Pulsed-field ablation-based pulmonary vein isolation: acute safety, efficacy and short-term follow-up in a multi-center real world scenario

Safety and efficacy of pulsed-field ablation for atrial fibrillation in the elderly: A EU-PORIA sub-analysis

BACKGROUND

The role of catheter ablation in elderly patients with atrial fibrillation (AF) is unclear. Pulsed field ablation (PFA) demonstrates a favorable clinical profile, however, data on elderly patients are lacking.

AIMS

We aimed to assess the safety and efficacy of PFA in the elderly, using data from the EU-PORIA registry.

METHODS

Periprocedural complications and long-term safety and efficacy outcomes of AF ablation using the pentaspline PFA catheter (Farapulse™) were compared between patients older than 80 years old and their younger counterparts, across seven European centers.

RESULTS

Among the 1233 patients in the registry, 88 (7.1 %) were older than 80 years. Elderly patients were more often females (51.1 % vs 37.8 %, p = 0.01) with a lower median BMI (26.0, IQR:23.5-29.2 vs 26.9, IQR:24.4-30.4 kg/m2, p = 0.02), a higher median CHA2DS2-VASc score (4, IQR:3-5 vs 2, IQR:1-3, p < 0.001) and a higher incidence of hypertension (73.9 % vs 52.7 %, p < 0.001). In both groups, most patients had paroxysmal AF (58.0 % vs 60.3 %, p = 0.65). Ablation in the elderly was more frequently performed with minimally interrupted anticoagulation (87.5 % vs 59.7 %, p < 0.001). Despite comparable rates of overall complications (5.7 % vs 3.5 %, p = 0.29), elderly patients had a higher incidence of stroke (2.3 % vs 0.3 %, p = 0.04). At 12 months, major adverse clinical events (4.5 % vs. 2.1 %, p = 0.12) and arrhythmia-free survival (70 % vs 74 %, p = 0.69) were comparable in both groups. None of the recurrence-free elderly patients were on antiarrhythmic drugs at the end of follow-up.

CONCLUSION

In this real-world cohort, the efficacy of PFA for AF was similar in elderly and younger patients. Despite comparable complication rates, a higher incidence of stroke was observed in the elderly.

Pulsed Field Ablation to Treat Paroxysmal Atrial Fibrillation: Safety and Effectiveness in the AdmIRE Pivotal Trial

BACKGROUND

Evidence from clinical trials of early pulsed field ablation (PFA) systems in treating atrial fibrillation has demonstrated their promising potential to reduce complications associated with conventional thermal modalities while maintaining efficacy. However, the lack of a fully integrated mapping system, a staple technology of most modern electrophysiology procedures, poses limitations in lesion creation and workflow options. A novel variable-loop PFA catheter integrated with an electroanatomic mapping system has been developed that allows for real-time nonfluoroscopic procedural guidance and lesion indexing as well as feedback of tissue-to-catheter proximity. AdmIRE (Assessment of Safety and Effectiveness in Treatment Management of Atrial Fibrillation With the Bosense-Webster Irreversible Electroporation Ablation System), a multicenter, single-arm, Food and Drug Administration investigational device exemption study, evaluated the long-term safety and effectiveness of this integrated PFA system in a large United States-based drug-refractory symptomatic paroxysmal atrial fibrillation patient population.

METHODS

Using the PFA catheter with a compatible electroanatomic mapping system, patients with drug-refractory symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation. The primary safety end point was primary adverse event within 7 days of ablation. The primary effectiveness end point was a composite end point that included 12-month freedom from documented atrial tachyarrhythmia (ie, atrial fibrillation, atrial tachycardia, atrial flutter) episodes, failure to achieve pulmonary vein isolation, use of a nonstudy catheter for pulmonary vein isolation, repeat procedure (except for one redo during blanking), taking a new or previously failed class I or III antiarrhythmic drug at higher dose after blanking, or direct current cardioversion after blanking.

RESULTS

At 30 centers, 277 patients with paroxysmal atrial fibrillation (61.5±10.3 years of age; 64.3% male) in the pivotal cohort underwent PFA. More than 25% of the procedures were performed without fluoroscopy. Median (Q1, Q3) pulmonary vein isolation procedure, fluoroscopy, and transpired PFA application times were 81.0 (61.0, 112.0), 7.1 (0.00, 14.3), and 31.0 (24.8, 40.9) minutes, respectively. The primary adverse event rate was 2.9% (8 of 272), with the most common complication being pericardial tamponade. The 12-month primary effectiveness end point was 74.6%. The 1-year freedom from atrial fibrillation, atrial tachycardia, or atrial flutter recurrence rate after blanking was 75.4%. Substantial improvements in quality of life were observed as early as 3 months after the procedure, concurrent with a reduction in multiple health care use measures.

CONCLUSIONS

AdmIRE confirmed the safety and effectiveness of the variable-loop PFA catheter, with short procedure and PFA application times and low fluoroscopy exposure.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05293639.

Characterization and Clinical Significance of Hemolysis After Pulsed Field Ablation for Atrial Fibrillation: Results of a Multicenter Analysis

BACKGROUND

Pulsed field ablation (PFA) is increasingly used in clinical practice for the treatment of atrial fibrillation. While the susceptibility of erythrocytes to electroporation is well established, the effect of cardiac PFA technologies on hemolysis has remained underreported. The aim of this study was to investigate the incidence, severity, and clinical impact of PFA-induced hemolysis.

