Additional left atrial posterior wall ablation using pulsed field ablation as a safe and feasible treatment option for persistent atrial fibrillation patients

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): University Hospital Center Split

Background

Catheter ablation in persistent (PeAF), and especially long-standing persistent AF (ls-PeAF) patients often requires ablation beyond pulmonary vein isolation (PVI) (1). Adjunctive ablation of the left atrial posterior wall (LAPW) may improve outcomes of PeAF patients but has been limited by the difficulty of achieving lesion durability and concerns of thermal damage of nearby structures. Pulsed field ablation (PFA) is a new, nonthermal ablative modality, with proven myocardial ablative efficacy, quick energy delivery, and a favorable safety profile, which makes PFA suitable for the LAPW ablation (2).

Purpose

We aimed to report the safety profile, intraprocedural parameters, and acute success rate of LAPW ablation in a regular clinical setting with the CE-marked PFA platform.

Methods

This was a prospective observational study on the safety and feasibility aspects of LAPW ablation with the PFA in PeAF and ls-PeAF patients. The safety endpoints included the percentage of clinically relevant complications, including stroke/TIA, atrioesophageal fistula, cardiac tamponade, myocardial infarction, diaphragmatic paralysis, and death in the first 30-days post-procedure. Acute ablation success was confirmed with electroanatomical mapping (EAM).

Ablation was performed using 2.0 kV biphasic waveforms, 2 deliveries for each application site. The lesion set depended on the patient’s AF ablation history, LA size, and anatomy. After LA mapping and PVI or PVI touch-up (index or re-do procedure), 2 anchor lesions per vein extending to the LAPW were deployed. A lesion set was then performed between the anchor lesions on the LAPW (upper and lower row) with the catheter in a flower configuration and the intention of 75% overlap for the neighbouring application sites at 3D EAM.

Results

Twenty-three patients (87% men) received PFA LAPW ablation. The age median was 64 (Q1-Q3: 56.5-71) years. 52% had ls-PeAF and 65% had previous ablation. The median LA diameter was 47 mm (Q1-Q3: 46-52 mm). The safety endpoints did not occur in any of the patients. The LA ablation catheter dwell time median for the index and re-do procedure was 39.5 (Q1-Q3: 31-42.25) and 18 (Q1-Q3: 16-21) minutes. The median time for LAPW ablation was 10 (Q1-Q3: 8-12) minutes. The median number of application sites on the upper and lower posterior wall was 6 (Q1-Q3: 5-7) and 6 (Q1-Q3: 5-7), respectively. Acute ablation success was 100% in terms of completed box lesion, and LAPW electrical activity loss. In a single case, first-pass ablation was not achieved, but additional delivery under intracardiac echocardiography guidance resulted in the electrical silence of the targeted segment.

Conclusion

LAPW ablation with PFA is safe, quick and results in excellent acute isolation rates in PeAF patients. Posterior wall ablation with PFA is not a time-consuming procedure which is an important aspect for real-world PeAF and ls-PeAF patients who are often fragile.

Current practices and expectations to reduce Electrophysiology catheters environmental impact: a large EHRA/LIRYC European survey

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Boston Scientific

Background

Despite aiming at improving patients’ health, healthcare consumes a large amount of resources and contributes to 4.6% of the global GHG/carbon emissions, 71% of the footprint being due the supply chain. It also produces millions of tons of complex waste per year. Yet, sustainability in EP remains a complex challenge as the performance and safety for patients are critical.

Objective

To set the ground to reduce electrophysiology (EP) catheters’ environmental impact.

Methods

A survey was conducted to poll European EP centers on 24 questions on sustainability practices and expectations.

Results

278, mostly EP doctors (84%, 76% male, 43yo), working in a public environment (89%, >100 procedures/year in 53% and > 500 in 36%) participated. A majority of EP doctors uses 2 to 4 more catheters/sheath per paroxysmal AF ablation procedure. MAPPING/ABLATION catheters are discarded after the procedure (73&78%), with partial re-cycling (electrodes) in 23&26 %. Local/external sterilization is rarely used (12% & 9%).

Catheters’ packaging are discarded in medical or general waste (38 & 31%) while it is recycled in only 19%.

