Pulsed Field or Conventional Thermal Ablation for Paroxysmal Atrial Fibrillation

Pulsed-field ablation for paroxysmal atrial fibrillation: An indirect comparison of effectiveness among three proprietary devices conducted in the absence of randomized trials

INTRODUCTION

In patients with paroxysmal atrial fibrillation, pulsed-field ablation has been developed as an alternative to thermal ablation. Three devices are currently available: Farawave by Boston, PulseSelect by Medtronic, and Varipulse by Johnson. In the present report, we studied the outcomes at 12 months of these three devices using indirect comparisons.

METHODS

A standard PubMed search was conducted that identified all studies evaluating these devices in patients with paroxysmal atrial fibrillation. The endpoint was freedom from arrhythmia recurrence. Kaplan-Meier curves were subjected to the IPDfromKM method that generated reconstructed patients. Standard time-to-event statistical testss (including heterogeneity assessment) were performed.

RESULTS

Our analysis included 9 studies (8 single-arm and 1 randomized trial based on Farawave for a total of 1916 patients). A significant heterogeneity was found across the trials using Farawave because the outcomes found in the single-arm trials were better than those found in the randomized trial. Farawave (according exclusively to the results of the randomized trial), PulseSelect, and Varipulse showed a similar time-course of their respective outcomes with no significant difference. The single-arm trials using Farawave showed better outcomes than the randomized trial using Farawave and the pivotal trials using PulseSelect and Varipulse.

DISCUSSION

Our study provided an updated overview of all the studies that have so far used pulsed-fileld ablation in patients with paroxysmal atrial fibrillation.

[Technical principles of ablation therapy]

Catheter ablation is a standard procedure in modern cardiology. It can significantly improve the quality of life and life expectancy of cardiac arrhythmia patients. Besides cardiac mapping, ablation itself is a fundamental step to successfully treat cardiac arrhythmias. There are various ablation technologies at hand: In traditional radiofrequency (RF) ablation, electrical current flow generates coagulation necrosis. When understanding the biophysical principles of RF ablation, the investigator is capable to adapt lesion geometry and size to the requirements of the procedure and vary them individually. In addition, lesion metric indices evaluate and integrate important parameters such as power, duration, impedance and contact force to standardize and control RF lesions. Cryoablation induces ice crystals within myocardial tissue, which lead to destruction and electrical scarring of the treated tissue. Histologically, cryolesions are well-delineated with preserved tissue architecture and intact endocardium. Pulsed field ablation (PFA) is a novel rising technology, particularly used for pulmonary vein isolation. In contrast to classic thermal technologies (RF and cryoablation), PFA uses pulsed electrical fields to electroporate cardiac tissue and thereby creates damage on a cellular level only.

Cost, Efficiency and Outcomes of Pulsed Field Ablation versus Thermal Ablation for Atrial Fibrillation: A Real World Study

BACKGROUND

With the exponential growth of catheter ablation (CA) for atrial fibrillation (AF), there is increasing interest in associated healthcare costs. Pulsed field ablation (PFA) using a single-shot pentaspline multi-electrode catheter has been shown to be safe and effective for AF CA, but its cost efficiency compared to conventional thermal ablation modalities (cryoballoon [CB] or radiofrequency [RF]) has not been evaluated.

OBJECTIVE

To compare cost, efficiency, effectiveness and safety between PFA, CB and RF for AF ablation.

METHODS

We studied 707 consecutive patients (208 PFA, 325 CB, 174 RF) undergoing first-time AF ablation. Individual procedural costs were calculated, including equipment, lab utilisation and hospital stay, and compared between ablation modalities, as effectiveness and safety.

RESULTS

Skin-to-skin times and catheter lab times were significantly shorter with PFA (68min/102min) vs CB (91min/122min) and RF (89min/123 min); p<0.001. General anaesthesia utilisation differed across modalities (PFA 100%, CB 10.2%, RF 61.5%); p<0.001. Major complications occurred in 1% of cases, with no significant differences between modalities. Shorter procedural times resulted in lower staffing and lab costs with PFA, but these savings were offset by substantially higher equipment costs, resulting in higher overall median costs with PFA (£10,010) vs CB (£8,106) and RF (£8,949); p<0.001.

CONCLUSION

In this contemporary real-world study of the three major AF CA modalities used concurrently, PFA had shorter skin-to-skin and catheter lab times than CB and RF, with similarly low rates of complications. However, PFA procedures were considerably more expensive, largely due to higher equipment cost.

Dual-energy lattice-tip ablation system for persistent atrial fibrillation: a randomized trial

Clinical outcomes of catheter ablation for atrial fibrillation (AF) are suboptimal due, in part, to challenges in achieving durable lesions. Although focal point-by-point ablation allows for the creation of any required lesion set, this strategy necessitates the generation of contiguous lesions without gaps. A large-tip catheter, capable of creating wide-footprint ablation lesions, may increase ablation effectiveness and efficiency. In a randomized, single-blind, non-inferiority trial, 420 patients with persistent AF underwent ablation using a large-tip catheter with dual pulsed field and radiofrequency energies versus ablation using a conventional radiofrequency ablation system. The primary composite effectiveness endpoint was evaluated through 1 year and included freedom from acute procedural failure and repeat ablation at any time, plus arrhythmia recurrence, drug initiation or escalation or cardioversion after a 3-month blanking period. The primary safety endpoint was freedom from a composite of serious procedure-related or device-related adverse events. The primary effectiveness endpoint was observed for 73.8% and 65.8% of patients in the investigational and control arms, respectively (P < 0.0001 for non-inferiority). Major procedural or device-related complications occurred in three patients in the investigational arm and in two patients in the control arm (P < 0.0001 for non-inferiority). In a secondary analysis, procedural times were shorter in the investigational arm as compared to the control arm (P < 0.0001). These results demonstrate non-inferior safety and effectiveness of the dual-energy catheter for the treatment of persistent AF. Future large-scale studies are needed to gather real-world evidence on the impact of the focal dual-energy lattice catheter on the broader population of patients with AF. ClinicalTrials.gov identifier: NCT05120193 .