METHODS

We included n=145 patients undergoing atrial fibrillation catheter ablation with a pentaspline PFA catheter (biphasic, bipolar pulses of 2 kV) and n=70 patients receiving radiofrequency ablation (40-90 W) at 4 high-volume European centers. The lesion set comprised pulmonary vein isolation for paroxysmal atrial fibrillation and pulmonary vein isolation±additional lesions for persistent atrial fibrillation. Hemolysis and renal function biomarkers were analyzed in blood samples at baseline, at the end of ablation, and 24 hours after the procedure.

RESULTS

Baseline characteristics were well balanced between groups (overall mean 65.7±9.4 years; 69.3% men). The ablation procedures comprised a mean of 61.6±27.4 PFA deliveries and 26.3±15.0 minutes RF duration. Hemolysis was detected in 94.3% versus 6.8% of patients after PFA versus radiofrequency ablation (P<0.001): PFA was associated with significantly lower haptoglobin levels (0.5±0.4 versus 1.0±0.4 g/L), while free plasma hemoglobin (592.8±330.6 versus 147.8±183.0 mg/L), bilirubin (21.3±11.3 versus 14.8±8.8 µmol/L), and LDH (lactate dehydrogenase, 352.7±115.7 versus 253.2±56.5 U/L) were significantly higher after PFA compared with radiofrequency ablation (all P<0.001). Hemolysis correlated with the number of PFA deliveries (r=0.62 [95% CI, 0.33-0.80]; P<0.001), with the highest severity occurring ≥54 PFA deliveries. After PFA, hemoglobinuria occurred in 36.4%, while creatinine increase was higher in patients with baseline glomerular filtration rate <50 mL/min than with baseline glomerular filtration rate >50 mL/min (Δcrea, 27.0±103.1 versus -0.2±12.1 µmol/L; P=0.010).

CONCLUSIONS

Intravascular hemolysis is a frequent finding after PFA and increases with the number of PFA deliveries. Until the clinical impact of PFA-associated hemolysis is fully elucidated, a careful titration of PFA deliveries during the ablation procedure is warranted.

Pulsed-field- vs. cryoballoon-based pulmonary vein isolation: lessons from repeat procedures

AIMS

Pulsed-field ablation (PFA) is an emerging technology to perform pulmonary vein isolation (PVI). Initial data demonstrated high safety and efficacy. Data on long-term PVI durability and reconduction patterns in comparison to established energy sources for PVI are scarce. We compare findings in repeat ablation procedures after a first PFA to findings in repeat ablation procedures after a first cryoballoon ablation (CBA) based PVI.

METHODS AND RESULT

A total of 550 consecutively enrolled patients underwent PFA or CBA index PVI. Repeat ablations in patients with symptomatic atrial arrhythmia recurrences were analysed. A total of 22/191 (12%) patients after index PFA-PVI and 44/359 (12%) after CBA-PVI underwent repeat ablation. Reconduction of any pulmonary vein (PV) was detected by multipolar spiral mapping catheter at each PV with careful evaluation of PV potentials and by 3D-mapping in 16/22 patients (73%) after PFA-PVI and in 33/44 (75%) after CBA-PVI (P = 1.000). Of 82 initially isolated PVs after PFA-PVI, 31 (38%) were reconducting; of 169 isolated PVs after CBA-PVI, 63 (37%) were reconducting (P = 0.936). Clinical atrial tachycardia occurred similarly in patients after PFA (5/22; 23%) and CBA (7/44; 16%; P = 0.515). Roof lines were set more often after PFA- (8/22; 36%) compared with CBA-PVI (5/44; 11%; P = 0.023). Repeat procedure duration [PFA: 87 (76, 123) min; CBA: 93 (75, 128) min; P = 0.446] was similar and fluoroscopy time [PFA: 11 (9, 14) min; CBA: 11 (8, 14) min; P = 0.739] equal between groups at repeat ablation.

CONCLUSION

During repeat ablation after previous PFA- or CBA-based PVI, electrical PV-reconduction rates and patterns were similar.

Meta-analysis of Pulsed Field Ablation Versus Thermal Ablation for Pulmonary Vein Isolation in AF: A Broad Overview Focusing on Efficacy, Safety and Outcomes

The recently established non-thermal, single-shot pulsed field ablation (PFA) is a potential tool for achieving rapid pulmonary vein isolation (PVI) to cause cell death by electroporation, yet data regarding this state-of-the-art technology remain sparse. In this meta-analysis, we included 3,857 patients from 20 studies. There was no significant difference in AF recurrence between the PFA and control groups. Subgroup analysis showed that additional ablation beyond PVI has a similar rate of AF recurrence to PVI alone (10% versus 13%, respectively). PVI durability was achieved in 83% (mean), 95% CI [65-99%] of the PFA group and in 79% (mean), 95% CI [60-98%] of the control group, with no significant difference in the rate of PVI durability between the two groups. The PFA group had considerably reduced procedure duration, but not fluoroscopy time. No statistically significant differences in periprocedural complications were observed. PFA is associated with shorter procedural time than thermal ablation. Cardiac complications were uncommon and mainly reversible in both the PFA and control groups.

Preclinical evaluation of reversible pulsed electrical field: electrophysiological and histological assessment of myocardium

Background

Pulsed field ablation, as a non-thermal ablation modality, has received increasing attention. The aim of this study is to explore whether a reversible pulsed electric field (RPEF) can temporarily inhibit electrical conduction and provide a novel method for precise ablation of arrhythmia.

Methods

RPEF energy was delivered from an ablation catheter to the atrium of six dogs, followed by a series of electrogram and histology assessments.

