Background Doubly committed or subarterial ventricular septal defect (sVSD),located between the cristaesupraventricularis and pulmonary valve,is common in the Eastern countries accounting for approximately 20％-30％ of all VSD cases.Transcatheter device closure has been widely performed in patients with perimembranous VSD (pmVSD).However,due to its special anatomy and potential effect on aortic valve function,sVSD is still considered a technical challenge for interventional therapy.Moreover,there is no large scale clinical report of transcatheter closure for sVSD and long-term follow-up result until now.Thus,this study was to describe our experience with transcatheter closure for sVSD using modified double-disk occluder (MDDO) and compared the clinical efficacy and safety of device closure for sVSD and pmVSD.