Background-Catheter ablation of atrial tachycardia (AT) arising near the coronary cusps has been reported in limited numbers of patients. We investigated the electrophysiological characteristics of these ATs in 22 consecutive patients. Methods and Results-This study included 22 patients (mean ageϮSD, 53Ϯ11 years; 86% female) with ATs arising near the aortic coronary cusps who underwent successful ablation. Activation mapping was performed during tachycardia to identify the earliest activation site. All patients achieved successful ablation through either a retrograde aortic (nϭ19) or a transseptal (nϭ3) approach. The successful ablation sites were located in the noncoronary cusp (NCC) (nϭ16), including 3 near the junction between the NCC and right coronary cusp. The remaining 6 cases were ablated from the left coronary cusp (LCC) (nϭ3) or the left atrium posterior to the LCC (nϭ3). For most tachycardias, there were distinctive P-wave morphological features recorded for each cusp location. Furthermore, analysis of the electrogram morphological features recorded during tachycardia at successful ablation sites revealed an atrial/ventricular (A/V) ratio Ͼ1 in 14 of 16 NCC ATs; the remaining 2, from the NCC near the junction with the right coronary cusp, showed an A/V ratio Յ1. At ablation sites in the LCC, the A/V ratio was Ͻ1 (4 of 6 patients) or 1 (remaining 2 patients). During a follow-up duration of 30Ϯ13 months, all patients were free of arrhythmias without antiarrhythmic drugs. Conclusions-ATs surrounding the aortic coronary cusps can be safely and effectively ablated, with good long-term outcomes. In addition to the P-wave morphological features, the A/V ratio of the local electrogram recording during tachycardia facilitated the localization of successful sites. (Circ Arrhythm Electrophysiol. 2011;4:902-908.)

Background—Focal atrial tachycardias (ATs) surrounding the anterior atrial septum (AAS) have been successfully ablated from the right atrial septum (RAS), the aortic cusps, and the aortic mitral junction. However, the strategy for mapping and ablation of AAS-ATs has not been well defined.Methods and Results—Of 227 consecutive patients with AT, 47 (20.7%; mean age, 56.3±11.6 years) with AAS-ATs were studied; among them, initial ablation was successful at RAS in only 5 of 14 patients and at noncoronary cusp (NCC) in 28 of 33 patients. In 45 of the 47 patients, the 46 of 48 AAS-ATs were eliminated at RAS in 8 patients, NCC in 35 patients (earliest activation time at NCC was later than that at RAS by 5–10 ms in 6 patients), and aortic mitral junction in 3 patients (all with negative P wave in lead aVL and positive P wave in the inferior leads), including 1 patient whose 2 ATs were eliminated separately from the NCC and the aortic mitral junction.Conclusions—Most of the ATs surrounding the AAS can be eliminated from within the NCC, which is usually the preferential ablation site. Ablation at the RAS and aortic mitral junction should be considered when supported by P-wave morphologies on surface ECG and results of activation mapping and ablation.

PM ventricular arrhythmias could be identified from LPF ventricular arrhythmias by calculation of QRS duration combined with Vi/Vt using ECG.