Determinants of acute irreversible electroporation lesion characteristics after pulsed field ablation: the role of voltage, contact, and adipose interference

National workflow experience with pulsed field ablation for atrial fibrillation: learning curve, efficiency, and safety

BACKGROUND

Recent data on pulsed field ablation (PFA) for atrial fibrillation (AF) ablation suggest a progressive reduction in procedural times. Real-world data regarding the relationship between the learning curve of PFA and clinical outcomes are scarce. The objective was to evaluate the PFA learning curve and its impact on acute outcomes.

METHODS

Consecutive patients undergoing AF ablation with the FARAPULSE™ PFA system were included in a prospective, non-randomized multicenter study. Procedural times were stratified on the operators' learning curve. Comparative analysis of skin-to-skin time was conducted with radiofrequency (RF) and cryoablation (CB) pulmonary vein isolation (PVI) procedures performed by the same operators in the previous year.

RESULTS

Among 752 patients, 35.1% were females, and 66.9% had paroxysmal AF; mean age was 62.2 ± 10 years. A total of 62.5% of procedures were performed by operators with > 20 PFA procedures. Both time to PVI (25.6 ± 10 min vs 16.5 ± 8, p < 0.0001) and fluoroscopy time (19.8 ± 8 min vs 15.9 ± 8 min, p = 0.0045) significantly improved after 10 associated with consistent linear trend towards procedural time reduction (R2 0.92-0.68 across various procedural metrics). Current PFA skin-to-skin time was lower than the historical skin-to-skin one in 217 (62.4%) procedures; it was similar in 112 (32.2%) cases and higher than the historical skin-to-skin one in 19 (5.5%). No major complications were reported.

CONCLUSIONS

In this nationwide multicentric experience, the novel PFA system proved to be fast, safe, and acutely effective in both paroxysmal and persistent AF patients. The learning curve appears to be rapid, as improvements in procedural parameters were observed after only a few procedures.

CLINICAL TRIAL REGISTRATION

Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA). URL: http://clinicaltrials.gov/ Identifier: NCT05617456.

Pulsed field ablation technology for pulmonary vein and left atrial posterior wall isolation in patients with persistent atrial fibrillation

INTRODUCTION

Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation (PeAF) undergoing left atrial posterior wall isolation (LAPWI).

METHODS

The Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA) prospective registry included consecutive patients referred for PeAF catheter ablation at 9 Italian centers, treated with the FARAPULSETM-PFA system. The primary efficacy and safety study endpoints were the acute LAPWI rate, freedom from arrhythmic recurrences and the incidence of major periprocedural complications. Patients undergoing pulmonary vein isolation (PVI) alone, PWI + LAPWI and redo procedures were compared.

RESULTS

Among 249 patients, 21.7% had long-standing PeAF, 79.5% were male; mean age was 63 ± 9 years. LAPWI was performed in 57.6% of cases, with 15.3% being redo procedures. Median skin-to-skin times (PVI-only 68 [60-90] vs. PVI + LAPWI 70 [59-88] mins) did not differ between groups. 45.8% LAPWI cases were approached with a 3D-mapping system, and 37.3% with intracardiac echocardiography. LAPWI was achieved in all patients by means of PFA alone, in 88.8% cases at first pass. LAPWI was validated either by an Ultrahigh-density mapping system or by recording electrical activity + pacing maneuvers. No major complications occurred, while 2.4% minor complications were detected. During a median follow-up of 273 [191-379] days, 41 patients (16.5%) experienced an arrhythmic recurrence after the 90-day blanking period, with a mean time to recurrence of 223 ± 100 days and no differences among ablation strategies.

CONCLUSION

LAPWI with PFA demonstrates feasibility, rapidity, and safety in real-world practice, offering a viable alternative for PeAF patients. LAPWI is achievable even with a fluoroscopy-only method and does not significantly extend overall procedural times.

'Single-shot' pulmonary vein isolation using a novel lotos pulsed field ablation catheter: a pre-clinical evaluation of feasibility, safety, and 30-day efficacy

AIMS

Pulsed field ablation (PFA) is emerging as a non-thermal, tissue-specific technique for pulmonary vein isolation (PVI) in atrial fibrillation therapy. This pre-clinical study aims to investigate the feasibility and safety of PVI using a novel PFA system including a nanosecond-scale PFA generator, a novel lotos PFA catheter, and a customized 12 Fr steerable sheath.

