A new device for transcatheter closure of heart defects was constructed and used to close a patent ductus arteriosus (PDA) in seven adult patients and an atrial septal defect (ASD) in six adult patients. The device consisted of two self-opening umbrellas and a piece of Ivalon. A Dacron patch was sewn on the "male" umbrella for the ASD closure. The device required a 9 Fr introducing venous sheath for PDA and a 14 Fr sheath for the ASD. The venoarterial (right femoral vein-PDA or ASD-left femoral artery) long wire track was arranged. The "male" umbrella and the Ivalon were inserted transvenously one after another, advanced over the long wire across the PDA or ASD and extruded into the aorta or left atrium, respectively. The "female" umbrella was advanced transvenously over the long wire into the pulmonary artery (for PDA) or into the right atrium (for ASD). The metal conus on the long wire was used to pull the "male" umbrella while a special stiff pusher was used to bring the "female" umbrella to the "male" umbrella along the long wire. By these means the umbrellas interlocked at the defect level and closed it. The long wire was then removed through the left femoral artery. Protrusion of the interlocked device through the PDA occurred in one patient and through the ASD in two patients. In all three patients the device was kept on the wire until surgery and an early postrelease device embolization was avoided. In all other patients the defects were successfully closed. The follow-up of 3-27 months was uneventful in all patients. These results indicate that the described procedure is effective and safe, and warrants further clinical trial.