Pulsed Field Ablation Versus Radiofrequency Ablation: Esophageal Injury in a Novel Porcine Model

12-month outcomes of pulsed-field ablation with a variable-diameter circular catheter for paroxysmal atrial fibrillation: Insights into conscious sedation and fluoroscopy use

BACKGROUND

Pulsed-field ablation (PFA) emerges as an innovative nonthermal energy modality for catheter ablation of atrial fibrillation (AF). This study aimed to assess the safety and effectiveness of a novel PFA system that uses a multichannel, circular ablation catheter with adjustable diameters in treating paroxysmal AF.

METHODS

This clinical trial (PF-Beat-AF) was a prospective, multicenter, single-arm study. Patients with paroxysmal AF underwent pulmonary vein isolation (PVI) using the PFA system, and were followed at discharge, 7-day, 1-, 3-, 6- and 12-month post-procedure. Primary safety endpoint was the incidence of primary adverse events (PAEs). While primary effectiveness endpoint was freedom from documented atrial arrhythmia recurrence lasting >30 s during the 3-12 months evaluation period.

RESULTS

A total of 161 patients were enrolled and 159 patients were treated in eight centers. Conscious sedation was used in 68.6 % of cases, and 40.9 % of procedures were completed without fluoroscopy. The mean total procedure time was 132.3 ± 40.4 min, and fluoroscopy time averaged 6.4 ± 6.8 min. Acute PVI was achieved in 100 % of patients. One PAE (0.6 %) occurred (pericardial tamponade, resolved). At 12 months, 87.7 % (95 % CI: 82.5 %-92.9 %) of patients remained free from atrial arrhythmia after the blanking period. No significant differences in effectiveness were observed between conscious sedation and general anesthesia/deep sedation, or fluoroscopy and zero-fluoroscopy cases.

CONCLUSION

The results of clinical trial demonstrated the safety and effectiveness of the PFA system in treating paroxysmal AF, including successful use with conscious sedation and zero-fluoroscopy.

Pulsed Field Ablation for Persistent Atrial Fibrillation: 1-Year Results of ADVANTAGE AF

BACKGROUND

Pulsed field ablation (PFA) has gained prominence for pulmonary vein isolation (PVI) to treat atrial fibrillation, but there are limited outcome data on PFA to treat persistent atrial fibrillation (PerAF).

OBJECTIVES

This study sought to determine the safety and efficacy of PVI + posterior wall ablation (PWA) with PFA in PerAF.

METHODS

ADVANTAGE AF (A Prospective Single Arm Open Label Study of the FARAPULSE Pulsed Field Ablation System in Subjects with Persistent Atrial Fibrillation) is a prospective, single-arm, multicenter pivotal investigational device exemption study of PerAF patients undergoing PVI+PWA with the pentaspline PFA catheter. One-year follow-up included 24-hour Holter monitoring at 6 and 12 months and twice monthly and symptomatic transtelephonic monitoring. The primary safety endpoint was incidence of predefined adverse events. The primary effectiveness endpoint included acute success and postblanking 1-year freedom from atrial tachyarrhythmia recurrence (>30 seconds), redo ablation, cardioversion, or antiarrhythmic drug escalation. Endpoint analysis used Kaplan-Meier methodology with 97.5% 1-sided confidence limits compared with a 12% safety and 40% effectiveness goals, with 85% power.

RESULTS

PFA in 339 patients (260 treatment and 79 roll-in) resulted in 99.7% success for both PVI and PWA. The primary safety endpoint was 2.3% (5.1% upper confidence limit), including 1 with pericarditis, 1 with myocardial infarction, and 4 with pulmonary edema; no tamponade, stroke, pulmonary vein stenosis, or esophageal fistula occurred. Primary effectiveness was 63.5% (57.3% lower confidence limit) at 1 year, with 8.5% patients having a single, isolated atrial fibrillation recurrence. Freedom from symptomatic atrial fibrillation was 85.3%; efficacy varied by operator experience.

