Objective    To evaluate the clinical effect and safety of transcatheter closure on adult large atrial septal defect (ASD) through the follow-up observation.     Methods    Eighty-seven patients having received the transcatheter closure for ASD (diameter >30 mm) in the our department

and been followed up for more than 1 year were enrolled as the subjects. The patients were examined by electrocardiography (ECG) and transthoracic echocardiography (TTE) before and 3 d

1 month

6 months and 1 year after the operation. The patients were also monitored by ECG and TTE during the operation

.     Results    The patients had an average ASD diameter of  30-38 (33.8±1.85) mm before the transcatheter closure. The occluders that were implanted in the patients during the operation had an average diameter of 36-42 (39.2±1.38) mm. First- and second-degree atrioventricular block occurred in 2 cases

and transient sinus bradycardia occurred in 1 case during the operation. In the follow-up period

the inner diameters of right atrium and right ventricle decreased significantly and fell within the normal range in all cases (

P

<

0.05); the end-diastolic inner diameters of left ventricle increased gradually

and yet were still within the normal range. One year after the transcatheter closure

only 2 cases had complete right bundle branch block without severe complicating diseases.     Conclusion    Transcatheter closure is an effective and safe means of curing large ASD.