Ablation of anterorseptal accessory pathway using both antegrade and retrograde approaches

Background: 52 year old male with symptomatic narrow complex tachycardia terminated with adenosine. ECG is consistent with pre-excitation from anteroseptal (AS) accessory pathway (AP). Objective: To describe frst reported case of ablating AS AP using the combined antegrade and retrograde approaches Methods: N/A Results: Electrophysiological maneuvers were performed including parahisian pacing and apical/basal pacing which confrmed AS AP was present with weak antegrade conduction and solid retrograde conduction and the AP effective refractory period at 600 ms was 300 ms. Due to presence of very small His at the earliest site using the antegrade approach in the RV/His area (Figure A) no ablation was done and retrograde approach Aorta/non coronary CUSP showed early site with no His (Figure B) and ablation at that site resulted in immediate elimination of the antegrade conduction which was no longer present after that. However, retrograde conduction was still present with no change and confrmed by repeating the prior maneuvers as well as by using adenosine which showed several echo beats with no pre-excitation (Figure C). We performed further ablation using antegrade approach on the opposite successful ablation site which was minimally distal to the prior site (Figure D). No further retrograde conduction was present after that. All intervals were normal. Conclusion: Successful ablation of AS AP might require combining the antegrade and retrograde approaches. [Figure Presented]