection of the cap-like fibrous tissue and abnormal muscle (Figure 2), detachment of aberrant tendinous chords of the tricuspid valve, closure of VSD by direct suture, and tricuspid valve plasty (TVP) were performed. TVP was achieved using an artificial chordae replacement with expanded polytetrafluoroethylene (CV-5) suture and a 32-mm Physio Tricuspid annuloplasty ring (Edwards Lifeline). Postoperative echocardiography revealed no RVOT pressure gradient and a normal right ventricular pressure of 21 mmHg. Discussion: In conclusion, we report a rare case of DCRV secondary to a cap-like structure fibrous tissue with anomalous chordal insertion of a tricuspid valve leaflet.