Results

RPEF ablation of ordinary myocardium resulted in an average reduction of 68.3% (range, 53.7%-83.8%) in electrogram amplitude, while 5 min later, the amplitude in eight electrograms returned to 77.9% (range, 72.4%-87.3%) of baseline. Similarly, the amplitude of the sinoatrial node electrograms reduced by an average of 73.0% (range, 60.2%-84.4%) after RPEF ablation, but recovered to 84.9% (range, 80.3%-88.5%) of baseline by 5 min. No necrotic change was detected in histopathology. Transient third-degree atrioventricular block occurred following the ablation of the maximum His potential sites with RPEF, the duration of which was voltage dependent. The histopathological results showed necrosis of the myocardium at the ablation sites but no injury to His bundle cells.

Conclusions

RPEF can be applied to transiently block electrical conduction in myocardial tissues contributing to precise ablation.

Impact of Pulsed Electric Field Ablation on His Bundle Conduction: A Preclinical Canine Study

BACKGROUND Pulsed field ablation (PFA), as a non-thermal ablation modality, has received increasing attention. The aim of this study was to evaluate the effect of PFA upon His bundle via its implementation with different voltages on the maximum His bundle potential in canines, providing scientific basis for clinical application. MATERIAL AND METHODS Pulsed electrical field energy was delivered from a ablation catheter to the maximum His potential of 7 dogs, followed by a series of electrogram and histology assessments. RESULTS The baseline AH and HV intervals were 55.3±3.7 ms (range, 53.0-59.0 ms), and 34.9±1.3 ms (range, 34.0-36.0 ms), respectively, which were elevated to 65.0±5.4 ms (range, 59.0-70.0 ms) and 35.7±2.7 ms (range, 34.0-37.0 ms) after PFA. Before ablation and immediately after the recovery of third-degree AVB, the AH interval was prolonged (P<0.05) while the HV interval remained unchanged (P>0.05). After ablation, all 7 canines experienced transient third-degree AVB, with a voltage-dependent duration. Masson staining results revealed no apparent damage in His bundle cells. CONCLUSIONS Within a certain voltage range of pulse electric field, ablation of the maximum His potential in canines can result in transient third-degree AVB, providing a new route for guiding safe ablation of para-Hisian arrhythmia.

VARIPULSE: A step-by-step guide to pulmonary vein isolation

INTRODUCTION

The VARIPULSE™ variable-loop circular catheter (VLCC) is a bidirectional, multielectrode catheter that can perform electrophysiological mapping and deliver pulsed field energy through the TRUPULSE™ Generator for the treatment of atrial fibrillation. This ablation system, including the CARTO 3™ three-dimensional electroanatomical mapping system, represents a fully integrated system.

METHODS

Pulsed field ablation (PFA) is a novel, primarily cardiac tissue-selective ablation technology with a minimal thermal effect, potentially eliminating the collateral tissue damage associated with radiofrequency ablation or cryoablation. Integration of a mapping system may lead to shorter fluoroscopy times and improve the usability of the system, allowing tracking of energy density and placement to confirm no areas around the vein are left untreated.

RESULTS

This step-by-step review covers patient selection, mapping, the step-by-step ablation workflow, details on catheter repositioning and ensuring contact, considerations for ablation of specific anatomical variations, and discussion of ablation without fluoroscopy based on our initial clinical experience.

CONCLUSIONS

The VLCC is part of the fully integrated PFA system designed for pulmonary vein isolation, using mapping to guide catheter placement and lesion set creation. The current workflow, which is based on our initial clinical experience, may be further refined as the PFA system is used in real-world settings.

Feasibility study on atrial fibrillation ablation with pulsed field ablation and concomitant occlusion of the left atrial appendage

AIMS

Atrial fibrillation (AF) ablation and left atrial appendage occlusion (LAAO) are increasingly performed as individual procedures. Pulsed field ablation (PFA) has significantly reduced procedure duration and may be advantageous for the combined approach.

METHODS AND RESULTS

We have launched a programme for simultaneous AF ablation using PFA and LAAO for patients qualifying for both treatments and excluding those with a complex anatomy. We compare procedure duration and fluoroscopy time against individual procedures (either AF ablation or LAAO alone), all performed by the same operators and using consistent technologies. We performed the combined procedure in 10 patients (50% males; median age 70 years) and excluded 2 patients (17%) because of a complex left atrial appendage anatomy. No death, stroke, or major bleeding events, including pericardial effusion, occurred. For single-procedure comparison, 207 AF ablation procedures and 61 LAAO procedures were available. The total median procedure duration was 79 min (range 60-125) for the combined procedure, 71 min (25-241) for individual AF ablation (51 min without and 78 min with 3-dimensional electroanatomic mapping), and 47 min (15-162) for individual LAAO. The respective fluoroscopy times were 21 (15-26), 15 (5-44), and 10 (3-50) min. For the combined procedure, femoral vein access to last PFA application lasted 49 min (34-93) and LAAO added 20 min (15-37).

CONCLUSION

Simultaneous PFA-based AF ablation and LAAO in carefully selected patients is feasible and safe and can be executed within a short overall procedure duration.

The Feasibility, Safety and Outcome of Very High-Power Short Duration Radiofrequency Ablation in Pulmonary Vein Isolation: A Real-World Observation Study

Background

Pulmonary vein isolation (PVI) ablation is the established gold standard therapy for patients with symptomatic drug refractory atrial fibrillation (AF). Advancements in radiofrequency (RF) ablation, have led to the development of the novel contact force-sensing temperature-controlled very high-power short-duration (vHPSD) RF ablation. This setting delivers 90 W for up to 4 seconds with a constant irrigation flow rate of 8 mL/min. The aim of this study was to compare procedural outcomes and safety with conventional radiofrequency ablation.