CONCLUSIONS

ADVANTAGE AF, the first large prospective study of PFA to treat PerAF using a strategy of PVI and posterior wall isolation, revealed favorable safety and effectiveness outcomes. (A Prospective Single Arm Open Label Study of the FARAPULSE Pulsed Field Ablation System in Subjects with Persistent Atrial Fibrillation [ADVANTAGE AF]; NCT05443594).

Acute outcomes and learning curve from the initial patients treated with the PulseSelect system: a real-world multicenter experience of pulsed field ablation

INTRODUCTION

Catheter ablation is a cornerstone in managing patients with symptomatic, drug-refractory atrial fibrillation (AF), and while effective, traditional thermal ablation techniques are associated with rare but significant complications due to a non-selective thermal energy transfer to all biologic tissues. Pulsed field ablation (PFA) offers a non-thermal approach, targeting myocardial tissue selectively while sparing adjacent structures. The PulseSelect system is a novel PFA platform, and this analysis examines the procedural outcomes, acute complications, and the learning curve associated with introduction of the PulseSelect system in six European centers.

METHODS

The One Shot to Pulmonary Vein Isolation (1STOP) project prospectively included 131 patients with paroxysmal or persistent AF treated with the PulseSelect system across six centers. Procedural data, patient characteristics, and acute outcomes were summarized. Additionally, sedation protocols, fluoroscopic times, and acute success rates were reported.

RESULTS

Patients (mean age 61.7 ± 9.7 years; 31.3% female) had predominantly paroxysmal AF (80.9%). Median procedural and fluoroscopy times were 55.0 and 16.0 min, respectively. General anesthesia was used in 75.5% of cases, while in the remaining 24.5% moderate sedation protocols allowed procedures (even in 15.1% without an anesthesiologist). Acute PVI success was 100%, and no major complications were observed. A short learning curve was noted, with significant reductions in procedural times after the initial 2-3 cases at each center.

CONCLUSION

The PulseSelect system showed short procedural times, with a rapid learning curve, thus leading with high procedural efficiency. In 1 out of 4 cases general anesthesia was not applied, and no major complications were observed.

Microsecond pulsed electric fields induce myocardial ablation by secondary mitochondrial damage and cell death mechanisms

Microsecond pulsed electric field (µsPEF) is a newer treatment modality to replace catheter ablation treatment of Atrial fibrillation (AF) due to its fewer side effects. This study aims to find out experimental parameters that effectively induce cardiomyocyte death and the precise mechanisms for microsecond pulsed electric fields (µsPEFs) ablation of cardiomyocytes. CCK8 and flow apoptosis analysis were employed to examine the effects of different µsPEFs on cardiomyocytes in vitro. The mechanisms by which the µsPEFs ablation works were explored through a combination of transcriptome study, transmission electron microscope (TEM) observation of mitochondria, pathway enrichment analysis, and interaction network analysis. In vivo experiments on mice involving HE, Masson, TUNEL and Immunofluorescence staining examinations were conducted to confirm the in vitro experimental results. When more than 30 pulses were applied, a continuous decline in post-ablation relative cell activity was observed, decreasing from 0.36 at 3 h to 0.13 (p < 0.01) at 48 h. Notably, at a voltage of 1500 V/cm and a pulse count of 50, the apoptosis rate exceeded 95%, coupled with a more stable and consistent cell ablation. Following ablation, a notable upregulation in mitochondria-related transcription levels was observed, accompanied by mitochondrial membrane disruption and an increase in Cytochrome C levels. Within a certain range, an increase in voltage and number of electric pulses corresponded to a greater quantity of cell mortality in the ablation zone. The µsPEFs induced cell injury by impairing mitochondrial function and potentially triggering the mitochondrial apoptosis pathway.

