Introduction: Success rates of catheter ablation for paroxysmal AF are close to 80% because of efficacy of pulmonary vein isolation (PVI). In persistent AF, outcomes after PVI alone is worse as the pathophysiology remains unclear. Prolonged AF duration is an independent predictor for worse success rates after catheter ablation. In this study, we investigated efficacy and safety of ablation of dispersions, detected with the VOLTA-system, as additional ablation strategy after PVI in patients with long-standing persistent AF.

Methods: All consecutive patients with long-standing persistent AF treated with the VOLTA algorithm in our institution between 05/21 and 10/22 were included (n = 41, mean age 68.9 ± 10.0 years, baseline characteristics are shown in table 1). The procedure was done with a 3D-mapping system (NavX Ensite X, Abbott or CARTO3, Biosense Webster) using a high-density mapping catheter (HD Grid, Abbott or Pentaray, Biosense Webster) and the VOLTA VX1 system for detection of right and left atrial areas with spatio-temporal dispersion (DISPERS). Ablation of DISPERS was aiming at homogenizing, dissecting, isolating or connecting DISPERS areas to non-conducting structures. Follow-up contained visits at our out-patient-clinic at 1, 3, 6 and 12 months and repetitive 7 day Holter ECGs. Late recurrence (LR) was defined as recurrence after 90 days or as recurrence, which caused further ablation. All complications requiring intervention or causing long-term sequelae were classified as major complications.

Results: In 24/41 pts (58.5%), the DISPERS guided ablation was the first AF ablation. Patients were suffering from very long-standing persistent AF with a mean AF duration of 64.89 ± 54.77 months. Additional to circumferential PVI, ablation of all detected left atrial (100%) and right atrial (68.3%) DISPERS areas was performed, leading to significant slowing of AF cycle length (mean 23.3%) or termination of AF to AT (5/41, 12.2%) or direct conversion to SR (6/41, 14.6%). Using HPSD-ablation in all patients RF-duration was 26.84 ± 10.90 minutes. 



No pericardial tamponade or stroke occurred. One patient (2.4%) suffered a pseudoaneurysm after groin puncture, which resolved without any sequelae after manual compression. Three patients (7.3%) required temporary external pacing due to delayed sinus recovery after the procedure. No patient was in need of permanent pacemaker implantation.
LR occurred in 25 patients (61.0 %) after the first ablation: In 8/25 patients (32 %), LR was solely AF, whereas in 15/25 patients (60%) LR was a left AFlutt. In 2 patients (8%), AF and left AFlutt was detected.
During a follow-up of 231 ± 129 days, 72.9 % of patients remained in sinus rhythm undergoing 1.6 ± 0.68 ablations (s. Figure 1). Additionally, Figure 2 illustrates the AF-free outcome in all patients. At follow-up, two patients (4.9%) were on antiarrhythmic drugs.