Reversible atrioventricular block associated with closure of atrial septal defects using the amplatzer device Original Research Article

Objectives We sought to determine the incidence, nature, and predisposing factors of atrioventricular block (AVB) associated with closure of atrial septal defects (ASDs) using the Amplatzer septal occluder (ASO). Background In our institution, 162 patients underwent ASD closure using ASO between December 1997 and December 2001. This includes small children with large defects. Methods Electrocardiographic tracings during ASO implantation and at follow-up visits were reviewed. Anatomic characteristics and device size were assessed as potential risk factors for AVB. Results Ten patients (6.2%) presented with new-onset (n = 9) or aggravation of preexisting (n = 1) AVB. Atrioventricular block occurred during the procedure (n = 3) or was first noted one day to one week later (n = 7). Patients had first-degree (n = 4), second-degree Wenckebach (n = 4), or third-degree (n = 2) AVB, with no symptoms or hemodynamic compromise. First-degree AVB persisted in two patients at 12 and 33 months of follow-up, whereas most recovered normal AV conduction within one (n = 7) or six months (n = 1). A larger shunt (Qp/Qs ratio 2.8 ± 0.9 vs. 2.1 ± 0.8, p < 0.01) and device size (24 ± 5 vs. 19 ± 6 mm, p < 0.01) were the only determinant factors for AVB. A device size ≥19 mm was used in 90% (9 of 10) of patients who developed AVB, as compared with 49% of those without AVB (p < 0.02). Conclusions Closure of ASDs using the large ASO can be associated with the development of AV block and mandate a closer follow-up. In our series, however, all AVBs resolved or improved spontaneously, with no recurrence at mid-term follow-up.