2.1. Patients

During two study years, 155 patients underwent transcatheter closure of an ASD at Severance Cardiovascular Hospital, Korea. All the patients were diagnosed with ASD based on the findings of transthoracic echocardiography prior to the procedure and considered suitable candidates for transcatheter device closure. Among these patients, those with other hemodynamically significant intracardiac lesions, moderate-to-severe pulmonary hypertension, or RV dysfunction were excluded. Conclusively, 74 patients who agreed to participate in this study were enrolled.