EP Healthcare professionals are highly motivated in being environment friendly in their personal (82%) and in EP practice (62%). They identify a lack of interest from their hospital in 59% (only 16% having an executive in charge). Other barriers are the complexity of sustainability processes (48%), the effort required to change practice (47%), infectious risk (41%), lack of training (37%) and cost (33%). EP Healthcare professionals would favor sustainable mapping /ablation catheters if performances were preserved (60 & 50%). They consider re-use as the most relevant solution (60%) while being currently illegal in some European countries. Packaging should be reduced in size or made reusable. Finally, they consider that regulatory (31%), education (19%) and recommendations by companies (19%) would encourage the field to transition to more environmentally friendly practices. Interestingly, age, gender, type of practice, country or experience did not impact the results.

Conclusion

EP Healthcare professionals demonstrate a willingness to adopt sustainable practices. They consider re-use as the most relevant approach as of today. 60/50 % would favour sustainable mapping/ablation catheters providing preserved performances. Leaping to the next level of sustainability will request development of new sustainable solutions, models and technologies. Reaching this urgent goal will require governments, industry, hospitals and doctors to work closely in a coordinated approach.

Biophysical parameters and time to isolation of pulmonary veins with a novel cryoballoon: results of POLAR ICE study

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Boston Scientific

Introduction

Low nadir temperatures and long thaw times with cryoballoon ablation are associated with successful pulmonary vein isolation (PVI). Recently, a system that maintains uniform pressure and size has been introduced to improve catheter stability during cryoballoon ablation. The present results examine the relationship between cryoballoon time to isolation (TTI) and other biophysical parameters; time to -40ºC (TT-40), nadir temperature, time to thaw (TT0), and first pass isolation success in patients with paroxysmal AF (PAF).

Methods

POLAR ICE, a prospective, non-randomized, multicenter (international) registry (NCT04250714), enrolled 400 patients across 19 centers, between Aug 2020 and May 2021. This study included any patients indicated for treatment of PAF with the POLARx cryoablation system. Cryodosing regimen was left to the operator and not specified by study protocol. Procedural characteristics, such as time to isolation (TTI), cryoablations per pulmonary vein, nadir temperature, and occlusion grade were recorded. PVI was confirmed via entrance block. Biophysical parameters for ablations longer than 120s were evaluated.

Results

Data on 389 PVI procedures (n=2303 ablations) were collected. Of those ablations, 1914 (83%) had a duration of at least 120s and were included in this analysis. Isolation was attempted using the CB alone. TTI was reported in 1335 ablations with the majority (64%) occurring within 60s. Biophysical parameters and single shot success rates were examined based on TTI. Ablations with TTI<60s had significantly faster TT-40 (30.6±7.4s), lower nadir temperatures (-58.3±5.8ºC), longer thaw times (21.1±6.7s), and a greater proportion of grade 4 occlusions (88%) than longer TTIs or ablation with no TTI reported (Table 1). In TTIs<60s single shot success was 95%, significantly greater than TT≥60s, or No TTI. Procedure-related complications included: phrenic nerve palsy (0.5%), tamponade (0.5%), AV block (0.3%), stroke (0.3%), and transient ischemic attack (0.3%).

Conclusions

These data suggest a correlation between cryoballoon biophysical parameters and single shot success. Good occlusion likely drives faster freeze and lower nadir temperatures, resulting in longer thaw times with this novel cryoballoon. Future research should examine the relationship between these parameters to drive optimization of cryoablation techniques and provide guidance toward improved workflow.

Pulsed field ablation as the first choice regarding oesophageal safety for atrial fibrillation ablation?

Funding Acknowledgements

Type of funding sources: None.

Background

The occurrence of endoscopy-detected oesophageal lesions has been reported in patients with atrial fibrillation (AF) after thermal-based pulmonary vein isolation (PVI) with even higher risk in patients undergoing ablation of the left atrial posterior wall (LAPW) (1). The main mechanism of oesophageal injury is thermal, resulting in oesophageal dysmotility, ulceration, perforation, or left atrio-oesophageal fistula formation, which are rare but life-threatening sequelae. Pulsed-field ablation (PFA) is a non-thermal ablation technology that uses high amplitude pulsed electrical fields to ablate tissues through cell membrane disruption (2). Precommercial experience with PFA reported no injury to the oesophagus for both PVI and LAPW ablation (3).

