Many complications associated with the transcatheter procedure to implant the Amplatzer septal occluder (ASO) device have emerged in the past 5 years. We discuss 2 examples here. In case 1, the ASO device was 3 mm larger than the balloon-stretched diameter. In case 2, the ASO device was the same size as the balloon-stretched diameter. One week after their discharge from the hospital, a complete atrioventricular block was detected in case 1, and complex arrhythmias consisting of atrial flutter and variable degrees of atrioventricular nodal conductions were recorded in case 2. We report our treatment of these patients and their full recovery to normal sinus rhythm at 3-week (case 1) and 6-week (case 2) follow-up examinations.