Progression to late complete atrioventricular block following amplatzer device closure of atrial septal defect in a child.

Atrial septal defect (ASD) closure by interventional catheterization techniques has been widely accepted and is considered a standard treatment for this congenital heart defect. We report the case of a 6-year-old girl who presented with progression of first-degree atrio-ventricular (AV) block to symptomatic, complete heart block after ASD closure with an Amplatzer septal occluder (ASO). Although she received steroids immediately after the procedure when second-degree AV block was seen, her AV conduction slowly deteriorated over 4 years, requiring permanent pacemaker implantation. We can only speculate that the injury to the conduction system was the result of persistent trauma, ischemia, or progressive scarring caused by the ASO on the AV nodal region. It is uncertain if early device removal would have prevented this complication. This case highlights the importance of cardiac rhythm monitoring following ASO implantation for ASD closure on long-term follow-up.

Transthoracic percutaneous access for electroanatomic mapping and catheter ablation of atrial tachycardia in patients with a lateral tunnel Fontan.

BACKGROUND: The incidence of atrial tachycardia following Fontan surgery is high, but access to the pulmonary venous atrium, a frequent site of arrhythmia origin, is limited. OBJECTIVES: The purpose of this study is to report our results with a novel transthoracic percutaneous technique that provides direct access to the pulmonary venous atrium for electrophysiologic procedures. METHODS: Six transthoracic ablation procedures were performed in five patients (age 1.2-17 years, weight 9.2-68.4 kg) with a lateral tunnel Fontan. Under biplane fluoroscopy, a percutaneous needle was advanced at the selected intercostal space toward the pulmonary venous atrium. Once access was confirmed, a sheath was placed over a wire and a Navistar CARTO catheter advanced for mapping and ablation. Additional catheters were placed in the baffle and esophagus for pacing and reference. Atrial tachycardia was induced, electroanatomic mapping performed, and candidate areas tested with entrainment techniques. Radiofrequency ablation was performed and success defined as the inability to reinduce tachycardia using the initiating protocol. RESULTS: All tachycardias were ablated. Procedure time ranged from 3.7 to 4.9 hours, and fluoroscopy time ranged from 31 to 70 minutes. Hospital stay was 2 days. One patient had a pneumothorax and two had a hemothorax that was drained. Tachycardia recurred in one patient at 3 months. Ablation was repeated successfully. Four patients are free of tachycardia at follow-up ranging from 6 to 29 months. Follow-up is not available for one child. CONCLUSION: Transthoracic percutaneous access provided a direct route to the pulmonary venous atrium for successful mapping and radiofrequency ablation in Fontan patients.

Late recovery of surgically-induced atrioventricular block in patients with congenital heart disease.

OBJECTIVES: To assess the incidence and establish possible predictors of late recovery of post-surgical heart block, treated with pacemaker implantation, in patients with congenital heart defects. BACKGROUND: The American College of Cardiology/American Heart Association Task Force has recommended pacemaker implantation for advanced second or third degree atrioventricular block which persists for 7 to 14 days after surgery. The incidence of late recovery of post-surgical heart block following pacemaker implantation has not been reported. METHODS: Records of 44 patients with post-surgical heart block who underwent pacemaker implantation at our institutions since 1976 were reviewed for demographic, anatomic, surgical and surface electrocardiographic data to assess the incidence of, and factors associated with, recovery of atrioventricular conduction on long-term follow-up. RESULTS: 32% (14) of patients recovered atrioventricular conduction at a median follow-up of 5.5 years while 68% (30) remained pacemaker dependent. The groups were similar in age and weight at surgery and period of follow-up p = 0.5). Types of defect and surgical repair were not significantly different (p > 0.1). There was a similar number of patients with second degree-type II block in both groups (p = 0.15). The groups did not differ in timing of pacemaker implantation (<10 days p = 0.14, >14 days p = 0.18). CONCLUSIONS: Late recovery of atrioventricular conduction following pacemaker implantation for postsurgical heart block is common. However, clinical predictors, with reference to current recommendations, could not be identified. Prospective electrophysiologic evaluations may be warranted to establish guidelines for long term pacemaker dependency and criteria for pacing.