Thermal and Non-Thermal Energies for Atrial Fibrillation Ablation

The cornerstone of ablative therapy for atrial fibrillation (AF) is pulmonary vein isolation (PVI). Whether PVI should be added with additional lesions in persistent atrial fibrillation (PerAF) or for any post-ablative recurrent AF is a matter of debate. Whatever the ablative strategy, it must determine the choice of energy source to achieve the most durable lesion sets with the least likelihood of complications. Radiofrequency (RF) is the most studied thermal ablation technique. It can be combined with high-density electroanatomic mapping and can be used for both pulmonary and extrapulmonary atrial ablation. Cryoenergy is at least as effective as radiofrequency for PVI; it is rapid, relatively safe, and has a steep learning curve. Therefore, it has been proposed as a first-line approach for PVI-only procedures. More recently, a non-thermal technique based on the application of pulsed direct current (Pulsed Field Ablation-PFA) has been introduced. PFA causes cell death by opening cell membrane pores (electroporation) without a significant increase in tissue temperature. It is fast and does not alter the extracellular matrix as thermal techniques do, although it ends up causing long-lasting, transmural lesions. Most importantly, it is relatively selective on cardiac myocytes and therefore potentially safer than thermal techniques. Some PFA systems can be combined with electroanatomic mapping systems. However, as of now, it appears that these ablation technologies should be considered complementary rather than alternative for a number of practical and theoretical reasons.

Feasibility and Safety of Pulsed-Field Ablation for Persistent Atrial Fibrillation: A Prospective Study

INTRODUCTION

Pulsed-field ablation (PFA) is a novel nonthermal ablation approach using rapid electrical pulses to cause cardiac cell apoptosis via electroporation. Our study aims to investigate the feasibility and safety of PFA for persistent atrial fibrillation (PeAF).

METHODS

Thirty-two consecutive patients diagnosed with PeAF were enrolled in our study. All patients underwent PFA treatment using the strategy including pulmonary vein isolation (PVI), left atrial posterior wall (LAPW) isolation, cavotricuspid isthmus (CTI) block, and mitral isthmus (MI) block. Acute and follow-up procedure outcomes were evaluated, and adverse events related to the ablation procedure were also observed.

RESULTS

One-year survival free from atrial tachyarrhythmia post-ablation was 65.6%. Acute success rates for PVI, LAPW isolation, CTI block, and MI block were 100%, 100%, 96.9%, and 81.3%, respectively. Eleven cases (34.4%) experienced atrial tachyarrhythmia recurrence, with eight cases being atrial fibrillation (AF) recurrence and three cases being atrial flutter recurrence. Three patients underwent repeat ablation. Minor complications were encountered in four patients with asymptomatic cerebral lesions. Vagal responses were commonly observed during the procedure. No severe coronary vasospasm or severe hemolysis occurred in our cohort.

CONCLUSION

PFA with the strategy including PVI, LAPW isolation, CTI block, and MI block is feasible, safe, and associated with a high rate of freedom from atrial tachyarrhythmia recurrence at 1 year in patients with PeAF.

TRIAL REGISTRATION

This study registered at the Chinese Clinical Trial Registry (ChiCTR2300068980).

Pulsed field ablation in medicine: irreversible electroporation and electropermeabilization theory and applications

BACKGROUND

Focal ablation techniques are integral in the surgical intervention of diseased tissue, where it is necessary to minimize damage to the surrounding parenchyma and critical structures. Irreversible electroporation (IRE) and high-frequency IRE (H-FIRE), colloquially called pulsed-field ablation (PFA), utilize high-amplitude, low-energy pulsed electric fields (PEFs) to nonthermally ablate soft tissue. PEFs induce cell death through permeabilization of the cellular membrane, leading to loss of homeostasis. The unique nonthermal nature of PFA allows for selective cell death while minimally affecting surrounding proteinaceous structures, permitting treatment near sensitive anatomy where thermal ablation or surgical resection is contraindicated. Further, PFA is being used to treat tissue when tumor margins are not expected after surgical resection, termed margin accentuation. This review explores both the theoretical foundations of PFA, detailing how PEFs induce cell membrane destabilization and selective tissue ablation, the outcomes following treatment, and its clinical implications across oncology and cardiology.