Recurrences after Pulsed Field Ablation of Atrial Fibrillation: Incidence, Mechanisms, Predictors, and Comparison with Thermal Energy

Pulsed Field Ablation (PFA) is the latest and most intriguing technology for catheter ablation of atrial fibrillation, due to its capability to generate irreversible and cardiomyocytes-selective electroporation of cell membranes by delivering microsecond-lasting high-voltage electrical fields, leading to high expectations. The first trials to assess the clinical success of PFA, reported an arrhythmia-free survival at 1-year of 78.5%, while other trials showed less enthusiastic results: 66.2% in paroxysmal and 55.1% in persistent AF. Nevertheless, real world data are encouraging. The isolation of pulmonary veins with PFA is easily achieved with 100% acute success. Systematic invasive remapping showed a high prevalence of durable pulmonary vein isolation at 75 and 90 days (range 84-96%), which were significatively lower in redo procedures (64.3%). The advent of PFA is prompting a reconsideration of the role of the autonomic nervous system in AF ablation, as PFA-related sparing of the ganglionated plexi could lead to the still undetermined effect on late arrhythmias' recurrences. Moreover, a new concept of a blanking period could be formulated with PFA, according to its different mechanism of myocardial injury, with less inflammation and less chronic fibrosis. Finally, in this review, we also compare PFA with thermal energy.

Advances in Clinical Cardiology 2023: A Summary of Key Clinical Trials

INTRODUCTION

Over the course of 2023, numerous key clinical trials with valuable contributions to clinical cardiology were published or presented at major international conferences. This review seeks to summarise these trials and reflect on their clinical context.

METHODS

The authors collated and reviewed clinical trials presented at major cardiology conferences during 2023 including the American College of Cardiology (ACC), European Association for Percutaneous Cardiovascular Interventions (EuroPCR), European Society of Cardiology (ESC), Transcatheter Cardiovascular Therapeutics (TCT), American Heart Association (AHA), European Heart Rhythm Association (EHRA), Society for Cardiovascular Angiography and Interventions (SCAI), TVT-The Heart Summit (TVT) and Cardiovascular Research Technologies (CRT). Trials with a broad relevance to the cardiology community and those with potential to change current practice were included.

RESULTS

A total of 80 key cardiology clinical trials were identified for inclusion. Key trials in acute coronary syndrome (ACS) and antiplatelet management such as HOST-IDEA, T-PASS and STOP-DAPT3 were included in addition to several pivotal interventional trials such as ORBITA 2, MULTISTARS-AMI, ILUMIEN-IV, OCTIVUS and OCTOBER. Additionally, several trials evaluated new stent design and technology such as BIOSTEMI, PARTHENOPE and TRANSFORM. Structural intervention trials included long-term data from PARTNER 3, new data on the durability of transcatheter aortic valve intervention (TAVI), in addition to major new trials regarding transcatheter tricuspid valve intervention from TRISCEND II. Heart failure (HF) and prevention covered several key studies including DAPA-MI, STEP-HF, ADVOR, DICTATE HF and CAMEO-DAPA. In cardiac devices and electrophysiology, several trial exploring novel ablation strategies in atrial fibrillation (AF) such as PULSED AF and ADVENT were presented with further data evaluating the efficacy of anticoagulation in subclinical AF in NOAH-AFNET 6, FRAIL AF and AZALEA-TIMI 71.

CONCLUSION

This article presents a summary of key clinical cardiology trials published and presented during the past year and should be of interest to both practising clinicians and researchers.

Sex-based differences and risk of recurrence in patients with atrial fibrillation undergoing pulmonary vein isolation

INTRODUCTION

Studies suggest increased likelihood of atrial fibrillation (AF) recurrence after catheter ablation (CA) in women than in men, indicating that sex may be an independent risk factor for recurrence. Nevertheless, the influence of sex on AF recurrence and underlying mechanisms remains unclear.

METHODS

Retrospective, single-centre study including patients undergoing AF CA between 2017 and 2021. Late recurrence (LR) was defined as AF recurrence ≥90 days after ablation, whereas early recurrence (ER) occurred within 90 days.

RESULTS

656 patients (32% women) were included, with a median follow-up period of 26 months. Compared to men, women undergoing CA were older, had higher body mass indexes, and had higher rates of hypertension, thyroid dysfunction, and valvular disease. Women also had increased LR risk after CA (HR 1.76, 95% CI [1.19, 2.59]). A time-split multivariable analysis at one year of follow-up showed no difference in LR risk during the first 12 months after CA (HR 1.19, 95% CI [0.73, 1.94]); however, LR risk increased in women (HR 2.90, 95% CI [1.68, 5.01]) after 12 months. In a sex-stratified analysis, coronary calcium score (CCS) >100 was associated with increased LR risk in men (HR 1.81, 95% CI [1.06, 3.08]), but not in women. Cardiac adipose tissue volume was not associated with increased LR risk.

CONCLUSIONS

Fewer women underwent CA than men and LR was more frequent in women, particularly one year after the procedure. CCS was associated with increased LR risk in men.

AF Ablation Using a Novel "Single-Shot" Map-and-Ablate Spherical Array Pulsed Field Ablation Catheter: 1-Year Outcomes of the First-in-Human PULSE-EU Trial

BACKGROUND

During pulsed field ablation (PFA), electrode-tissue proximity optimizes lesion quality. Recently, a novel "single-shot" map-and-ablate spherical multielectrode PFA array catheter that is able to verify electrode-tissue contact was studied in a first-in-human trial of atrial fibrillation.

OBJECTIVE

To report lesion durability data, safety and 12-months effectiveness outcomes.

METHODS

The spherical PFA catheter, an all-in-one mapping and ablation system, was used to render anatomy and deliver biphasic pulses (ungated 1.7kV pulses; ∼40 sec/application). Ablation sites included pulmonary veins (PVs), and in selected patients, posterior wall (PW) and mitral isthmus (MI). Follow-up was invasive remapping at ∼3 months, ECGs, Holters at 6 and 12 months, and symptomatic and scheduled transtelephonic monitoring. The primary and secondary efficacy endpoints were acute PVI, PVI durability and atrial arrhythmia recurrence.

RESULTS

In the 48-patient AF cohort (paroxysmal-48% / persistent-52%), lesion sets included PVI (n=48; 1.2 applications/PV), PW (n=20; 3.6 applications/PW) and MI (n=11; 2.9 applications/MI). Lesions were acutely successful for all 187 of 187 PVs (100%), 20 of 20 PWs (100%) and 10 of 11 MIs (91%). Pulse delivery time, LA catheter dwell time and procedure time was 61.5±32.8 seconds, 53.9±26.5 min and 87.8±29.8 min, respectively. Remapping (43 of 48 pts; 89.5%) revealed that 158 of 169 PVs (93.5%) were durably isolated. The only complication was a drug-responsive pericarditis. The 1-year Kaplan-Meier estimates of freedom from atrial arrhythmia were 84.2% (paroxysmal AF) and 80.0% (persistent AF).

CONCLUSION

The single-shot spherical array PFA catheter can safely achieve durable lesions, translating into good clinical efficacy.

