A Membranous Septal Aneurysm Causing Right Ventricular Outflow Tract Obstruction in an Adult

We describe a case of a 69-year-old female referred for the evaluation of exertional dyspnea, with a small membranous ventricular septal defect (VSD) and right ventricle (RV) outflow tract obstruction. Using transthoracic echo was diagnosed VSD with left to right shunting and transesophageal echo (TEE) was used to a better anatomical characterization. TEE showed a perimembranous subaortic VSD that developed a high-velocity flow in RV. Pulmonary valve appears normal and right ventricular infundibular hypertrophy or double-chambered RV was excluded from the study. Furthermore, TEE showed a malaligned VSD and the presence of perimembranous mobile tissue protruding in RV. We hypothesized that this tissue can be attributed to broken septum aneurysm and protruding during systole, it causes a dynamic RV output tract obstruction.