Early ECG abnormalities associated with transcatheter closure of atrial septal defects using the Amplatzer (R) septal occluder

Conduction abnormalities and arrhythmias may occur in patients following se cundum atrial septal defect (ASD) closure using the Amplatzer(R) septal occ luder (ASO). Therefore, the aim of this study was to prospectively perform ambulatory ECG monitoring to assess the electrocardiographic effects of tra nscatheter closure (TCC) of ASD using the ASO device. From 5/97 to 3/99, 41 patients with secundum ASD, underwent TCC using the A SO device at a median age of 9.2 y. (0.5-87 y.) and median weight of 34 kg (5.6-88 kg.). Ambulatory Holter monitoring was performed pre- and immediate ly post TCC. Holter analysis included heart rate (HR), ECG intervals, supra ventricular ectopy (SVE), ventricular ectopy (VE), and AV block. No change in baseline rhythm was noted in 37 patients (90%). Changes in AV conduction occurred in 3 patients (7%), including intermittent second degre e AV block type II, and complete AV dissociation post closure. SVE was note d in 26 patients (63%) post closure, ranging from 5-2207 supraventricular p remature beats (SVPB), including 9 patients (23%) with non-sustained suprav entricular tachycardia (SVT), 3 of whom had short runs of SVT prior to clos ure. A significant increase in post-closure number of SVPB per hour (p=0.04 7) was noted. No significant difference was noted in PR interval, ventricul ar premature beats per hour, or QRS duration. Conclusions: Based on ambulatory ECG analysis, TCC of ASD with the ASO devi ce is associated with an acute increase in SVE and a small risk of AV condu ction abnormalities, including complete heart block. Long term follow-up st udies will be necessary to determine late arrhythmia prevalence and relativ e frequency compared with standard surgical ASD repair.