Purpose

To assess oesophageal safety in AF patients treated with three different PFA platforms.

Methods

In this single-centre experience we retrospectively analysed a total of 72 upper gastrointestinal (GI) endoscopies performed by a certified gastroenterologist one day after left atrial PFA. GI analysis focused on detection of oesophageal lesions nearest the left atrium and evidence of gastric hypomotility. PVI was performed using focal or single shot PFA catheters. Focal PFA catheters achieved PVI using the wide antral circumferential ablation (WACA) technique. LAPW ablation was performed exclusively by using single shot PFA devices.

Results

The patient characteristics were summarized in Table 1. Focal PFA catheters were used in 78% of patients. Post-procedure endoscopies revealed no mucosal lesions in any patient. Gastroparesis and perioesophageal vagal nerve injury were not found (Table 2).

Conclusion

PFA, whether applied by single shot devices or focal catheters, seems to be a safe ablation option with respect to oesophageal injury resulting from PVI and LAPW ablation in paroxysmal and persistent AF patients. Irrespective of catheter design, PFA configuration (monopolar versus bipolar, maximum output), or LA lesion set, we found absolute GI safety of PFA as class effect.

Acute procedural characteristics, efficacy, and safety of a novel cryoballoon for the treatment of paroxysmal atrial fibrillation: Results from the POLAR-ICE study

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Boston Scientific

Background/Introduction

Pulmonary vein isolation (PVI) using a cryoballoon is well-established for the treatment of paroxysmal atrial fibrillation (PAF). Initial experience with a novel cryoballoon (CB) with a stable low balloon pressure (POLARx, Boston Scientific) has demonstrated acute procedural safety and efficacy in de novo PVI procedures in patients with paroxysmal AF. However, to date, there is limited multicenter data on real world acute outcomes and procedural characteristics with this novel cryoballoon.

Purpose

The purpose of POLAR ICE was to provide real-world data on the acute and chronic outcomes of cryoballoon ablation with POLARx for the treatment of PAF. Here we report on the initial acute outcomes up to 3 months including procedural efficacy, safety, and biophysical parameters.

Methods

POLAR ICE, a prospective, non-randomized, multicenter (international) registry (NCT04250714), enrolled 400 patients across 19 centers, between Aug 2020 and May 2021. This study included any patients indicated for treatment of PAF with the POLARx cryoablation system. The study protocol did not mandate any specific cryodosing regimen, this was left to the operator. Procedural characteristics, such as time to isolation (TTI), cryoablations per pulmonary vein, balloon nadir temperature, and occlusion grade were recorded. PVI was confirmed with entrance block testing.

Results

Complete PVI was achieved in 96.1% of PVs (1437/1496). Procedure and fluoroscopy times were 69.0±25.2 min and 15.8±10.0 min, respectively. Left atrial dwell time was 47.3±18.8 min. The cryoablation characteristics by vein are shown in the Table 1. An average of 4.9±1.8 ablations were performed per patient (1.3±0.7 per vein). Grade 3 or 4 occlusion was achieved in 98.1% of PVs reported. Electrical isolation was achieved with an average TTI of 50±33.8s and in 81.4% of PVs isolation required only a single cryoablation. Nadir temperatures across all pulmonary veins averaged -56.3± 6.5C. Time to -40C was 32.9±11s and Time to Thaw (0C) was 19.5±6.7s across all veins. PVI was performed on atypical anatomies (12 LCPV, 7 RMPV, & 3 RCPV) in 19 pts. Serious adverse events included phrenic nerve palsy (0.5%), tamponade (0.5%), AV block (0.3%), stroke (0.3%), and transient ischemic attack (0.3%).

Conclusions

Real world usage data on the novel CB suggests that this device is safe and effective, with a PV isolation success rate of 96.2% and 81.4% of PVs isolated with a single cryoablation. These data are in keeping with reports on other cryoballon systems and have markedly shorter procedure times than have been previously reported on this cryoballon.