Methods

An observational study was conducted with patients who underwent first time PVI ablation between August 2020 and January 2022. The cohort was divided into: (1) vHPSD ablation; (2) High-power short duration (HPSD) ablation; (3) THERMOCOOL SMARTTOUCH™ SF (STSF). The vHPSD ablation group was prospectively recruited while the HPSD and STSF group were retrospectively collected. Primary outcomes were procedural success, PVI duration, ablation duration and incidence of perioperative adverse events. Secondary outcomes were intraprocedural morphine and midazolam requirement.

Results

A total of 175 patients were included in the study with 100, 30 and 45 patients in the vHPSD, HPSD and STSF group, respectively. PVI was successfully attained in all vHPSD patients. vHPSD demonstrated significantly reduced time required for PVI and total energy application in comparison to the HPSD and STSF groups (67.7 ± 29.7 vs. 92.9 ± 25.7 vs. 93.6 ± 29.1 min, p < 0.0001; 9.87 ± 4.16 vs. 33.9 ± 7.49 vs. 36.0 ± 10.5 min, p < 0.0001, respectively). Intravenous morphine and midazolam requirement was lower in the vHPSD group compared to the HPSD and STSF groups (10.2 ± 3.43 vs. 16.1 ± 4.58 vs. 15.3 ± 3.94 mg, p < 0.0001; 4.04 ± 3.24 vs. 8.63 ± 5.22 vs. 8.58 ± 4.72 mg, p < 0.0001). One cardiac tamponade was observed in both the vHPSD and HPSD groups while the STSF group exhibited an embolic stoke and two pericardial effusions that did not require drainage.

Conclusions

In this study, vHPSD demonstrated a comparable safety profile to the other treatment arms. Procedural duration and energy application time was substantially reduced along with sedation requirement notwithstanding the limitations of observational study design, these preliminary findings are promising with respect to periprocedural outcomes and safety of vHPSD however longitudinal outcomes will be essential to assessing the overall efficacy of this novel technology.

Procedural efficiency is enhanced combining the pentaspline pulsed field ablation catheter with three-dimensional electroanatomical mapping system for pulmonary vein isolation

BACKGROUND

Pulsed field ablation (PFA) offers a safe, non-thermal alternative for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Currently, the pentaspline PFA-system relies heavily on fluoroscopy for catheter manipulation, which poses challenges due to the complexity of left atrium anatomy. Incorporating three-dimensional electroanatomical mapping (3D-EAM) could improve procedural efficiency reducing dependency on fluoroscopy guidance. This study aims to evaluate the effects of integration of 3D-EAM with PFA during PVI.

METHODS

Between September 2022 and December 2023, we retrospectively enrolled 248 patients with paroxysmal or persistent AF undergoing PVI at our center using the pentaspline PFA catheter. The control group (n = 104) received conventional PFA with fluoroscopic guidance alone, while the intervention group (n = 144) underwent PVI with PFA with 3D-EAM integration. Primary outcomes were procedural time, fluoroscopy time (FT), and dose area product (DAP). Secondary endpoints included acute procedural success and incidence of periprocedural complications.

RESULTS

In the 3D-EAM-PFA group, procedural time was 63.3 ± 14.3 min, compared to 65.6 ± 14.9 min in the control group (p = 0.22). The 3D-EAM group experienced significantly reduced FT (9.7 ± 4.4 min vs. 16.7 ± 5.2 min) and DAP (119.2 ± 121.7 cGycm2 vs. 338.7 ± 229.9 cGycm2) compared to the control group, respectively (p < 0.001). Acute procedural success was achieved in all cases. No major complications were observed in either group.

CONCLUSION

Integration of 3D-EAM with the pentaspline PFA catheter for PVI in AF treatment offers a promising approach, with significantly reduced fluoroscopy exposure without compromising procedural time and efficacy.

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.

Pulmonary Vein Isolation with Pulsed Field Ablation and Size-Adjustable Cryo-Balloon: A Comparative Procedural Analysis of First-Time Use

Background: Pulmonary vein isolation (PVI) is the standard of care for the treatment of symptomatic atrial fibrillation (AF). Novel techniques for PVI are the thermal size-adjustable cryo-balloon (CB) system and non-thermal pulsed field ablation (PFA) system. There are currently no data available for a direct comparison between these two systems. Furthermore, with new techniques, it is important to ensure a high level of efficiency and safety during treatment right from initial use. Therefore, the aim of this study was to directly compare the procedural data and safety of these two new PVI techniques in first-time users. Methods: We conducted a single-center prospective study involving 100 consecutive patients with symptomatic atrial fibrillation who underwent first-time PVI using either size-adjustable CB PVI or PFA PVI from July 2023 to March 2024. Results: Acute PVI was achieved in 100% of patients in both groups. First-pass isolation (FPI) was more frequently achieved in the PFA group compared to the size-adjustable CB group. The mean procedural duration and fluoroscopy dose were significantly shorter in the PFA cohort (p < 0.001). Furthermore, a significant reduction in fluoroscopy time was observed during the learning curve within the PFA group (p = 0.023). There were no major complications in both groups. Conclusions: Both systems demonstrate good effectiveness and safety during PVI performed by first-time users. However, the PFA group exhibited a significantly shorter procedural duration.