Comparing pulsed field electroporation and radiofrequency ablation for the treatment of paroxysmal atrial fibrillation: design and rationale of the BEAT PAROX-AF randomized clinical trial

AIMS

Using thermal-based energy sources [radiofrequency (RF) energy/cryo energy] for catheter ablation is considered effective and safe when performing pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). However, treatment success remains limited and complications can occur due to the propagation of thermal energy into non-target tissues. We aim to compare pulsed field ablation (PFA) with RF ablation in terms of efficacy and safety for patients with drug-resistant paroxysmal AF.

METHODS AND RESULTS

The BEAT PAROX-AF trial is a European multicentre, superiority, open-label randomized clinical trial in two parallel groups. A total of 292 participants were recruited in 9 high-volume European clinical centres in 5 countries. Patients with paroxysmal AF were randomized to PFA (FARAPULSE Endocardial Ablation System©, Boston Scientific) or RF using the CLOSE protocol with contact force sensing catheter (SmartTouch© catheter and CARTO© Biosense Webster). The primary endpoint will be the 1-year recurrence of atrial arrhythmia, and the major secondary safety endpoint will be the occurrence of acute (<7 days) procedure-related serious adverse events, or pulmonary vein stenosis, or atrio-oesophageal fistula up to 12 months. Additionally, five sub-studies investigate the effect of PFA on oesophageal safety, cerebral lesions, cardiac autonomic nervous system, durability of PVI as assessed during redo ablation procedures, and atrial and ventricular function. The study began on 27 December 2021 and concluded recruitment on 17 January 2024. Results will be available in mid-2025.

CONCLUSION

The BEAT PAROX-AF trial aims to provide critical insights into the optimal treatment approach for patients with paroxysmal AF.

Dual energy for pulmonary vein isolation using dual-energy focal ablation technology integrated with a three-dimensional mapping system: SmartfIRE 3-month results

AIMS

Contact force (CF)-sensing radiofrequency (RF) catheters with an ablation index have shown reproducible outcomes for the treatment of atrial fibrillation (AF) in large multicentre studies. A dual-energy (DE) focal CF catheter to deliver RF and unipolar/biphasic pulsed field ablation (PFA), integrated with a three-dimensional (3D) mapping system, can provide operators with additional flexibility. The SmartfIRE study assessed the safety and efficacy of this novel technology for the treatment of drug-refractory, symptomatic paroxysmal AF. Results at 3 months post-ablation are presented here.

METHODS AND RESULTS

Pulmonary vein isolation (PVI) was performed using a DE focal, irrigated CF-sensing catheter with the recommendation of PFA at posterior/inferior and RF ablation at the anterior/ridge/carina segments. Irrespective of energy, a tag size of 3 mm; an inter-tag distance ≤6 mm; a target index of 550 for anterior, roof, ridge, and carina; and a target index of 400 for posterior and inferior were recommended. Cavotricuspid isthmus ablation was permitted in patients with documented typical atrial flutter. The primary effectiveness endpoint was acute procedural success. The primary safety endpoint was the rate of primary adverse events (PAEs) within 7 days of the procedure. A prespecified patient subset underwent oesophageal endoscopy (EE; 72 h post-procedure), neurological assessment (NA; pre-procedure and discharge), and cardiac computed tomography (CT)/magnetic resonance angiogram (MRA) imaging (pre-procedure and 3 months post-procedure) for additional safety evaluation, and a mandatory remapping procedure (Day 75 ± 15) for PVI durability assessment. Of 149 patients enrolled between February and June 2023, 140 had the study catheter inserted (safety analysis set) and 137 had ablation energy delivered (per-protocol analysis set). The median (Q1/Q3) total procedure and fluoroscopy times were 108.0 (91.0/126.0) and 4.2 (2.3/7.7) min (n = 137). The acute procedural success rate was 100%. First-pass isolation was achieved in 89.1% of patients and 96.8% of veins. Cavotricuspid isthmus ablations were successfully performed in 12 patients [pulsed field (PF) only: 6, RF only: 5, and RF/PF: 1]. The PAE rate was 4.4% [6/137 patients; 2 pulmonary vein (PV) stenoses, 2 cardiac tamponades/perforations, 1 stroke, and 1 pericarditis]. No coronary artery spasm was reported. No oesophageal lesion was seen in the EE subset (0/31, 0%). In the NA subset (n = 30), microemboli lesions were identified in 2 patients (2/30, 6.7%), both of which were resolved at follow-up; only 1 was symptomatic (silent cerebral lesion, 3.3%). In the CT/MRA subset (n = 30), severe PV narrowing (of >70%) was detected in 2 patients (2/30, 6.7%; vein level 2/128, 1.6%), of whom 1 underwent dilatation and stenting and 1 was asymptomatic; both were associated with high index values and a small inter-tag distance. In the PV durability subset (n = 30), 100/115 treated PVs (87%) were durably isolated and 18/30 patients (60.0%) had all PVs durably isolated.

CONCLUSION

A DE focal CF catheter with 3D mapping integration showed a 100% acute success rate with an acceptable safety profile in the treatment of paroxysmal AF. Prespecified 3-month remapping showed notable PVI durability.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05752487.

2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

Initial clinical experience with the balloon-in-basket pulsed field ablation system: acute results of the VOLT CE mark feasibility study

AIMS

Pulsed field ablation (PFA) for the treatment of atrial fibrillation (AF) potentially offers improved safety and procedural efficiencies compared with thermal ablation. Opportunities remain to improve effective circumferential lesion delivery, safety, and workflow of first-generation PFA systems. In this study, we aim to evaluate the initial clinical experience with a balloon-in-basket, 3D integrated PFA system with a purpose-built form factor for pulmonary vein (PV) isolation.

METHODS AND RESULTS

The VOLT CE Mark Study is a pre-market, prospective, multi-centre, single-arm study to evaluate the safety and effectiveness of the Volt™ PFA system for the treatment of paroxysmal (PAF) or persistent AF (PersAF). Feasibility sub-study subjects underwent phrenic nerve evaluation, endoscopy, chest computed tomography, and cerebral magnetic resonance imaging. Study endpoints were the rate of primary serious adverse event within 7 days and acute procedural effectiveness. A total of 32 subjects (age 61.6 ± 9.6 years, 65.6% male, 84.4% PAF) were enrolled and treated in the feasibility sub-study and completed a 30-day follow-up. Acute effectiveness was achieved in 99.2% (127/128) of treated PVs (96.9% of subjects, 31/32) with 23.8 ± 4.2 PFA applications/subject. Procedure, fluoroscopy, LA dwell, and transpired ablation times were 124.6 ± 28.1, 19.8 ± 8.9, 53.0 ± 21.0, and 48.0 ± 19.9 min, respectively. Systematic assessments of initial safety revealed no phrenic nerve injury, pulmonary vein stenosis, or oesophageal lesions causally related to the PFA system and three subjects with silent cerebral lesions (9.4%). There were no primary serious adverse events.