Acute safety and performance outcomes from the inspIRE trial using a novel pulsed field ablation system for the treatment of paroxysmal atrial fibrillation

Background/Introduction

The inspIRE clinical trial was designed to assess the safety and efficacy of a fully integrated biphasic pulsed field ablation (PFA) system comprised of a multi-channel generator, variable decapolar irrigated loop circular catheter, and mapping system (Figure A) for the treatment of paroxysmal atrial fibrillation (PAF).

Purpose

Using this novel PFA system in a multicentre clinical trial, we present the initial feasibility of electrical pulmonary vein isolation (PVI), procedural performance, and acute safety results.

Methods

inspIRE is a prospective, non-randomized, multi-centre study, planned to enrol up to 550 patients. PVI is performed with the novel, variable loop circular catheter, compatible mapping system and generator. Acute procedural effectiveness (entrance block in all clinically targeted PVs post adenosine/isoproterenol challenge) and the incidence of primary adverse events (PAEs) were assessed. PAEs are defined as the occurrence of cardiac tamponade/perforation, myocardial infarction, stroke/cerebrovascular accident, thromboembolism, transient ischemic attack, permanent phrenic nerve paralysis, pulmonary edema, pericarditis, and any major vascular access complications within 7 days of the ablation procedure. Additionally, any incidence of procedure or device related death, atrio-esophageal fistula, or PV stenosis (related to the ablation procedure or study catheter) within the 12M follow-up period is classified as a PAE.

Results

A total of 35 PAF subjects (age 59.7±10.7 years, 54.3% male) were treated across 5 European sites by 6 operators. Acute procedural success was achieved in 100% of study subjects (Figure B) with zero incidence of PAEs. Mean total procedure time was 82.9±19.9 minutes with 27.0±11.9 minutes of PFA from first to last application. Average fluoroscopy use was 10.6±6.8 minutes and LA dwell time was 45.6±15.3 minutes.

Conclusion

Initial results of the inspIRE trial demonstrate the acute safety and effectiveness of the new integrated IRE circular catheter, mapping system and generator for PVI in PAF patients.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): inspIRE is a company-sponsored study funded by Biosense Webster, Inc. Figure 1. (A) PFA System; (B) PVI Voltage Map

Novel cryoballoon to isolate pulmonary veins in patients with paroxysmal atrial fibrillation: one-year outcomes in a multicenter study

Background

Recently, a novel cryoballoon (CB; POLARx) has been developed with increased steerability which maintains size and pressure throughout the ablation. Initial clinical data has demonstrated acute procedural safety and efficacy in de novo pulmonary vein isolation (PVI) procedures in patients with paroxysmal atrial fibrillation (AF). However, there are limited studies demonstrating the long-term efficacy of the CB.

Purpose

To evaluate the long-term safety and efficacy of the novel CB in treating paroxysmal AF.

Methods

This was a non-randomized, prospective, multi-center study. Fifty-eight consecutive patients with paroxysmal AF were enrolled at 4 centers for de novo PVI procedures. Cryoablation was delivered for 180s if time to isolation was ≤60s. Otherwise a 240s cryoablation was performed. PVI was confirmed with entrance and exit block testing. Patients were followed for 1 year with 24-hour Holter monitoring at 3, 6, and 12 months. After a 3-month blanking period, recurrence was defined as having any documented, symptomatic episode(s) of AF or atrial tachycardia.

Results

Acute isolation with the CB was achieved in 230 of 231 pulmonary veins (99.6%) with 5.2±1.5 cryoapplications per patient (1.3±0.6 cryoapplications per vein). There were 4 patients (6.9%) with phrenic nerve injury (3 resolved during the index procedure; 1 resolved at 6 months follow-up). One serious adverse device event was reported: femoral arterial embolism event occurring 2 weeks post index procedure (1.7%). Of the 56 patients that had complete 12-month follow-up, 43 (76.8%) were free from recurrent atrial arrhythmias.

Conclusion

Initial multicenter clinical experience with the novel CB has demonstrated long-term safety and efficacy of PVI in patients with paroxysmal AF. Further studies are underway to confirm these findings.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boston Scientific