OBJECTIVE To assess the efficacy and complications of device occlusion of atrial septal defects in adults, using the Amplatzer septal occluder (ASO).

DESIGN A prospective interventional study.

SETTING Paediatric cardiology departments in two European teaching hospitals.

PATIENTS The first 20 patients accepted for atrial septal defect device occlusion, on the basis of transoesophageal echocardiography. Sixteen patients had larger defects with right heart dilatation, while the primary indication for closure in four was a history of early paradoxical embolism.

INTERVENTIONS Transcatheter atrial septal defect occlusions performed under transoesophageal echocardiography and fluoroscopic guidance between December 1996 and June 1998.

OUTCOME MEASURES Success of deployment of ASO devices, procedure and fluoroscopic times, complications, and symptoms.

RESULTS The ASO device was successfully implanted in all 20 patients (14 female), median age 44.2 years, with no complications. Of the 16 patients with right heart dilatation, the median Qp:Qs was 2.5:1. Defects measured 11–22 mm (median 18) on transoesophageal echocardiography, with balloon sized diameter (and device size) of 13–28 mm (median 20). For all 20 patients, the procedure time ranged from 38–78 minutes (median 61), and fluoroscopy 8.4–24.7 minutes (median 15.2). There were residual shunts in three patients at the end of the procedure, which were trivial (⩽ 1 mm) as assessed by transoesophageal echocardiography, and persisted for more than six months in only one patient. Follow up ranged from 0.1–1.5 years (median 0.7). There have been no late complications.

CONCLUSIONS The ASO device can be used successfully to close selected oval fossa defects in adults, with minimal procedural morbidity and excellent early results.