CONCLUSION

The initial clinical use of the Volt PFA System demonstrates acute safety and effectiveness in the treatment of symptomatic, drug refractory AF.

Venous vascular closure system vs. figure-of-eight suture following atrial fibrillation ablation: the STYLE-AF Study

AIMS

Simplified ablation technologies for pulmonary vein isolation (PVI) are increasingly performed worldwide. One of the most common complications following PVI are vascular access-related complications. Lately, venous closure systems (VCSs) were introduced into clinical practice, aiming to reduce the time of bed rest, to increase the patients' comfort, and to reduce vascular access-related complications. The aim of the present study is to compare the safety and efficacy of using a VCS to achieve haemostasis following single-shot PVI to the actual standard of care [figure-of-eight suture and manual compression (MC)].

METHODS AND RESULTS

This is a prospective, multicentre, randomized, controlled, open-label trial performed at three German centres. Patients were randomized 1:1 to undergo haemostasis either by means of VCS (VCS group) or of a figure-of-eight suture and MC (F8 group). The primary efficacy endpoint was the time to ambulation, while the primary safety endpoint was the incidence of major periprocedural adverse events until hospital discharge. A total of 125 patients were randomized. The baseline characteristics were similar between the groups. The VCS group showed a shorter time to ambulation [109.0 (82.0, 160.0) vs. 269.0 (243.8, 340.5) min; P < 0.001], shorter time to haemostasis [1 (1, 2) vs. 5 (2, 10) min; P < 0.001], and shorter time to discharge eligibility [270 (270, 270) vs. 340 (300, 458) min; P < 0.001]. No major vascular access-related complication was reported in either group. A trend towards a lower incidence of minor vascular access-related complications on the day of procedure was observed in the VCS group [7 (11.1%) vs. 15 (24.2%); P = 0.063] as compared to the control group.

CONCLUSION

Following AF ablation, the use of a VCS results in a significantly shorter time to ambulation, time to haemostasis, and time to discharge eligibility. No major vascular access-related complications were identified. The use of MC and a figure-of-eight suture showed a trend towards a higher incidence of minor vascular access-related complications.

Meta-analysis of pulsed-field ablation versus cryoablation for atrial fibrillation

PURPOSE

The available data on the treatment strategy of pulsed field ablation (PFA) for patients with atrial fibrillation (AF) is limited. This study aims to provide a comparative analysis of the efficacy, safety, and procedural efficiency between PFA and cryoballoon ablation (CBA) for AF.

METHODS

We conducted a comprehensive search of the EMBASE, PubMed, Cochrane Library, and ClinicalTrials.gov databases to identify trials comparing PFA with CBA for AF from their inception until December 2023. The odds ratio (OR) and mean difference (MD), along with a 95% confidence interval (CI), were utilized as measures of treatment effect.

RESULTS

The analysis included 15 eligible trials with a total enrollment of 1880 patients. No significant differences were found in recurrent atrial arrhythmia (OR 0.83, 95% CI 0.64, 1.07) or periprocedural complications (OR 0.78, 95% CI 0.46, 1.30) between the two ablation techniques examined in this study. However, the PFA technique demonstrated a significantly shorter procedure time (MD -7.17, 95% CI -13.60, -0.73), but a longer fluoroscopy time (MD 2.53, 95% CI 0.87, 4.19). Similarly, PFA was found to be significantly associated with a decreased incidence of phrenic nerve palsy (OR 0.20, 95% CI 0.07, 0.59), but an increased incidence of cardiac tamponade (OR 4.07, 95% CI 1.15, 14.39). Moreover, there was a significantly higher release of troponin with PFA compared to CBA (MD 470.28, 95% CI 18.89, 921.67), while the increase in S100 protein and heart rate was significantly lower with PFA than with CBA (MD -64.41, 95% CI -105.46, -17.36), (MD -8.76, 95% CI -15.12, -2.40).

CONCLUSION

The utilization of PFA provides a safer, time-saving, and tissue-specific procedure compared to CBA, while maintaining comparable success rates. This has the potential to enhance procedural efficiency and optimize resource utilization in clinical practice. These findings underscore the feasibility and promise of PFA as an alternative technique for PVI in patients with AF.

Predictors of Success for Pulmonary Vein Isolation With Pulsed-field Ablation Using a Variable-loop Catheter With 3D Mapping Integration: Complete 12-month Outcomes From inspIRE

BACKGROUND

We previously presented the safety and early efficacy of the inspIRE study (Study for Treatment of Paroxysmal Atrial Fibrillation [PAF] by Pulsed-field Ablation [PFA] System With Irreversible Electroporation [IRE]). With the study's conclusion, we report the outcomes of the full pivotal study cohort, with an additional analysis of predictors of success.

METHODS

InspIRE was a prospective, multicenter, single-arm clinical trial of drug-refractory paroxysmal atrial fibrillation. Pulmonary vein isolation was performed with a variable-loop circular catheter integrated with a 3-dimensional mapping system. Follow-up with 24-hour Holter was at 3, 6, and 12 months, as well as remote rhythm monitoring: weekly from 3 to 5 months, monthly from 6 to 12 months, and for symptoms. The primary effectiveness end point (PEE) was acute pulmonary vein isolation plus freedom from any atrial arrhythmia at 12 months. Additional subanalyses report predictors of PEE success.

RESULTS

The patient cohort included 186 patients: aged 59±10 years, female 30%, and CHA2DS2-VASc 1.3±1.2. The previously reported primary adverse event rate was 0%. One serious procedure-related adverse event, urinary retention, was reported. The PEE was achieved in 75.6% (95% CI, 69.5%-81.8%). The clinical success of freedom from symptomatic recurrence was 81.7% (95% CI, 76.1%-87.2%). Simulating a monitoring method used in standard real-world practice (without protocol-driven remote rhythm monitoring), this translates to a freedom from all and symptomatic recurrence of 85.8% (95% CI, 80.8%-90.9%) or 94.0% (95% CI, 90.6%-97.5%), respectively. Multivariate analyses revealed that left ventricular ejection fraction ≥60% (adjusted odds ratio, 0.30) and patients receiving ≥48 PFA applications (adjusted odds ratio, 0.28) were independent predictors of PEE success. Moreover, PEE success was 79.2% in patients who received ≥12 PFA applications per vein compared with 57.1% in patients receiving fewer PFA applications.

CONCLUSIONS

The inspIRE study confirms the safety and effectiveness of pulmonary vein isolation using the novel 3-dimensional mapping integrated circular loop catheter. An optimal number of PFA applications (≥48 total or ≥12 per vein) resulted in an improved 1-year success rate of ≈80%.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04524364.