Pulsed field ablation with the pentaspline catheter compared with cryoablation for the treatment of paroxysmal atrial fibrillation in the UK NHS: a cost-comparison analysis

OBJECTIVES

Pulsed field ablation (PFA) is a promising new ablation modality for the treatment of atrial fibrillation (AF) that has recently become available in the UK National Health Service (NHS). We provide the first known economic evaluation of the technology.

METHODS

A cost-comparison model was developed to compare the expected 12-month costs of treating AF using the pentaspline PFA catheter compared with cryoablation for a single hypothetical patient. Model parameters were based on a recent cost-effectiveness analysis by the National Institute for Health and Care Excellence where possible or published literature otherwise. Deterministic sensitivity, scenario and threshold analyses were conducted.

RESULTS

Costs for a single patient treated with PFA were -3% (-£343) less over 12 months than those who received treatment with cryoablation. PFA was associated with 16% higher catheter costs but repeat ablation costs were over 50% less, driven by a reduction in repeat ablations required. Costs of managing complications were -£211 less in total for PFA compared with cryoablation.

CONCLUSIONS

Routine adoption of PFA with the pentaspline PFA catheter looks to be as affordable for the NHS as current treatment alternative cryoablation.

Pulsed Field Ablation for Atrial Fibrillation: Mechanisms, Advantages, and Limitations

Pulsed field ablation with irreversible electroporation for the treatment of atrial fibrillation involves tissue-specific and non-thermal energy-induced cell necrosis, which helps avoid complications, such as pulmonary vein stenosis, atrial collateral tissue damage, and extensive atrial structural damage, often encountered with traditional thermal ablation. In existing clinical trials, pulsed field ablation has shown excellent effects on pulmonary vein isolation in patients with paroxysmal and persistent atrial fibrillation. Pulsed field ablation is easy, simple, and quick and can reduce iatrogenic injury. Therefore, the application of pulsed field ablation technology in the treatment of atrial fibrillation has a promising future. Notably, the adjustment of parameters in pulsed field ablation with different ablation catheter systems can strongly affect the area and depth of the necrotic myocardium, which greatly affects the likelihood of atrial fibrillation recurrence and incidence of adverse complications after ablation. In this paper, we review the mechanisms, advantages, and limitations of pulsed field ablation based on the results of a series of previous studies and provide ideas and directions for future research.

Procedural performance and outcome after pulsed field ablation for pulmonary vein isolation: comparison with a reference radiofrequency database

Aims

Pulsed field ablation (PFA) is a promising ablation technique for pulmonary vein isolation (PVI) with appealing advantages over radiofrequency (RF) including speed, tissue selectivity, and the promise of enhanced durability. In this study, we determine the procedural performance, efficacy, safety, and durability of PFA and compare its performance with a dataset of optimized RF ablation.

Methods and results

After propensity score matching, we compared 161 patients who received optimized RF-guided PVI in the PowerPlus study (CLOSE protocol) with 161 patients undergoing PFA-guided PVI for paroxysmal or persistent atrial fibrillation (AF; pentaspline basket catheter). The median age was 65 years with 78% paroxysmal AF in the PFA group (comparable characteristics in the RF group). Pulsed field ablation-guided PVI was obtained in all patients with a procedure time of 47 min (vs. 71 min in RF, P < 0.0001) and a fluoroscopy time of 15 min (vs. 11 min in RF, P < 0.0001). One serious adverse event [transient ischaemic attack] occurred in a patient with thrombocytosis (0.6 vs. 0% in RF). During the 6-month follow-up, 24 and 27 patients experienced a recurrence with 20 and 11 repeat procedures in the PFA and the RF groups, respectively (P = 0.6 and 0.09). High-density mapping revealed a status of 4 isolated veins in 7/20 patients in the PFA group and in 2/11 patients in the RF group (35 vs. 18%, P = 0.3).

Conclusion

Pulsed field ablation fulfils the promise of offering a short and safe PVI procedure, even when compared with optimized RF in experienced hands. Pulmonary vein reconnection is the dominant cause of recurrence and tempers the expectation of a high durability rate with PFA.

Characterization of durability and reconnection patterns at time of repeat ablation after single-shot pulsed field pulmonary vein isolation

BACKGROUND

Pulsed field ablation (PFA) is a novel method of cardiac ablation where there is insufficient knowledge on the durability and reconnection patterns after pulmonary vein isolation (PVI). The aim of this study was to characterize the electrophysiological findings at time of repeat procedure in real-world atrial fibrillation (AF) patients.

METHODS

Patients who underwent a repeat procedure (n=26) for symptomatic recurrent arrhythmias after index first-time treatment with single-shot PFA PVI (n=266) from July 2021 to June 2023 were investigated with 3D high-density mapping and ad-hoc re-ablation by radiofrequency or focal PFA.

RESULTS

Index indication for PVI was persistent AF in 17 (65%) patients. The mean time to repeat procedure was 292 ± 119 days. Of the 26 patients (104 veins), complete durable PVI was observed in 11/26 (42%) with a durable vein isolation rate of 72/104 (69%). Two patients (8%) had all four veins reconnected. The posterior wall was durably isolated in 4/5 (80%) of the cases. The predominant arrhythmia mechanism was AF in 17/26 (65%) patients and regular atrial tachycardia (AT) in 9/26 (35%). Reconnection was observed 9/26 (35%) in right superior, 11/26 (42%) in right inferior, 7/26 (27%) in left superior, 5/26 (19%) in left inferior, p=0.31 between veins. The gaps were significantly clustered in the right-sided anterior carina compared to other regions (P=0.009).

