Background: The anterior and lateral position of the anterolateral papillary muscle (ALPM) has found to be reached with better catheter stability and less mechanical bumping via the transseptal (TS) compared to the retrograde aortic (RA) approach. Aim: To compare the TS and RA approaches on mapping and ablation of ventricular arrhythmias (VAs) arising from ALPMs. Methods: Thirty-two patients with ALPM-VAs undergoing mapping and ablation via the TS approach were included and compared with 31 patients via the RA approach within the same period. Acute success was compared, as well as other outcomes including misinterpreted mapping results due to bumping, radiofrequency (RF) attempts, procedural time and success rate at 12 months’ follow-up. Results: Acute success was achieved in more cases in the TS group (96.4% vs 72.0%, P=0.020). During activation mapping, bump-provoked premature ventricular complexes (PVCs) misinterpreted as clinical PVCs were more common in the RA group (30.0% vs 58.3%, P=0.036), leading to more RF attempts (3.5±2.7 vs 7.2±6.8, P=0.006). Suppression of VAs were finally achieved in the unsuccessful cases by changing to the alternative approach, but the procedural time was significantly less in the TS group (90.0±33.0 vs 113.7±41.1min, P=0.027) with less need to change the approach, although follow-up success rates were similar (75.0% vs 71.0%, P=0.718). Conclusion: A TS rather than RA approach as the initial approach appears to facilitate mapping and ablation of ALPM-VAs, specifically by decreasing the possibility of misleading mapping results caused by bump-provoked PVC, and increase the acute success rate thereby.

Abstract Introduction: Linear ablation in addition to pulmonary vein antrum isolation (PVAI) has failed to improve the success rate for persistent atrial fibrillation (PeAF), due to incomplete block of ablation lines, especially in the mitral isthmus (MI). Methods and results: The study enrolled 191 patients (66 in group 1 and 125 in group 2). In group 1, EI-VOM was firstly performed, followed by radiofrequency (RF) applications targeting bilateral PVAI and bidirectional block in the roofline, cavotricuspid isthmus, and MI. In group 2, PVAI and the three linear ablations were completed using only RF energy. MI block was achieved in 63(95.5%) and 101(80.8%) patients in group 1 and 2, respectively (p=0.006). Patients in group 1 had shorter ablation time for left pulmonary vein antrum (8.15 min vs 12.59 min, p<0.001) and MI (7.0 min vs 11.8 min, p<0.001) and required less cardioversion (50(78.5%) vs 113(90.4%), p=0.007). During the 12-month follow-up, 58 (87.9%) patients were free from AF/AT in group 1 compared with 81 (64.8%) in group 2 (p<0.001). In multivariate cox regression, the ‘upgraded 2C3L’ procedure is associated with a lower recurrence rate (HR 0.27, 95%CI 0.12-0.59). Conclusion: Compared with the conventional ‘2C3L’ approach, the ‘upgraded 2C3L’ approach has higher effectiveness for ablation of PeAF.