Atrioventricular Junction Ablation for Atrial Fibrillation

Transcatheter ablation of the atrioventricular junction in refractory atrial fibrillation: A clinicopathological study

BACKGROUND

Catheter ablation of the specialized atrioventricular junction (AVJ) with a right-side approach is an effective therapy for refractory atrial fibrillation with fast ventricular rate. Our aim is to assess the efficacy of the procedure in a single center experience and investigate the histologic findings of AVJ after catheter ablation.

METHODS

A) Analysis of AVJ ablation efficacy in a consecutive series of patients with refractory atrial fibrillation; B) Histopathologic study of the conduction system by serial section technique and clinical-electrophysiologic correlation in four patients who underwent AVJ ablation.

RESULTS

A) Right-sided AVJ ablation was successful in all 87 consecutive patients (mean procedural time 19.2±17.9 min). Energy applications ranged from 1 to 27 (mean 5.8±5.1) with eight patients (9%) requiring > 15 applications. B) Fibrotic disruption of atrioventricular (AV) node and/or His bundle interruption was found in three cases with previous AVJ ablation. In the case requiring a left side approach, the compact AV node and common His bundle appeared undamaged whereas extensive fibrosis of the summit of the ventricular septum, branching His bundle and proximal bundle branches was found. Noteworthy, a continuity between the septal and anterior tricuspid valve leaflets was present.

CONCLUSION

Our data confirm that the ideal site for ablation of the specialized AVJ is the AV node. In selected cases with unsuccessful AV node ablation, a shift towards the His bundle is needed. A continuity between the septal and anterior leaflets of the tricuspid valve may protect the His bundle as to require multiple shocks and prolong the procedure.

Acute and long-term outcomes of left-sided atrioventricular node ablation in patients with atrial fibrillation

PURPOSE

To present our experience regarding acute and long-term outcomes of left-sided atrioventricular node (AVN) ablation in patients with atrial fibrillation (AF).

METHODS

A total of 47 patients with AF in whom left-sided AVN ablation via retroaortic approach as a first-line approach were enrolled in this retrospective study. Indications for AVN ablation were high ventricular rate refractory to medical therapy, inappropriate implantable cardioverter defibrillator (ICD) shocks, or loss of cardiac resynchronization therapy (CRT) pacing. Both acute and long-term outcomes were assessed for all participants.

RESULTS

Left-sided AVN ablation was successfully performed in 46/47 (98%) patients without any procedural complication. In the remaining 1 patient (2%), right-sided AVN ablation was performed. No mortality was observed within 30 days of the procedure. Upgrade to CRT was performed in 9 (19%) of the patients. During the median 22.5 months of follow-up, all-cause mortality was 25%. Device interrogations on the last clinical visit revealed complete AV block and intrinsic ventricular rate of < 40 bpm in all patients.

CONCLUSION

Left-sided AVN ablation is a safe and effective procedure without recurrence during long-term follow-up.

Atrioventricular Junction Ablation In Atrial Fibrillation: Choosing The Right Patient And Pacing Device

Atrial fibrillation (AF) is the most common cardiac arrhythmia and despite advancements in rhythm control through direct catheter ablation, maintaining sinus rhythm is not possible in a large proportion of AF patients, who therefore are subject to a rate control strategy only. Nonetheless, in some of these patients pharmacological rate control may be ineffective, often leaving the patient highly symptomatic and at risk of developing tachycardia-induced cardiomyopathy and heart failure (HF). Catheter ablation of the atrioventricular junction (AVJ) with subsequent permanent pacemaker implantation provides definite rate control and represents an attractive therapeutic option when pharmacological rate control is not achieved. In patients with reduced ventricular function, cardiac resynchronization therapy (CRT) should be considered over right ventricular apical (RVA) pacing in order to avoid the deleterious effects associated with a high amount of chronic RVA pacing. Another group of patients that may also benefit from AVJ ablation are HF patients with concomitant AF receiving CRT. In this patient cohort AVJ ablation ensures near 100% biventricular pacing, thus allowing optimization of the therapeutic effects of CRT.