CONCLUSIONS

Durable PVI was observed in less than half of the patients at time of repeat procedure. No significant difference in PV reconnection pattern was observed, but the gap location was preferentially located at the anterior aspects of the right-sided PVs. Predominant recurrence was AF. More data is needed to establish lesion formation and durability and AT circuits after PFA.

Pulsed Field Ablation of Atrial Fibrillation: An Initial Australian Single-Centre Experience

BACKGROUND

Pulsed field ablation (PFA) is a newer ablation energy source with the potential to reduce complications and improve efficacy compared to conventional thermal atrial fibrillation (AF) ablation. This study aimed to present an initial single-centre Australian experience of PFA for AF ablation.

METHODS

Initial consecutive patients undergoing PFA for paroxysmal or persistent AF at a single centre were included. Baseline patient characteristics, procedural data and clinical outcomes were collected prospectively at the time of the procedure. Patients were followed up at 3 months and 6-monthly thereafter.

RESULTS

In total, 100 PFA procedures were performed in 97 patients under general anaesthesia. All pulmonary veins (403 of 403) were successfully isolated acutely. Median follow-up was 218 days (range, 16-343 days), and the Kaplan-Meier estimate for freedom from atrial arrhythmias at 180 days was 87% (95% confidence interval 79%-95%). Median procedure time was 74 minutes (range, 48-134 minutes). Median fluoroscopy dose-area product was 345 μGym2 (interquartile range, 169-685 μGym2). Two (2%) pseudoaneurysm vascular access complications occurred. There were no cases of thromboembolic complications, stroke, phrenic nerve palsy, pulmonary vein stenosis, atrio-oesophageal fistula, or pericardial tamponade.

CONCLUSIONS

Pulsed field ablation can be performed safely and efficiently, with encouraging efficacy in early follow-up. Further data and clinical trials will be required to assess the comparative utility of PFA in contemporary AF ablation practice.

Effects of Contact Force on Lesion Size During Pulsed Field Catheter Ablation: Histochemical Characterization of Ventricular Lesion Boundaries

BACKGROUND

Effects of contact force (CF) on lesion formation during pulsed field ablation (PFA) have not been well validated. The purpose of this study was to determine the relationship between average CF and lesion size during PFA using a swine-beating heart model.

METHODS

A 7F catheter with a 3.5-mm ablation electrode and CF sensor (TactiCath SE, Abbott) was connected to a PFA system (CENTAURI, Galvanize Therapeutics). In 5 closed-chest swine, biphasic PFA current was delivered between the ablation electrode and a skin patch at 40 separate sites in right ventricle (28 Amp) and 55 separate sites in left ventricle (35 Amp) with 4 different levels of CF: (1) low (CF range of 4-13 g; median, 9.5 g); (2) moderate (15-30 g; median, 21.5 g); (3) high (34-55 g; median, 40 g); and (4) no electrode contact, 2 mm away from the endocardium. Swine were sacrificed at 2 hours after ablation, and lesion size was measured using triphenyl tetrazolium chloride staining. In 1 additional swine, COX (cytochrome c oxidase) staining was performed to examine mitochondrial activity to delineate reversible and irreversible lesion boundaries. Histological examination was performed with hematoxylin and eosin and Masson trichrome staining.

RESULTS

Ablation lesions were well demarcated with triphenyl tetrazolium chloride staining, showing (1) a dark central zone (contraction band necrosis and hemorrhage); (2) a pale zone (no mitochondrial activity and nuclear pyknosis, indicating apoptosis zone); and a hyperstained zone by triphenyl tetrazolium chloride and COX staining (unaffected normal myocardium with preserved mitochondrial activity, consistent with reversible zone). At constant PFA current intensity, lesion depth increased significantly with increasing CF. There were no detectable lesions resulting from ablation without electrode contact.

CONCLUSIONS

Acute PFA ventricular lesions show irreversible and reversible lesion boundaries by triphenyl tetrazolium chloride staining. Electrode-tissue contact is required for effective lesion formation during PFA. At the same PFA dose, lesion depth increases significantly with increasing CF.

Epicardial Pulsed Field Ablation of Ganglionated Plexi: Computational and Pre-Clinical Evaluation of a Bipolar Sub-Xiphoid Catheter for the Treatment of Atrial Fibrillation

Epicardial pulsed field ablation (PFA) of ganglionated plexi (GPs) is being explored as a potential treatment for atrial fibrillation. Initial work using open-chest access with a monopolar ablation device has been completed. This study describes the early development work for a device that can be used with subxiphoid access and deliver bipolar ablation pulses. Electric field computational models have been used for the initial guidance on pulse parameters. An in vivo assessment of these ablation parameters has been performed in an open-chest canine study, while subxiphoid access and navigation of the device has been demonstrated in a porcine model. Results from this acute study have demonstrated the promising potential of this approach.

