Data on mid- and long-term follow-up for the recent devices for closure of secundum-type atrial septal defects are limited. The purpose of our retrospective study was to report the effectiveness of transcatheter closure in patients with various morphological types of atrial septal defect other than centrally located defects within the oval fossa using the CardioSEAL and CardioSEAL-Starflex occluder. A total of 91 patients (age 1.5-71 years, median 6 years) underwent transcatheter closure. On the transesophageal echocardiogram, defect size varied from 6 to 18 mm with an estimated stretched diameter of 11 to 24 mm, median 15 mm; the ratio of the stretched diameter to septal length ranged from 0.28 to 0.68. Mean follow-up was 28.7 +/- 11,9 months (range 3-46 months). Isolated secundum-type defects were present in 59 patients (65%), multiple septal defects including patients with perforated atrial septal aneurysms and defects with deficient atrial rim in 32 patients (35%). Occlusion rate using device diameters from 23 to 40 mm increased from 66% (60/91 patients) immediately after implantation to 86% (48/56 patients) 24 months after implantation. Patients with isolated secundum-type defects presented with a significantly higher primary closure rate (45/59 patients, 76%) compared to patients with various defect morphology. Closure rate did not depend on the type of implanted device modification. No thrombus formation, sustained atrial arrhythmia or infective endocarditis occurred. Serial transthoracic echocardiographic findings revealed protrusion of one left-sided arm onto the right atrial aspect in 5 patients; malposition of one right-sided superior arm of the device was observed in 7 patients. Fluoroscopy showed single fatigue fracture in 7 patients (7.7%) within the first 6 months after implantation. These results demonstrate that transcatheter closure with the double umbrella device was effective and safe on medium-term follow-up and could be extended to atrial septal defects of various morphology.