Real-World Data of Radiofrequency Catheter Ablation in Paroxysmal Atrial Fibrillation: Short- and Long-term Clinical Outcomes from the Prospective Multicenter REAL-AF Registry

BACKGROUND

The safety and long-term efficacy of radiofrequency (RF) catheter ablation (CA) of paroxysmal atrial fibrillation (PAF) has been well established. Contemporary techniques to optimize ablation delivery, reduce fluoroscopy use, and improve clinical outcomes have been developed.

OBJECTIVE

We aim to assess the contemporary real-world practice approach and long-term outcomes of RF-CA for PAF through a prospective multicenter registry.

METHODS

Using the REAL-AF (Real-world Experience of Catheter Ablation for the Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation; NCT04088071) registry, patients undergoing RF-CA to treat PAF across 42 high-volume institutions and 79 experienced operators were evaluated. The procedures were performed using zero or reduced fluoroscopy, contact force sensing catheters, wide area circumferential ablation, and ablation index as a guide with a target of 380-420 for posterior and 500-550 for anterior lesions. The primary efficacy outcome was freedom from all-atrial arrhythmia recurrence at 12 months.

RESULTS

A total of 2,470 patients undergoing CA of registry from January 2018 to December 2022 were included. The mean age was 65.2 ±11.14 years, and 44% were female. Most procedures were performed without fluoroscopy (71.5%), with average procedure and total RF times of 95.4±41.7 and 22.1±11.8 min, respectively. At one-year follow-up, freedom from all-atrial arrhythmias was 81.6% with 89.7% of these patients off antiarrhythmic drugs. No significant difference was identified comparing PVI vs. PVI+ ablation approaches. The complication rate was 1.9%.

CONCLUSIONS

Refinement of RF-CA to treat PAF using contemporary tools, standardized protocols, and electrophysiology laboratory workflows, resulted in excellent short and long-term clinical outcomes.

Pulmonary Vein Isolation with a Novel Size-Adjustable Cryo-Balloon Catheter: A Tailored Ablation Protocol

Background: Pulmonary vein isolation (PVI) is a common therapeutic approach for symptomatic atrial fibrillation (AF). Among various techniques, cryo-balloon (CB) PVI is widely adopted, but, to date, established CB systems have had fixed balloon sizes. A novel size-adjustable CB, allowing balloon size adjustments during ablation, lacks sufficient data on optimal utilization in patient care. This study aims to systematically investigate this feature with a tailored ablation protocol. Methods: Our single-center prospective study included patients with paroxysmal or persistent atrial fibrillation undergoing first-time PVI with the size-adjustable CB from July 2023 to February 2024. Ablation was performed using the balloon size that provided better occlusion. The ablation protocol involved an initial occlusion test with the small balloon size (28 mm). If optimal occlusion (occlusion level 4) could not be achieved, an attempt with the larger balloon (31 mm) was initiated. Ablation was conducted using the balloon configuration that provided better occlusion of the pulmonary vein ostium. Results: Our prospective study includes 50 patients (median age [interquartile range, IQR]: 72 [65; 79] years, 24 [48.0%] females, and 35 [70.0%] patients with paroxysmal AF). The median procedure duration (IQR) was 77 (65; 96) minutes, and the median fluoroscopy time (IQR) was 17.7 (12.5; 22.0) min. PVI was successfully accomplished in each treated pulmonary vein (PV), with 87.4% of PVs isolated during the first freeze. The large balloon configuration was used to isolate 16.8% of PVs. Conclusions: The utilization of the size-adjustable CB, combined with the presented tailored ablation workflow, appears to facilitate effective and efficient pulmonary vein isolation. The use of a larger balloon configuration appears beneficial in isolating a significant proportion of the PVs.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society (HRS), the Asia Pacific HRS, and the Latin American HRS.

Pulsed-field vs cryoballoon vs radiofrequency ablation: Outcomes after pulmonary vein isolation in patients with persistent atrial fibrillation

BACKGROUND

Pulsed-field ablation (PFA) has shown promising data in terms of safety and procedural efficiency for pulmonary vein isolation (PVI), with similar long-term outcomes compared to radiofrequency ablation (RFA) and cryoballoon ablation (CBA) in patients with paroxysmal atrial fibrillation (AF).

OBJECTIVE

The purpose of this study was to compare the procedural and long-term outcomes in patients with persistent AF undergoing PVI using PFA, CBA, or RFA.

METHODS

Consecutive patients with persistent AF undergoing first PVI with PFA, CBA, or RFA were included. Patients underwent 7-day Holter electrocardiography at 3, 6, and 12 months postablation. The primary outcome was recurrence of any atrial arrhythmia after a 90-day blanking period. Safety outcomes included the composite of in-hospital major adverse events.

RESULTS

A total of 533 patients with persistent AF underwent PVI using PFA (n = 214, 39%), CBA (n = 190, 36%), or RFA (n = 129, 24%). Procedures with PFA guided by fluoroscopy were shorter than those with CBA (median 60 minutes; interquartile range [IQR] 53-80 minutes vs 84 minutes; IQR 68-101 minutes; P ≤ .001), and procedures with PFA in combination with 3-dimensional electroanatomic mapping were shorter than those with RFA (median 101 minutes; IQR 85-126 minutes vs 171 minutes; IQR 141-204 minutes; P < .001). Acute safety events occurred in 2.3%, 2.6%, and 0.8% in the PFA, CBA, and RFA groups, respectively (P = .545). The 1-year confounder-adjusted estimate for freedom from atrial arrhythmias was 62.1% for CBA, 55.3% for PFA, and 48.3% for RFA (CBA vs PFA: P = .79; CBA vs RFA: P = .009; PFA vs RFA: P = .010).

CONCLUSION

In patients with persistent AF undergoing first PVI, 1-year confounder-adjusted outcomes are better with PFA and CBA than with RFA.

Pulsed field ablation versus thermal energy ablation for atrial fibrillation: a systematic review and meta-analysis of procedural efficiency, safety, and efficacy

BACKGROUND

Pulsed field ablation (PFA) induces cell death through electroporation using ultrarapid electrical pulses. We sought to compare the procedural efficiency characteristics, safety, and efficacy of ablation of atrial fibrillation (AF) using PFA compared with thermal energy ablation.

METHODS

We performed an extensive literature search and systematic review of studies that compared ablation of AF with PFA versus thermal energy sources. Risk ratio (RR) 95% confidence intervals (CI) were measured for dichotomous variables and mean difference (MD) 95% CI were measured for continuous variables, where RR < 1 and MD < 0 favor the PFA group.

