I know this is greybeard stuff, but back in the days when all we had was the ECG, the CXR and the angiogram, it was the angio that was the final arbiter of diagnosis, and we had to be reasonably good at getting the catheter into every nook and cranny. These skills persist in the paediatric interventionalist, but even so it is interesting to see techniques come and go. My favourite was to marry a super soft NIH catheter that was made for the Muller steering system and use it with the simpler tip-deflecting guide wire made (still is I think) by Cook. You can use this wire with a Berman catheter too.
In this case, I was investigating a child with pulmonary hypertension of unknown origin. It was proving difficult to pass from the RV into the main pulmonary artery, so I was using the deflector to get a little more direction in the RVOT. As I was turning the tip of the catheter along the septal surface just below the pulmonary valve, it suddenly jumped to the left. As the angiogram shows, it had passed through the small central orifice of a flexible membrane (arrows) which had all but occulded a large perimembraneous VSD.
A majority of VSDs in this position will heal naturally, and this form of membraneous closure is the usual mechanism. Some would call it an aneurysm, but I do not think that is a good use of the word (any more than "atrial septal aneuysm"). An aneurysm is a thinned and bulging wall that once was normal, hardly the case here. It is sad to note that this effort at self repair did not protect the child from the Eisenmenger response.