Introduction: Atrial tachycardias (AT) originating from the anteroseptal region of the aortic root, near the atrioventricular node can be challenging to eliminate safely by catheter ablation. In this study, we examine the characteristics of anteroseptal ATs in a cohort of patients at our centers, and demonstrate the long-term efficacy and safety of targeting the arrhythmias from within the base of the noncoronary aortic valve cusp (NCC).
Methods & Results: From among a cohort of 54 patients with symptomatic focal AT undergoing invasive electrophysiological evaluation, the point of earliest right atrial (RA) activation was at the peri-AV nodal region in 10 patients, just postero-superior to the His-bundle. Before further mapping, RA lesions placed in two patients were unsuccessful in eliminating the arrhythmia. Because of its proximity to the interatrial septum, the base of the NCC was mapped using a retrograde aortic approach, and revealed a point of early activation without the presence of a His potential. The arrhythmia terminated with <10 seconds of radiofrequency or cryothermal energy delivery and was successfully eliminated in 7 of 10 patients. Transient termination or acceleration of the AT was noted in the other three patients, prompting successful ablation from a left atrial septal position or a reattempt from a para-Hisian RA position. All patients have been arrhythmia free during follow-up (41 ± 12 months).
Conclusions: Catheter ablation from within the base of the NCC represents a safe and effective means to eliminate focal AT arising from the peri-AV nodal region.