Unique Shield: An Obstructive Huge Tricuspid Pouch Associated With Ventricular Septal Defect Developing Into Adulthood

BACKGROUND: Tricuspid valve (TV) pouch is a rare entity associated with ventricular septal defect (VSD). It is even rarer to cause right ventricular (RV) inflow obstruction. CASE SUMMARY: A 43-year woman presented with exertional palpitations for 2 years, diagnosed with a large TV pouch causing significant RV inflow obstruction without pulmonary arterial hypertension (PAH). Cardiac magnetic resonance revealed a large perimembranous VSD with bidirectional flow into the TV pouch, which had no effective communication with the right ventricle, preventing a significant left-to-right shunt and PAH. Surgical correction involved partial excision of the pouch and closure of the VSD, preserving the TV integrity. DISCUSSION: This case highlights a rare hemodynamic presentation of the TV pouch and its potential to cause RV inflow obstruction and prevent PAH in a large VSD. TAKE-HOME MESSAGE: Follow-up (at least every 3-4 years) for these cases where VSDs are spontaneously closed by TV or aneurysmal membranous septum would be beneficial.