METHODS AND RESULTS

A total of 11 Yorkshire swine were included in this study, with 4 in the acute cohort and 7 in the chronic cohort. Under general anaesthesia, transseptal puncture and pulmonary vein (PV) angiography was initially performed. The PFA catheter was navigated to position at the right and left PV antrum after the electroanatomic reconstruction of the left atrium. Biphasic PFA applications were performed on PVs in both the spindle-shaped and the lotos-shaped poses. Pulmonary vein isolation and PFA-associated safety were assessed 30 min after ablation in both cohorts and 30 days later in the chronic cohort. Detailed necropsy and histopathology were performed. Additional intracardiac echocardiography and coronary angiogram were evaluated for safety. All target PVs (n = 20) were successfully isolated on the first attempt. No spasm of coronary artery or microbubble was seen during the procedure. Eleven of 12 PVs (91.6%) remained in isolation at the 30-day invasive study. No evidence of PV stenosis was observed in any targets. However, transient diaphragm capture occurred in 17.6%. Histopathological examinations showed no evidence of collateral injury.

CONCLUSION

This study provides scientific evidence demonstrating the safety and efficacy of the novel PFA catheter and system for single-shot PVI, which shows great potential.

Severe acute kidney injury related to haemolysis after pulsed field ablation for atrial fibrillation

AIMS

Pulsed field ablation (PFA) has been proposed as a novel alternative to radiofrequency (RF) and cryoablation in the treatment of atrial fibrillation (AF). Following the occurrence of two cases of acute kidney injury (AKI) secondary to haemolysis after a PFA procedure, we evaluated haemolysis in a cohort of consecutive patients.

METHODS AND RESULTS

Two cases of AKI occurred in last May and June 2023. AKI was secondary to acute and severe haemolysis after a PFA procedure. From June 2023, a total of 68 consecutive patients (64.3 ± 10.5 years) undergoing AF ablation with PFA were enrolled in the study. All patients had a blood sample the day after the procedure for the assessment of haemolysis indicators. The pentaspline PFA catheter was used with a total number of median applications of 64 (54; 76). Nineteen patients (28%) showed significantly depleted haptoglobin levels (<0.04 g/L). A significant inverse correlation was found between the plasma level of haptoglobin and the total number of applications. Two groups were compared: the haemolysis+ group (haptoglobin < 0.04 g/L) vs. the haemolysis- group. The total number of applications was significantly higher in the haemolysis+ group vs the haemolysis - group respectively 75 (62; 127) vs 62 (54; 71) P = 0.011. More than 70 applications seem to have better sensitivity and specificity to predict haemolysis.

CONCLUSION

Intravascular haemolysis can occur after certain procedures of PFA. Acute kidney injury is a phenomenon that appears to be very rare after a PFA procedure. However, caution must be exercised in the number of applications to avoid severe haemolysis.

A real-world case-control study on the efficacy and safety of pulsed field ablation for atrial fibrillation

OBJECTIVE

The primary objective of this study was to evaluate the efficacy and safety of pulsed field ablation in individuals diagnosed with atrial fibrillation.

METHODS

A total of 36 patients diagnosed with atrial fibrillation were enrolled in the pulsed field ablation group, while another 36 patients diagnosed with atrial fibrillation were included in the radiofrequency ablation group. Among the study participants, 15 patients in the pulsed field ablation group and 17 patients in the radiofrequency ablation group had persistent atrial fibrillation. Comprehensive comparisons were made between the two groups, including baseline data, underlying diseases, medication usage, intraoperative parameters, and atrial fibrillation recurrence rates at 1, 3, and 6 months during the postoperative follow-up period.

RESULTS

(1) There were no significant differences observed between the two groups concerning baseline data and antiarrhythmic drug usage (P > 0.05); (2) the effective ablation time for both left and right pulmonary veins in the pulsed field ablation group was markedly shorter compared to the radiofrequency ablation group (P < 0.001 for each vein); (3) within the pulsed field ablation group, the number of discharges, catheter operation time, and effective ablation time for the left pulmonary vein were significantly higher than those for the right pulmonary vein (P < 0.05). Conversely, in the radiofrequency ablation group, the number of discharges for the left pulmonary vein was significantly higher than that for the right pulmonary vein (P < 0.05); and (4) when comparing sinus rhythm maintenance at 1, 3, and 6 months postoperatively, no statistically significant differences were noted between the two groups for paroxysmal, persistent, and paroxysmal + persistent atrial fibrillation cases (P > 0.05).

CONCLUSION

During the 6-month follow-up period, pulsed field ablation demonstrated comparable efficacy to radiofrequency ablation with respect to recurrence rates for both paroxysmal and persistent atrial fibrillation. Moreover, pulsed field ablation exhibited high safety levels, excellent surgical efficiency, and a notably brief learning curve, affirming its viability as a therapeutic option for these conditions.