RESULTS

We included 6 comparative studies for a total of 1012 patients who underwent ablation of AF: 43.6% with PFA (n = 441) and 56.4% (n = 571) with thermal energy sources. There were significantly shorter procedures times with PFA despite a protocolized 20-min dwell time (MD - 21.95, 95% CI - 33.77, - 10.14, p = 0.0003), but with significantly longer fluroscopy time (MD 5.71, 95% CI 1.13, 10.30, p = 0.01). There were no statistically significant differences in periprocedural complications (RR 1.20, 95% CI 0.59-2.44) or recurrence of atrial tachyarrhythmias (RR 0.64, 95% CI 0.31, 1.34) between the PFA and thermal ablation cohorts.

CONCLUSIONS

Based on the results of this meta-analysis, PFA was associated with shorter procedural times and longer fluoroscopy times, but no difference in periprocedural complications or rates of recurrent AF when compared to ablation with thermal energy sources. However, larger randomized control trials are needed.

One-year outcomes of pulmonary vein isolation with a novel cryoballoon: Primary results of the FROZEN AF trial

INTRODUCTION

Cryoablation therapy for pulmonary vein isolation (PVI) to treat paroxysmal atrial fibrillation (PAF) is well established. A novel 28 mm cryoballoon system designed to operate under low pressure to safely reach a lower nadir temperature and maintain constant balloon size during cooling has not been prospectively studied in a large patient population for safety and efficacy. The FROZEN AF (NCT04133168) trial was an international multicenter, open-label, prospective, single-arm study on the safety and performance of a novel cryoballoon system for treatment of PAF.

METHODS AND RESULTS

The study enrolled patients at 44 sites in 10 countries across North America, Europe, and Asia. Subjects were indicated for PVI treatment of PAF and had failed or were intolerant of one or more antiarrhythmic drugs. Procedural outcomes were defined based on the 2017 HRS consensus statement. Follow-up was performed at 7 days, 3, 6, and 12 months. Data are reported as mean ± SD or median (IQR). PVI was performed with a 28 mm cryoballoon in 325 drug refractory PAF patients. Complete PVI was achieved in 95.7% of patients. In cryoablation lesions longer than 60 s, 60.1% of PV isolations required only a single cryoballoon application. Procedure related complications included: phrenic nerve palsy [temporary 4 (1.2%), persistent 0 (0.0%)], cardiac tamponade/perforation 2 (0.6%), and air embolism 1 (0.3%). Freedom from documented atrial arrhythmia recurrence at 12 months was 79.9% (AF 82.7%, AFL 96.5%, AT 98.1%), antiarrhythmic drugs (AAD) were continued or re-initiated in 26.8% of patients after the 3-month blanking period. Additionally, an extension arm enrolled 50 pts for treatment with 28/31 mm variable size cryoballoon. A single temporary PNP occurred in this group, which resolved before discharge. Freedom from documented recurrence at 12 months in these pts was 82.0%.

CONCLUSIONS

This novel cryoballoon may facilitate PVI to treat PAF, providing more options to address the variety of anatomies present in patients with PAF. This cryoballoon system proved to be safe and effective for treatment of patients with drug refractory or drug intolerant PAF.

Ultrastructural insights from myocardial ablation lesions from microsecond pulsed field vs radiofrequency energy

BACKGROUND

Ultrastructural findings immediately after pulsed field ablation (PFA) of the myocardium have not been described.

OBJECTIVES

The purpose of this study was to elucidate ultrastructural characteristics and differences between microsecond PFA at the 1- and 4-hour timepoints after pulse delivery and to compare them to irrigated radiofrequency ablation (RFA) lesions.

METHODS

Healthy swine underwent endocardial PFA or RFA followed by necropsy. Discrete microsecond PFA and irrigated RFA lesions were created in the ventricles with a lattice tip ablation catheter. Lesions were delivered in a manner so as to allow sampling to occur 1 and 4 hours after ablation. All lesions were located at necropsy, and samples were carefully obtained from within the lesion core, lesion periphery, and adjacent healthy myocardium. Transmission electron microscopic assessment was performed after fixation using paraformaldehyde and glutaraldehyde.

RESULTS

One hour after microsecond PFA delivery, myocytes were noted to be significantly and uniformly disrupted. Clustered, misaligned, swollen mitochondria coupled with degenerating nuclei and condensed chromatin were visualized. These findings progressed over the subsequent few hours with worsening edema. Similar changes were seen with RFA but reduced in severity. However, there was prominent extravasation of red blood cells with occlusion of capillaries that was not seen in PFA. At the lesion periphery, an abrupt change in the degree of myocyte damage was observed with PFA but not RFA.

CONCLUSION

Transmission electron microscopy demonstrates evidence of widespread destruction of myocytes as early as an hour after PFA and corroborates known histologic features such as sparing of vessels and sharp lesion margins.

Acute Kidney Injury Resulting From Hemoglobinuria After Pulsed-Field Ablation in Atrial Fibrillation: Is it Preventable?

BACKGROUND

High-voltage pulses can cause hemolysis.

OBJECTIVES

The authors evaluated the occurrence of hemoglobinuria after pulsed-field ablation (PFA) and its impact on renal function in patients with atrial fibrillation (AF).

METHODS

A consecutive series of patients with AF undergoing PFA were included in this analysis. The initial patients who did not receive postablation hydration immediately after the procedure were classified as group 1 (n = 28), and the rest of the study patients who received planned fluid infusion (0.9% sodium chloride ≥2 L) after the procedure were categorized as group 2 (n = 75).

RESULTS

Of the 28 patients in group 1, 21 (75%) experienced hemoglobinuria during the 24 hours after catheter ablation. The mean postablation serum creatinine (S-Cr) was significantly higher than the baseline value in those 21 patients (1.46 ± 0.28 mg/dL vs 0.86 ± 0.24 mg/dL, P < 0.001). Of those 21 patients, 4 (19%) had S-Cr. >2.5 mg/dL (mean: 2.95 ± 0.21 mg/dL). The mean number of PF applications was significantly higher in those 4 patients than in the other 17 patients experiencing hemoglobinuria (94.63 ± 3.20 vs 46.75 ± 9.10, P < 0.001). In group 2 patients, no significant changes in S-Cr were noted. The group 2 patients received significantly higher amounts of fluid infusion after catheter ablation than did those in group 1 (2,082.50 ± 258.08 mL vs 494.01 ± 71.65 mL, P < 0.001). In multivariable analysis, both hydration (R2 = 0.63, P < 0.01) and number of PFA applications (R2 = 0.33, P < 0.01) were independent predictors of postprocedure acute kidney injury.

CONCLUSIONS

On the basis of our findings, both the number of PFA applications and postablation hydration were independent predictors of renal insult that could be prevented using planned fluid infusion immediately after the procedure.

