Focal atrial tachycardia originating from the non-coronary aortic sinus: electrophysiological characteristics and catheter ablation.

OBJECTIVES: We sought to investigate electrophysiological characteristics and catheter ablation in patients with focal atrial tachycardia (AT) originating from the non-coronary aortic sinus (AS). BACKGROUND: In patients with failed ablation of focal AT near the His bundle (HB) region, an origin from the non-coronary AS should be considered because of the close anatomical relationship. METHODS: This study included 9 patients with focal AT, in 6 of whom attempted radiofrequency (RF) ablation had previously failed. Activation mapping was performed during tachycardia to identify an earliest activation in the atria and the AS. The aortic root angiography was performed to identify the origin in the AS before RF ablation. RESULTS: Focal AT was reproducibly induced by atrial pacing. Mapping in atria demonstrated that the earliest atrial activation was located at the HB region, whereas mapping in the non-coronary AS demonstrated that an earliest atrial activation preceded the atrial activation at the HB by 12.2 +/- 6.9 ms and was anatomically located superoposterior to the HB in all 9 patients. Also, His potentials were not found at the successful site in the non-coronary AS in all 9 patients. The focal AT was terminated in <8 s in all 9 patients. Junctional beats and PR prolongation did not occur during RF application in all 9 patients. No complications occurred in any of the nine patients. All 9 patients were free of arrhythmias without antiarrhythmic drugs during a follow-up of 9 +/- 3 months. CONCLUSIONS: In patients with focal AT near the HB region, mapping in the non-coronary AS can improve clinical outcome.