CONCLUSIONS

Clinical experience is still progressing, but reports have demonstrated that PFA reduces complications often seen with thermal ablation techniques. Mounting oncology data also support that PFA produces a robust immune response that may prevent local recurrences and attenuate metastatic disease. Despite promising outcomes, challenges such as optimizing field delivery and addressing variations in tissue response require further investigation. Future directions include refining PFA protocols and expanding its application to other therapeutic areas like benign tissue hyperplasia and chronic bronchitis.

Esophageal Protection Strategies for Ablation of Atrial Fibrillation: Comparative Results of Consecutive Endoscopic Evaluation

BACKGROUND

Atrial-esophageal fistula following AF ablation remains a concern. There is no standardized approach to minimize its risk and morbidity.

OBJECTIVE

To present the seven-year experience of a systematic endoscopic surveillance of esophageal injury after AF catheter ablation.

METHODS

This is a retrospective single center registry of systematic endoscopic evaluation after AF ablation in consecutive procedures performed from 2016 to 2022. A p-value of <0.05 was considered statistically significant.

RESULTS

823 AF ablation with controlled esophagogastroduodenoscopy (EGD) were analyzed. Most patients (n=588, 71.4%) were male, 575 (69.9%) had paroxysmal AF. Esophageal temperature monitoring was performed using a single sensor in 310 patients (40.3%) and a multi-sensor probe in 306 (39.8%). Lesions were presented in 217 EGD (26.5%): hematoma-ecchymosis in 27 (3.3%), erythema in 14 (1.7%), erosion in 78 (9.5%) and ulcer in 67 (8.2%) patients. No esophageal protective strategy was associated with more ulcers, except the use of 8mm tip-catheter (14.7% of ulcers with 8mm tip catheter vs 6.7% with other catheters, p = 0.001). Thermal lesions were early detected and treated. Most lesions were considered healed at endoscopy, but one patient who underwent pulmonary vein isolation with an 8m tip catheter had esophageal fistula, treated successfully with endoscopic metal clip and endoloop technique.

CONCLUSION

The incidence of esophageal lesions at routine EGD following AF ablation is high, although in most of the cases they heal spontaneously. Patients who underwent ablation with the 8mm tip catheter had more severe thermal lesions. Early esophagus endoscopy may help the diagnosis of early-stage lesions and the prevention of fistula formation after AF ablation.

Dose-dependent ventricular lesion formation using a novel large-area pulsed field ablation catheter: A preclinical feasibility study

BACKGROUND

Pulsed field ablation (PFA) has shown promising data in terms of safety and procedural efficiency for pulmonary vein isolation. Large-area focal PFA catheter designs might be suitable to deliver deep and durable lesions in ventricular myocardium.

OBJECTIVE

We aimed to investigate the dose-response of a novel large-area focal 3-dimensional (3D)-enabled map-and-ablate PFA catheter for ventricular ablation in a chronic preclinical swine model.

METHODS

An 8F catheter with a 9-mm hexaspline tip was used for 3D mapping of both ventricles in a porcine model. Using a PFA generator with a proprietary waveform optimized for the catheter, left and right ventricular lesions were placed with either a monopolar or bipolar ablation vector and with 1, 2, or 4 applications per site (2.0 kV/application). Tissue contact was ensured by intracardiac echocardiography and electrograms. The animals were kept alive for 1 week. Ablation lesions were assessed macroscopically after triphenyl tetrazolium chloride staining and by histopathology.

