Abstract
A 50-year-old man presented with an episode of chest pain. Cardiac magnetic resonance revealed the presence of a large ventricular septal aneurysm partially closing a perimembranous ventricular septal defect, prolapsing into the right ventricular outflow tract, and mimicking a mass. We illustrate the diagnostic approach and management of such ventricular septal aneurysms. (Level of Difficulty: Advanced.).