Applied Anatomy of Perimembranous Ventricular Septal Defect for Transcatheter Device Closure.

Perimembranous ventricular septal defect is a common congenital heart disease effectively treated by transcatheter device closure with high success rates and minimal complications. This review categorizes perimembranous ventricular septal defects into 7 morphologic variants based on anatomical extension and correlates these with echocardiographic classifications: type 1 is central perimembranous; type 2 is superior-anterior extension; type 3 is superior-posterior extension; type 4 is inferior-anterior extension; type 5 is inferior-posterior extension; type 6 is confluent extensions with more than one extension direction; and type 7 is complex type with outlet septum involvement. Type 2 defects are often associated with aortic valve prolapse and regurgitation, requiring soft, flexible devices to minimize valve injury. Type 5 defects lie close to the conduction system; deploying devices within an aneurysmal pouch helps prevent heart block and tricuspid regurgitation. Type 6 and 7 defects sometimes necessitate multiple devices for complete closure. Understanding these anatomical variants aids in selecting appropriate devices and optimizing procedural outcomes.