RESULTS

A total of 69 chronic ventricular lesions from 7 pigs were available for analysis. By stacking 4 PFA applications rather than a single application, median chronic lesion depth increased from 4.8 mm (interquartile range [IQR], 4.1-5.6 mm) to 5.5 mm (IQR, 5.0-6.2 mm; P = .06) with bipolar ablation and from 4.9 mm (IQR, 4.4-5.2 mm) to 6.5 mm (IQR, 5.9-6.9 mm; P = .002) with monopolar ablation. On histologic evaluation, lesion borders were clearly demarcated, with vessels and nerves preserved.

CONCLUSION

A novel large-area focal ablation catheter with the ability for 3D mapping and PFA was able to create dose-dependent deep ventricular lesions durable 1 week after ablation.

Anatomical characteristics of mitral isthmus and its spatial relationship with the esophagus in patients undergoing atrial fibrillation ablation using CT angiography

Background

This study examines the anatomical characteristics of the mitral isthmus (MI) and its spatial relationship with the esophagus in patients undergoing atrial fibrillation ablation, using cardiovascular computed tomographic angiography (CTA). Understanding this relationship is crucial to minimize the risk of esophageal injuries during ablation procedures.

Methods

The investigation included 300 participants, divided into 200 subjects in the experimental group undergoing atrial fibrillation ablation and 100 in the control group. Detailed CTA scans were used to assess the MI's structure and proximity to the esophagus, employing various measurements like the MI's endocardial length, depth, and its relation to adjacent esophageal anatomy.

Results

The study revealed significant differences in the MI's length and distance measurements between the experimental and control groups, with the former showing greater dimensions, potentially influencing ablation strategies. A substantial proportion of patients exhibited close proximity or direct contact between the MI and the esophagus, emphasizing the importance of pre-procedural imaging in identifying risks for esophageal damage.

Conclusions

Pre-procedural cardiovascular CTA provides essential insights into the MI's anatomical details and its relation to the esophagus, aiding in the customization of ablation strategies to enhance procedural safety and efficacy. The findings highlight the significance of tailored imaging assessments to mitigate esophageal injury risks in atrial fibrillation ablation.

Fundamentals of System Design for Cardiac Pulsed Field Ablation: Optimization of Safety, Efficacy, and Usability

The goal of a cardiac pulsed field ablation (PFA) system is to provide safe, effective, and usable therapy for the treatment of cardiac arrhythmias. Achieving this goal is a complex exercise in system design, requiring optimization of catheter, waveform, and dosing. This optimization is often iterative, as myriad design factors are balanced to achieve the goal while making use of computational modeling, bench testing, preclinical animal studies, and human clinical studies to evaluate system performance. It is important for both engineers and clinicians to understand the fundamentals of cardiac PFA system design in order to partner to continuously improve performance of this expanding ablation modality.

Using a Novel Pulsed Field Ablation Technique to Identify the Critical Isthmus Within a Tachycardia Circuit

Pulsed field ablation uses irreversible electroporation to interrupt cellular membranes and induce myocyte apoptosis. Reversible electroporation has been used in other specialties, but its utility in cardiac ablation is unknown. Here, a 69-year-old woman undergoing repeat ablation for atypical atrial flutter presented with extensive scar after cardiac surgery (including MAZE) and previous ablation, leading to a macro re-entry circuit. To minimize superfluous lesions and further arrhythmia, we used a single pulse confirming the isthmus location, with cessation of the arrhythmia. As a conclusion, reversible electroporation may be used to test areas of interest prior to irreversible lesion creation.

