1Deutsches Herzzentrum München Elektrophysiologie München, Deutschland
Introduction
Pulsed-field ablation (PFA) is becoming increasingly relevant in the field of cardiac electrophysiology. Recent studies have demonstrated pulmonary vein isolation (PVI) using a single-shot PFA device to be a sufficient alternative to cryo-ablation or radiofrequency (RF) ablation. Nevertheless, the use of single-shot devices is limited. For this reason, technologies implementing point-by-point PFA are rapidly gaining importance. A commercially available system (CENTAURI™, Galvanize therapeutics, San Carlos, USA) uses RF catheters in combination with a PFA-generator. Data on the use of this technology is sparse, especially for treating atrial tachycardia (AT). The aim of this study was to evaluate acute procedure success, safety and mid-term outcomes of point-by-point PFA in cases of left and right atrial tachycardia.
Methods
Consecutive patients treated with a focal PFA-ablation (N = 34) suffering from atrial tachycardia were included. High density mapping was performed in all patients, using either NavX Ensite X and the Advisor HD-Grid catheter (both Abbott) or Rhythmia and the Orion catheter (both Boston Scientific). Established RF contact-force enabled ablation catheters were employed as PFA catheters (TactiCath/Abbott or StablePoint/Boston Scientific) with the Galaxy system (CENTAURI™, Galvanize therapeutics, San Carlos, USA) using monopolar PFA delivery in accordance the recommended energy setting. The standard ablation protocol for ablation of AT were not changed. If necessary, burst stimulation was performed in order to induce the clinical AT. Acute procedure success was defined as creation of ablation lesions preventing the mechanism of the AT and/or non-inducibility of the clinical AT. Linear lesions were tested by differential pacing; sufficient PVI was proven by entry block. Outcome and safety was evaluated during the hospital stay and visits at our outpatient clinic, including 7d-Holter-ECG.
Results
In all patients, acute procedure success was achieved. Baseline characteristics are listed in table 1. Patients previously had 1,21 ± 0,88 atrial ablation procedures, 67,6% of patients had linear lesions in the past. Mean procedure duration was 102,7 ± 30,3 min, the LA dwell time was 75,0 ± 24,7 min (table 2).
Any desired lesion set was accomplished (PVI, linear lesions or ablation of focal AT/localized reentry) with the focal PFA technology. Linear lesions were ablated in 32 (94,1%) patients, while PVI was performed in 12 patients (35,3%). Ablation of localized reentries was necessary in 2 patients (5,9%). In total, 51 linear lesions were created: 27 anterior lines, 18 roof lines, 5 CTI-lines and one posterior box. Furthermore, three patients suffered a macro-reentry due to reconnected pulmonary veins. An overview of AT termination sites is shown in Figure 1.
No procedure-related minor or major complications occurred (no groin complications, no stroke, no pericardial tamponade). After a mean follow-up of 179,4 ± 107,8 days, 8 patients (23,5%) suffered from recurrences of any atrial recurrence.
Conclusion
Applying focal PFA with well-known RF ablation catheters is safe and efficient in complex cases of atrial tachycardia. Integration of this new system into clinical practice is feasible and did not prolong the procedures. Acute procedure success was achieved in all cases. Larger trial are needed for further evaluation of efficacy and safety, including optimized PFA ablation settings.