Introduction: Novel transcatheter techniques to control interatrial communications exist. Devices with restrictive fenestrations can be implanted to maintain patency of an atrial septostomy, or reduce an interatrial communication. Experience with these devices in children is limited. Patients and Methods: Fenestrated atrial septal devices were implanted into 10 children (5 male, age 1.5-15.5 years). Devices were modified by the manufacturer (MM, n = 6), or by a modification of an atrial septal occlusion device by the operator (OM, n = 4). Seven devices were implanted after atrial septal puncture and septostomy for severe symptomatic pulmonary hypertension (PHT) [4 heart failure, 3 syncopel, according to World Health Organisation Guidelines. Two devices were implanted to reduce left to right shunting through large atrial septal defects with associated PHT. One device was implanted acutely to offload the left atrium during extracorporal circulatory support prior to heart transplantation. Warfarin (n = 5), aspirin (n = 4), or heparin (n = 1) were used for prevention of fenestration thrombosis. Results: Symptoms in all patients with PHT improved after implantation; syncope recurred with fenestration occlusion in one patient. Nine patients were followed up to a mean of 26 months. Five devices (all MM; warfarin n = 4, aspirin n = 1) remained patent on echocardiography. Fenestrations occluded in 4 children after median follow-up of 10 months (MM n = 1, OM n = 3, warfarin n = 1, aspirin n = 3). Conclusions: Implantation of fenestrated atria[ devices is feasible and effective; but the occlusion rate is high. Further research on fenestrated atrial septal devices with better long-term Patency, and effective antithrombotic drug treatment is necessary. (C) 2007 Wiley-Liss, Inc.