Preferential para-hisian atrial tachycardia ablation from aortic root: a single centre experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Para-hisian atrial tachycardia (PH-AT) radiofrequency ablation carries a significant risk of atrio-ventricular block due to proximity to the conduction system. Ablation from noncoronary cusp (NCC) has been proposed as an alternative approach; however, the best strategy remains unknown (1). Purpose Evaluation of a strategy based on PH-AT ablation preferably from aortic root. Methods Observational study of all consecutive atrial tachycardia cases submitted to our institution for electrophysiological study and ablation from 2014 to 2020. If the earliest atrial electrogram was near the His bundle, aortic root mapping and ablation from this position was pursued. Results A total of 105 procedures of atrial tachycardia ablation were performed in 98 patients. 25 cases (24%) were PH-AT. Mean follow-up was 19.2 months (5.8 – 36.8). Table 1 summarizes basal characteristics of our population and ablation details. In the PH-AT group, successful ablation was achieved from aortic root in 21 cases, right atrium (RA) in 1 case and from both sites in 2 cases. The patient whose ablation was performed exclusively from RA was because of pacemaker dependency. In one of the patients with dual approach, RA was firstly attempted because of aortic prosthetic valve but tachycardia recurred, so aortic root was targeted; in the other case, radiofrequency was applied from RA due to electrophysiologist preference, but after second degree transient AV block, procedure was completed from NCC. Acute success rate was similar in both groups (para-hisian and non-para-hisian, 100% and 96%, P=0.33). Figure 1 shows a trend towards less atrial arrhythmias recurrence in PH-AT compared to other atrial tachycardia origins. In the PH-AT group, only two procedure complications were found: a case of femoral artery pseudoaneurysm (ablation from aortic root) and the previous reported transient second-degree AV block (during ablation from RA). No systemic embolism was observed. Conclusions Radiofrequency ablation of PH-AT from aortic root seems to be practicable, effective, and safe.