First-in-human clinical series of a novel conformable large-lattice pulsed field ablation catheter for pulmonary vein isolation

AIMS

Pulsed field ablation (PFA) has significant advantages over conventional thermal ablation of atrial fibrillation (AF). This first-in-human, single-arm trial to treat paroxysmal AF (PAF) assessed the efficiency, safety, pulmonary vein isolation (PVI) durability and one-year clinical effectiveness of an 8 Fr, large-lattice, conformable single-shot PFA catheter together with a dedicated electroanatomical mapping system.

METHODS AND RESULTS

After rendering the PV anatomy, the PFA catheter delivered monopolar, biphasic pulse trains (5-6 s per application; ∼4 applications per PV). Three waveforms were tested: PULSE1, PULSE2, and PULSE3. Follow-up included ECGs, Holters at 6 and 12 months, and symptomatic and scheduled transtelephonic monitoring. The primary and secondary efficacy endpoints were acute PVI and post-blanking atrial arrhythmia recurrence, respectively. Invasive remapping was conducted ∼75 days post-ablation. At three centres, PVI was performed by five operators in 85 patients using PULSE1 (n = 30), PULSE2 (n = 20), and PULSE3 (n = 35). Acute PVI was achieved in 100% of PVs using 3.9 ± 1.4 PFA applications per PV. Overall procedure, transpired ablation, PFA catheter dwell and fluoroscopy times were 56.5 ± 21.6, 10.0 ± 6.0, 19.1 ± 9.3, and 5.7 ± 3.9 min, respectively. No pre-defined primary safety events occurred. Upon remapping, PVI durability was 90% and 99% on a per-vein basis for the total and PULSE3 cohort, respectively. The Kaplan-Meier estimate of one-year freedom from atrial arrhythmias was 81.8% (95% CI 70.2-89.2%) for the total, and 100% (95% CI 80.6-100%) for the PULSE3 cohort.

CONCLUSION

Pulmonary vein isolation (PVI) utilizing a conformable single-shot PFA catheter to treat PAF was efficient, safe, and effective, with durable lesions demonstrated upon remapping.

Application of a circular-shaped pulsed field ablation catheter with magnetic sensors for pulmonary vein isolation: a multi-centre clinical study report

AIMS

A few studies have reported the effect and safety of pulsed field ablation (PFA) catheters for ablating atrial fibrillation (AF), which were mainly based on basket-shaped or flower-shaped designs. However, the clinical application of a circular-shaped multi-electrode catheter with magnetic sensors is very limited. To study the efficacy and safety of a PFA system in patients with paroxysmal AF using a circular-shaped multi-electrode catheter equipped with magnetic sensors for pulmonary vein isolation (PVI).

METHODS AND RESULTS

A novel proprietary bipolar PFA system was used for PVI, which utilized a circular-shaped multi-electrode catheter with magnetic sensors and allowed for three-dimensional model reconstruction, mapping, and ablation in one map. To evaluate the efficacy, efficiency, and safety of this PFA system, a prospective, multi-centre, single-armed, pre-market clinical study was performed. From July 2021 to December 2022, 151 patients with paroxysmal AF were included and underwent PVI. The study examined procedure time, immediate success rate, procedural success rate at 12 months, and relevant complications. In all 151 patients, all the pulmonary veins were acutely isolated using the studied system. Pulsed field ablation delivery was 78.4 ± 41.8 times and 31.3 ± 16.7 ms per patient. Skin-to-skin procedure time was 74.2 ± 29.8 min, and fluoroscopy time was 13.1 ± 7.6 min. The initial 11 (7.2%) cases underwent procedures with deep sedation anaesthesia, and the following cases underwent local anaesthesia. In the initial 11 cases, 4 cases (36.4%) presented transient vagal responses, and the rest were all successfully preventatively treated with atropine injection and rapid fluid infusion. No severe complications were found during or after the procedure. During follow-up, 3 cases experienced atrial flutter, and 11 cases had AF recurrence. The estimated 12-month Kaplan-Meier of freedom from arrhythmia was 88.4%.

CONCLUSION

The PFA system, comprised of a circular PFA catheter with magnetic sensors, could rapidly achieve PVI under three-dimensional guidance and demonstrated excellent safety with comparable effects.

Contemporary catheter ablation of complex atrial tachycardias after prior atrial fibrillation ablation: pulsed field vs. radiofrequency current energy ablation guided by high-density mapping

AIMS

Catheter ablation (CA) of post-ablation left atrial tachycardias (LATs) can be challenging. So far, pulsed field ablation (PFA) has not been compared to standard point-by-point radiofrequency current (RFC) energy for LAT ablation. To compare efficacy of PFA vs. RFC in patients undergoing CA for LAT.

METHODS AND RESULTS

Consecutive patients undergoing LAT-CA were prospectively enrolled (09/2021-02/2023). After electro-anatomical high-density mapping, ablation with either a pentaspline PFA catheter or RFC was performed. Patients were matched 1:1. Ablation was performed at the assumed critical isthmus site with additional ablation, if necessary. Right atrial tachycardia (RAT) was ablated with RFC. Acute and chronic success were assessed. Fifty-six patients (n = 28 each group, age 70 ± 9 years, 75% male) were enrolled.A total of 77 AT (n = 67 LAT, n = 10 RAT; 77% macroreentries) occurred with n = 32 LAT in the PFA group and n = 35 LAT in the RFC group. Of all LAT, 94% (PFA group) vs. 91% (RFC group) successfully terminated to sinus rhythm or another AT during ablation (P = 1.0). Procedure times were shorter (PFA: 121 ± 41 vs. RFC: 190 ± 44 min, P < 0.0001) and fluoroscopy times longer in the PFA group (PFA: 15 ± 9 vs. RFC: 11 ± 6 min, P = 0.04). There were no major complications. After one-year follow-up, estimated arrhythmia free survival was 63% (PFA group) and 87% (RFC group), [hazard ratio 2.91 (95% CI: 1.11-7.65), P = 0.0473].

CONCLUSION

Pulsed field ablation of post-ablation LAT using a pentaspline catheter is feasible, safe, and faster but less effective compared to standard RFC ablation after one year of follow-up. Future catheter designs and optimization of the electrical field may further improve practicability and efficacy of PFA for LAT.

Longer and better lives for patients with atrial fibrillation: the 9th AFNET/EHRA consensus conference

AIMS

Recent trial data demonstrate beneficial effects of active rhythm management in patients with atrial fibrillation (AF) and support the concept that a low arrhythmia burden is associated with a low risk of AF-related complications. The aim of this document is to summarize the key outcomes of the 9th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA).

