Abstract 4143915: A Case of Double Chambered Right Ventricle Associated with Ventricular Septal Defect- an Overlooked Congenital Heart Disease

Case description: A 68-year-old man with history of prostate cancer, anal and scrotal squamous cell carcinoma presented to the cardiology clinic with dyspnea on exertion with exercise tolerance limited to 2 flights of stairs. Physical examination showed grade 3/6 holosystolic murmur best heard at the left lower sternal edge. A transthoracic echocardiograph (TTE) revealed an ejection fraction of 65%, prominent muscle bound right ventricular outflow tract obstruction (RVOT) consistent with double chambered right ventricle (DCRV), and a Windsock deformity of the membranous interventricular septum through which there was a VSD with left to right shunting. The maximal pressure gradient across the VSD was approximately 116mmHg. The pulmonary artery systolic pressure was 61mmHg; consistent with severe pulmonary artery hypertension. Discussion: DCRV is a rare condition accounting for 0.5 to 2% of congenital heart diseases. It is characterized by abnormal muscle bands that divide the right ventricle into two chambers; a proximal high-pressure and distal low-pressure chamber, leading to progressive right ventricular outflow tract obstruction (RVOT). This condition rarely occurs in isolation and is often ventricular septal defect (VSD), which is seen in up to 90% of DCRV cases. DCRV may go undiagnosed until adulthood. As the degree of RVOT increases, patients present with shortness of breath and decreased exercise tolerance. TTE is an invaluable tool for diagnosing and determining the severity of obstruction through pulsed and continuous wave doppler to measure the gradient across the hypertrophied muscle bundles. Current guidelines recommend surgery in asymptomatic patients with severe right ventricular obstruction with a pressure gradient greater than 40 mmHg between the proximal and distal compartments within the right ventricle. Even though our patient was mildly symptomatic, his significant pressure gradient of 116 mmHg warrants surgical evaluation. Conclusion: DCRV is a rare and often overlooked congenital heart disease. The patient, despite mild symptoms, exhibited classic features of DCRV and associated VSD, highlighting the potential for this condition to persist undiagnosed into late adulthood. The presence of severe pulmonary hypertension further emphasizes the importance of early detection and ongoing management to prevent severe complications such as heart failure and sudden cardiac death.