Atrial Fibrillation Ablation: Current Practice and Future Perspectives

Catheter ablation to perform pulmonary vein isolation (PVI) is established as a mainstay in rhythm control of atrial fibrillation (AF). The aim of this review is to provide an overview of current practice and future perspectives in AF ablation. The main clinical benefit of AF ablation is the reduction of arrhythmia-related symptoms and improvement of quality of life. Catheter ablation of AF is recommended, in general, as a second-line therapy for patients with symptomatic paroxysmal or persistent AF, who have failed or are intolerant to pharmacological therapy. In selected patients with heart failure and reduced left-ventricular fraction, catheter ablation was proven to reduce all-cause mortality. Also, optimal management of comorbidities can reduce AF recurrence after AF ablation; therefore, multimodal risk assessment and therapy are mandatory. To date, the primary ablation tool in widespread use is still single-tip catheter radiofrequency (RF) based ablation. Additionally, balloon-based pulmonary vein isolation (PVI) has gained prominence, especially due to its user-friendly nature and established safety and efficacy profile. So far, the cryoballoon (CB) is the most studied single-shot device. CB-based PVI is characterized by high efficiency, convincing success rates, and a beneficial safety profile. Recently, CB-PVI as a first-line therapy for AF was shown to be superior to pharmacological treatment in terms of efficacy and was shown to reduce progression from paroxysmal to persistent AF. In this context, CB-based PVI gains more and more importance as a first-line treatment choice. Non-thermal energy sources, namely pulsed-field ablation (PFA), have garnered attention due to their cardioselectivity. Although initially applied via a basket-like ablation tool, recent developments allow for point-by-point ablation, particularly with the advent of a novel lattice tip catheter.

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.

The promise of pulsed field ablation and the challenges ahead

For many years, guidelines have suggested thermal ablation for the treatment of atrial fibrillation. Thermal ablation involves the destruction of tissue, leading to multiple complications. This ablation technique has been tried and tested, however, newer techniques are being investigated in order to avoid these complications. Pulsed field ablation, a nonthermal method of tissue ablation, is being explored as a more safe and efficient way to treat atrial fibrillation. This mini review aims to highlight the mechanisms of pulsed field ablation, its history and evolution, previous studies showing its efficacy, its major challenges and pitfalls, and future advancements to overcome these challenges. This method of ablation could potentially revolutionize the treatment of atrial fibrillation and prevent recurrences, thereby making it easier for the physicians and patients involved.

Catheter Ablation Approaches for the Treatment of Arrhythmia Recurrence in Patients with a Durable Pulmonary Vein Isolation

Catheter ablation has emerged as an effective treatment for atrial arrhythmias, and pulmonary vein isolation (PVI) is the cornerstone of ablation strategies. Significant technological evolution and widespread increase in operator experience have facilitated the effectiveness of catheter ablation to achieve durable PVIs in single or multiple ablation procedures. Nevertheless, arrhythmia recurrence is a common problem even after establishing PVI. Data on catheter ablation in these patients are sparse and repeat ablation in this population is highly challenging. In this review we have summarized the available data as well as potential strategies of catheter ablation following the initial PVI.

Safety and acute efficacy of catheter ablation for atrial fibrillation with pulsed field ablation vs thermal energy ablation: A meta-analysis of single proportions

Background

Pulsed field ablation (PFA) has emerged as a novel energy source for the ablation of atrial fibrillation (AF) using ultrarapid electrical pulses to induce cell death via electroporation.

Objective

The purpose of this study was to compare the safety and acute efficacy of ablation for AF with PFA vs thermal energy sources.

Methods

We performed an extensive literature search and systematic review of studies that evaluated the safety and efficacy of ablation for AF with PFA and compared them to landmark clinical trials for ablation of AF with thermal energy sources. Freeman-Tukey double arcsine transformation was used to establish variance of raw proportions followed by the inverse with the random-effects model to combine the transformed proportions and generate the pooled prevalence and 95% confidence interval (CI).

Results

We included 24 studies for a total of 5203 patients who underwent AF ablation. Among these patients, 54.6% (n = 2842) underwent PFA and 45.4% (n = 2361) underwent thermal ablation. There were significantly fewer periprocedural complications in the PFA group (2.05%; 95% CI 0.94-3.46) compared to the thermal ablation group (7.75%; 95% CI 5.40-10.47) (P = .001). When comparing AF recurrence up to 1 year, there was a statistically insignificant trend toward a lower prevalence of recurrence in the PFA group (14.24%; 95% CI 6.97-23.35) compared to the thermal ablation group (25.98%; 95% CI 15.75-37.68) (P = .132).

Conclusion

Based on the results of this meta-analysis, PFA was associated with lower rates of periprocedural complications and similar rates of acute procedural success and recurrent AF with up to 1 year of follow-up compared to ablation with thermal energy sources.

Acute lesion extension following pulmonary vein isolation with two novel single shot devices: Pulsed field ablation versus multielectrode radiofrequency balloon

INTRODUCTION

Pulsed-field ablation (PFA) and the multielectrode radiofrequency balloon (RFB) are two novel ablation technologies to perform pulmonary vein isolation (PVI). It is currently unknown whether these technologies differ in lesion formation and lesion extent. We compared the acute lesion extent after PVI induced by PFA and RFB by measuring low-voltage area in high-density maps and the release of biomolecules reflecting cardiac injury.

METHODS

PVI was performed with a pentaspline catheter (FARAPULSE) applying PFA or with the compliant multielectrode RFB (HELIOSTAR). Before and after PVI high-density mapping with CARTO 3 was performed. In addition, blood samples were taken before transseptal puncture and after post-PVI remapping and serum concentrations of high-sensitive Troponin I were quantified by immunoassay.

