Finding the right spot and preserve high escape rhythm

• when AV node ablation makes sense
• how to find a good spot for ablation
• what is the best procedural setting

AVN ablation combined with permanent pacing is an established therapy for rate control in patients with symptomatic and treatment refractory AF. This is a relatively simple procedure if you pay attention to little details**:**

• It is advisable to firstly guide the ablation catheter anatomically aiming for the Triangle of Koch. It’s much easier that it sounds. Simply start with introducing catheter into RV, then pull it back slowly and try to keep it medial (septal) by clockwise rotation and basal by bending it at the curve. In this region you should start looking for a good signal.
• An optimal spot for ablation of the compact AVN is with a 1:2 ratio of atrial to ventricular signal size but in patients with AF it can be difficult to use the size of the atrial signals to target the correct anatomical location given the variance in their amplitude. If the His signal is particularly prominent it is likely the catheter is in the proximity of the insulated His bundle (more difficult to ablate) and further withdrawal is required in order to address the more vulnerable compact AVN tissue.
• Depending on catheter a RF ablation is performed at 30–50 W. Usually, impulse duration of around 60 s is sufficient to sustain AV block. For confirmation look for an accelerated junctional rhythm followed by AV block and ventricular stimulation from the pacemaker.