METHODS AND RESULTS

Eighty-three international experts met in Münster for 2 days in September 2023. Key findings are as follows: (i) Active rhythm management should be part of the default initial treatment for all suitable patients with AF. (ii) Patients with device-detected AF have a low burden of AF and a low risk of stroke. Anticoagulation prevents some strokes and also increases major but non-lethal bleeding. (iii) More research is needed to improve stroke risk prediction in patients with AF, especially in those with a low AF burden. Biomolecules, genetics, and imaging can support this. (iv) The presence of AF should trigger systematic workup and comprehensive treatment of concomitant cardiovascular conditions. (v) Machine learning algorithms have been used to improve detection or likely development of AF. Cooperation between clinicians and data scientists is needed to leverage the potential of data science applications for patients with AF.

CONCLUSIONS

Patients with AF and a low arrhythmia burden have a lower risk of stroke and other cardiovascular events than those with a high arrhythmia burden. Combining active rhythm control, anticoagulation, rate control, and therapy of concomitant cardiovascular conditions can improve the lives of patients with AF.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

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.

[Development of catheter ablation of supraventricular tachycardias with special consideration of contributions from German engineers and electrophysiologists]

The development and clinical implementation of catheter ablation of supraventricular tachycardia is one of the outstanding achievements of modern cardiovascular treatment. Over a period of less than 40 years, a curative and safe treatment strategy for almost all forms of atrial arrhythmias has been developed and implemented. German electrophysiologists and engineers have made a significant contribution to this truly outstanding success story in modern medicine. Their contributions should be appropriately acknowledged because without them, the development of ablation technology and its worldwide dissemination would not have been possible. Both the technological contributions and the medical-electrophysiological contributions were at the absolute forefront of worldwide developments and have made a significant contribution to the fact that today more than 500,000 patients with symptomatic and/or threatening cardiac arrhythmias can be successfully treated every year by use of catheter ablation. We would like to thank them all for their achievements.

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.

Comparative Safety of Pulsed Field Ablation and Cryoballoon Ablation Technologies for Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation: A Critical Literature Review and Indirect Treatment Comparison

INTRODUCTION

Cryoballoon ablation (CBA) is a standard catheter ablation technology with demonstrated clinical effectiveness for the treatment of paroxysmal atrial fibrillation (PAF); however, it can be associated with major adverse events, including phrenic nerve paralysis. Pulsed field ablation (PFA) is a novel, minimally thermal technology with comparable effectiveness and low safety risk. This study aimed to compare the safety profiles of PFA and CBA through critical analyses of the literature and indirect treatment comparisons.

METHODS

Studies were identified by searching the MEDLINE database and the Clinicaltrials.gov registry. Registered clinical trials and/or Food and Drug Administration Investigation Device Exemption (FDA IDE) studies evaluating PFA or CBA in adult patients with drug-refractory PAF between January 2008 and March 2023 were selected. Comparative safety between PFA and CBA was assessed for major and prespecified adverse events. Indirect comparisons were conducted using the proportion of patients experiencing adverse events and confirmed with single-arm meta-analyses and sensitivity analyses.

RESULTS

Data were extracted from three PFA publications including a total of 497 patients and six CBA studies including a total of 1113 patients. The analysis revealed that PFA was associated with significantly lower risk of major adverse events {risk difference - 4.3% [95% confidence interval (CI) - 5.8, - 2.8]; risk ratio 0.16 [95% CI 0.07, 0.45]} and prespecified adverse events [risk difference - 2.5% (95% CI - 4.4, - 0.5); risk ratio 0.53 (95% CI 0.31, 0.96)]. Meta-analyses confirmed the lower rate of major adverse events for PFA [0.4% (95% CI 0.0, 1.3)] vs. CBA [5.6% (95% CI 2.6, 8.6)] and prespecified adverse events for PFA [2.7% (95% CI 1.2, 4.1)] vs. CBA [5.8% (95% CI 2.7, 9.0)]. Sensitivity analyses exploring heterogeneity across studies confirmed robustness of the main analyses.

CONCLUSION

The findings of this study show that PFA has a more favorable safety profile than CBA, with significantly lower risks of major and prespecified adverse events. These indirect comparisons help contextualize the safety of PFA compared to CBA for the treatment of drug-refractory PAF in the absence of head-to-head studies.

[Precision medicine enhances personalized medicine in cardiology]

Personalized medicine and precision medicine, frequently used synonymously, shall be clearly differentiated. Accordingly, personalization in cardiac medicine is based on the clinical presentation of a patient, as well as his/her cardiovascular risk factors and comorbidities, electrocardiography, imaging, and biomarkers for myocardial load and ischemia. Personalization is based on large clinical trials with detailed subgroup analyses and is practiced on the basis of guidelines. Further in depth personalization is achieved by precision medicine, which is based on innovative imaging for myocardial structure, coronary morphology, and electrophysiology. From the clinical perspective, genome analyses are relevant for comparatively rare monogenetic cardiovascular diseases. While these as well as transcriptome and metabolome analyses play a significant role in cardiovascular research with great translation potential, they have not yet been broadly introduced in the diagnosis, prevention, and treatment of complex cardiovascular diseases. Furthermore, digital technologies have considerable potential in cardiovascular precision medicine. On the one hand, this is based on the frequency of the diseases with the availability of Big Data and, on the other hand, on the availability of bio-signals and sensors of those signals in cardiovascular diseases.

Atrial Fibrillation Catheter Ablation among Cancer Patients: Utilization Trends and In-Hospital Outcomes

Background: Atrial fibrillation (AF) catheter ablation in cancer patients has been evaluated in very few studies. We aimed to investigate utilization trends and in-hospital outcomes of AF catheter ablation among cancer patients in a large US inpatient registry. Methods: Utilizing the National Inpatient Sample (NIS) database, patients who underwent AF catheter ablation between 2012 and 2019 were identified. Sociodemographic, clinical data, in-hospital procedures and outcomes were collected. Baseline characteristics and in-hospital outcomes were compared between patients with and without cancer. Results: An estimated total of 67,915 patients underwent AF catheter ablation between 2012 and 2019 in the US. Of them, 950 (1.4%) had a cancer diagnosis. Patients with a cancer diagnosis were older and had higher Charlson Comorbidity Index, CHA2DS2-VASc and ATRIA bleeding indices scores. A higher rate of total complications was observed in cancer patients (10.5% vs. 7.9, p < 0.001), driven mainly by more bleeding and infectious complications. However, no significant differences in cardiac or neurological complications as well as in-hospital mortality rates were observed and were relatively low in both groups. Conclusions: AF catheter ablation in cancer patients is associated with higher bleeding and infectious complication rates, but not with increased cardiac complications or in-hospital mortality in a US nationwide, all-comer registry.