RESULTS

Sixty patients undergoing PVI by PFA (n = 28, age 69 ± 12 year, 60% males, 39.3% persistent atrial fibrillation [AF]) or RFB (n = 32, age 65 ± 13 year, 53% males, 21.9% persistent AF) were evaluated. Acute PVI was achieved in all patients in both groups. Mean number of PFA pulses was 34.2 ± 4.5 and mean number RFB applications was 8.5 ± 3 per patient. Total posterior ablation area was significantly larger in PFA (20.7 ± 7.7 cm²) than in RFB (7.1 ± 2.09 cm²; p < .001). Accordingly, posterior ablation area for each PV resulted in larger lesions after PFA versus RFB (LSPV 5.2 ± 2.7 vs. 1.9 ± 0.8 cm², LIPV 5.5 ± 2.3 vs. 1.9 ± 0.8 cm², RSPV 4.7 ± 1.9 vs. 1.6 ± 0.5 cm², RIPV 5.3 ± 2.1 vs. 1.6 ± 0.7 cm,² respectively; p < .001). In a subset of 38 patients, increase of hsTropI was higher after PFA (625 ± 138 pg/mL, n = 28) versus RFB (148 ± 36 pg/mL, n = 10; p = .049) supporting the evidence of larger lesion extent by PFA.

CONCLUSION

PFA delivers larger acute lesion areas and higher troponin release upon successful PVI than multielectrode RFB-based PVI in this single-center series.

Effects of Inflammatory Cell Death Caused by Catheter Ablation on Atrial Fibrillation

Atrial fibrillation (AF) poses a serious healthcare burden on society due to its high morbidity and the resulting serious complications such as thrombosis and heart failure. The principle of catheter ablation is to achieve electrical isolation by linear destruction of cardiac tissue, which makes AF a curable disease. Currently, catheter ablation does not have a high long-term success rate. The current academic consensus is that inflammation and fibrosis are central mechanisms in the progression of AF. However, artificially caused inflammatory cell death by catheter ablation may have a significant impact on structural and electrical remodeling, which may affect the long-term prognosis. This review first focused on the inflammatory response induced by apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis and their interaction with arrhythmia. Then, we compared the differences in cell death induced by radiofrequency ablation, cryoballoon ablation and pulsed-field ablation. Finally, we discussed the structural and electrical remodeling caused by inflammation and the association between inflammation and the recurrence of AF after catheter ablation. Collectively, pulsed-field ablation will be a revolutionary innovation with faster, safer, better tissue selectivity and less inflammatory response induced by apoptosis-dominated cell death.

Practical guidance to reduce radiation exposure in electrophysiology applying ultra low-dose protocols: a European Heart Rhythm Association review

Interventional electrophysiology offers a great variety of treatment options to patients suffering from symptomatic cardiac arrhythmia. Catheter ablation of supraventricular and ventricular tachycardia has globally evolved a cornerstone in modern arrhythmia management. Complex interventional electrophysiological procedures engaging multiple ablation tools have been developed over the past decades. Fluoroscopy enabled interventional electrophysiologist throughout the years to gain profound knowledge on intracardiac anatomy and catheter movement inside the cardiac cavities and hence develop specific ablation approaches. However, the application of X-ray technologies imposes serious health risks to patients and operators. To reduce the use of fluoroscopy during interventional electrophysiological procedures to the possibly lowest degree and to establish an optimal protection of patients and operators in cases of fluoroscopy is the main goal of modern radiation management. The present manuscript gives an overview of possible strategies of fluoroscopy reduction and specific radiation protection strategies.

Pulsed Field Ablation for the Treatment of Atrial Fibrillation: PULSED AF Pivotal Trial

BACKGROUND

Pulsed field ablation uses electrical pulses to cause nonthermal irreversible electroporation and induce cardiac cell death. Pulsed field ablation may have effectiveness comparable to traditional catheter ablation while preventing thermally mediated complications.

METHODS

The PULSED AF pivotal study (Pulsed Field Ablation to Irreversibly Electroporate Tissue and Treat AF) was a prospective, global, multicenter, nonrandomized, paired single-arm study in which patients with paroxysmal (n=150) or persistent (n=150) symptomatic atrial fibrillation (AF) refractory to class I or III antiarrhythmic drugs were treated with pulsed field ablation. All patients were monitored for 1 year using weekly and symptomatic transtelephonic monitoring; 3-, 6-, and 12-month ECGs; and 6- and 12-month 24-hour Holter monitoring. The primary effectiveness end point was freedom from a composite of acute procedural failure, arrhythmia recurrence, or antiarrhythmic escalation through 12 months, excluding a 3-month blanking period to allow recovery from the procedure. The primary safety end point was freedom from a composite of serious procedure- and device-related adverse events. Kaplan-Meier methods were used to evaluate the primary end points.

RESULTS

Pulsed field ablation was shown to be effective at 1 year in 66.2% (95% CI, 57.9 to 73.2) of patients with paroxysmal AF and 55.1% (95% CI, 46.7 to 62.7) of patients with persistent AF. The primary safety end point occurred in 1 patient (0.7%; 95% CI, 0.1 to 4.6) in both the paroxysmal and persistent AF cohorts.

CONCLUSIONS

PULSED AF demonstrated a low rate of primary safety adverse events (0.7%) and provided effectiveness consistent with established ablation technologies using a novel irreversible electroporation energy to treat patients with AF.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04198701.

Pulsed Field Ablation for Atrial Fibrillation

Catheter ablation is a widely used, effective and safe treatment for AF. Pulsed field ablation (PFA), as a novel energy source for cardiac ablation, has been shown to be tissue selective and is expected to decrease damage to non-cardiac tissue while providing high efficacy in pulmonary vein isolation. The FARAPULSE ablation system (Boston Scientific) follows the idea of single-shot ablation and is the first device approved for clinical use in Europe. Since its approval, multiple high-volume centres have performed increasing numbers of PFA procedures in patients with AF and have published their experiences. This review summarises the current clinical experience regarding the use of PFA for AF using the FARAPULSE system. It provides an overview of its efficacy and safety.