Atrioventricular junctional ablation: The good, the bad, the better

Abstract

Background: The management of patients with atrial fibrillation and an abnormally fast ventricular response has been through the use of pharmacologic agents. In those cases where rate control cannot be achieved pharmacologically, a standard approach has been atrioventricular (AV) junctional ablation and ventricular pacemaker implantation to achieve a stable ventricular rate. Long-term ventricular pacing has been shown to result in diminished ventricular function that can lead to heart failure.

Objective: To describe an experimental and clinical study demonstrating a modified form of AV junction ablation.

Methods: Ablation of the slow and fast AV nodal input does not produce AV block. Ablation of the connection between the two induces AV block, leaving the AV node and His bundle intact.

Results: Subsequently the escape heart rate is close to normal and responds well to exercise.

Conclusion: In a clinical study with a 42 month follow-up, the modified procedure resulted in significantly reduced pacemaker dependence and mortality compared to the standard AV ablation procedure.

Keywords: AV node; Atrial fibrillation; Atrioventricular junction; Catheter ablation; Fast pathway; His bundle pacing; Slow pathway.

Figure 1

Diagrammatic view of the atrial septum in the right atrium to identify the various atrial nodal inputs to the atrioventricular (AV) node and His bundle. The fast pathway (yellow) runs along the anterior limbus of the oval fossa to enter the AV node (blue triangle), at the apex of which is the His bundle (red dot). The slow pathway runs from the coronary sinus (green area) to the AV node, whereas the central transitional cells traverse the area between the slow and fast pathways to input to the AV node. (Reproduced from Figure 1 in Patel D, Daoud EG. Atrioventricular junction ablation for atrial fibrillation. Heart Failure Clinics 2016;12:245–255, which was adapted from Anderson RH, Cook AC. The structure and components of the atrial chambers. Europace 2007;9(Suppl6):vi3; with permission.)