Preferential ablation strategy for parahisian atrial tachycardia from the aortic root: a case series
M Amores Luque, E A Rajjoub, M Tapia Martinez, K Rajjoub, C Lozano Granero, R Matia Frances, A Hernandez Madrid, J L Zamorano Gomez, J Moreno, E FrancoAbstract
Background
Para-Hisian atrial tachycardia (PHAT) poses a therapeutic challenge due to its proximity to the atrioventricular (AV) node and His bundle, increasing the risk of iatrogenic AV block during right atrial ablation. Recent evidence suggests that radiofrequency (RF) ablation via a retroaortic approach from the non-coronary cusp (NCC) of the aortic root may provide an effective and safer alternative to conventional right atrial approaches.
Purpose
This study aimed to evaluate the safety, acute efficacy, and long-term outcomes of PHAT ablation performed preferentially from the NCC, comparing results with focal atrial tachycardias (FAT) originating from other atrial regions.
Methods
We retrospectively analyzed 170 FAT ablation procedures conducted between 2014 and 2024 at a single tertiary center. Of these, 34 tachycardias (20%) originated from the para-Hisian region. Patient demographics, procedural characteristics, acute outcomes, complications, and arrhythmia-free survival were compared between PHAT and non-PHAT groups. Electrophysiological parameters, including P-wave morphology and intracardiac electrogram timing, were analyzed. Survival analysis was performed using Kaplan–Meier and Cox proportional hazards models.
Results
Patients with PHAT were older than those with other FATs (72.2 ± 12.6 vs. 59.6 ± 18.5 years; p < 0.001). Acute procedural success was achieved in all PHAT cases (34/34). The NCC was the primary ablation site in 31 procedures; in two, additional right atrial septal applications were required. Complications were infrequent (3/34): one transient second-degree AV block, one mild PR interval prolongation, and one femoral pseudoaneurysm. The mean tachycardia cycle length was 475 ± 118 ms, with significantly shorter P-wave duration during tachycardia compared with sinus rhythm (85 ± 26 ms vs. 116 ± 24 ms; p < 0.001) in PHAT cases. Electrogram analysis showed slightly earlier activation in the aortic root than in right atrium parahisian location (−2.35 ms; p = 0.046). At 36 months, no significant differences were observed in arrhythmia recurrence between PHAT and non-PHAT groups (HR 0.5; 95% CI 0.21–1.18; p = 0.11).
Conclusion
Catheter ablation of PHAT via the NCC is a safe and highly effective strategy, achieving a very high acute success with minimal complications and long-term outcomes comparable to other FATs. These findings support the NCC approach as the preferred first-line technique for PHAT ablation, minimizing AV conduction risk while maintaining procedural efficacy.Parahisian AT ablation from NCCFreedom from atrial tachyarrhythmia