Catheter ablation using pulsed-field energy: Advantages and limitations compared with conventional energy

Atrial fibrillation (AF) poses significant risks of heart failure and stroke, emphasizing effective treatment. Catheter ablation using thermal energy sources, such as radiofrequency or cryoballoon ablation, has shown greater success in maintaining sinus rhythm compared with drug therapy. However, thermal ablation (TA) is associated with serious complications, such as atrial-esophageal fistula, phrenic nerve palsy, and pulmonary vein stenosis. Pulsed-field ablation (PFA) is an emerging ablation energy source that uses electroporation to selectively target cardiac tissue while sparing adjacent structures such as nerves and blood vessels. Two randomized controlled trials have demonstrated that PFA is comparable to TA in both efficacy and safety at a 1-year follow-up and had shorter procedure times. A review of six meta-analyses consistently showed shorter procedural times for PFA across all studies. Additionally, three out of the four recent studies with large samples reported lower recurrence rates with PFA. Regarding complication rates, four out of four studies showed lower incidences of phrenic nerve injury with PFA, and two out of three studies reported lower rates of esophageal injury with PFA. However, four out of four studies indicated higher incidences of cardiac tamponade with PFA, highlighting the need for caution among early-career operators. Furthermore, careful monitoring is required considering the possible unforeseen complications specific to PFA and the lack of long-term follow-up data. Despite these concerns, PFA shows promise as a safer, more effective, and efficient alternative to TA for AF, particularly as operator experience and device technology continue to advance.

Lesion Formation in Cardiac Pulsed-Field Ablation: Acute to Chronic Cellular Level Changes

As pulsed-field ablation (PFA) emerges as a promising therapy for atrial arrhythmias, an understanding of the cellular injury to cardiac tissue is critical to evaluating and interpreting results for each PFA system. This review aims to detail the mechanism of cell death for PFA, compare the cell death mechanism to thermal ablation modalities, clarify common histology markers, detail the progression of PFA lesions from the acute, to subacute, to chronic maturation states, and discuss clinical indicators of PFA lesions.

Coronary artery injury in pulsed field ablation

PURPOSE OF REVIEW

Although pulsed field ablation (PFA) has emerged as an innovative nonthermal catheter ablation modality, recent reports raise concerns about its potential impact on nearby coronary arteries. This review provides a comprehensive overview of the current understanding and future directions regarding the effects of PFA on or near coronary arteries.

RECENT FINDINGS

Clinical studies have demonstrated the risks of acute transient vasospasm after delivery of PFA, especially with ablation of structures in proximity to the coronary arteries, such as the cavotricuspid and mitral isthmuses. The clinical incidence has been reported to be approximately 0.14%, according to the largest multicenter registry. Nitroglycerin pretreatment has been demonstrated to mitigate vasospastic events. However, early preclinical models indicate that chronic neointimal hyperplasia, tunica media fibrosis and mild coronary artery narrowing may occur, suggesting long-term coronary injury after delivering PFA near coronary arteries.

SUMMARY

Despite reducing collateral tissue damage compared with thermal methods, PFA near coronary arteries may require careful procedural planning and proactive use of nitroglycerin to reduce coronary vasospasm. Further research is essential to elucidate the mechanisms underlying PFA-induced coronary spasm, optimize catheter design and placement, and assess the long-term coronary health implications.

Contemporary Trends in Pulsed Field Ablation for Cardiac Arrhythmias

Pulsed field ablation (PFA) is a catheter-based procedure that utilizes short high voltage and short-duration electrical field pulses to induce tissue injury. The last decade has yielded significant scientific progress and quickened interest in PFA as an energy modality leading to the emergence of the clinical use of PFA technologies for the treatment of atrial fibrillation. It is generally agreed that more research is needed to improve our biophysical understanding of PFA for clinical cardiac applications as well as its potential as a potential alternative energy source to thermal ablation modalities for the treatment of other arrhythmias. In this review, we discuss the available preclinical and clinical evidence for PFA for atrial fibrillation, developments for ventricular arrhythmia (VA) ablation, and future perspectives.

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.

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 for paroxysmal atrial fibrillation with mitral and cavotricuspid isthmus‑dependent atrial flutter: A case report

Pulsed field ablation (PFA), a nonthermal ablative mechanism, has been proven to be effective and safe in clinical application. To date, PFA has been used for only atrial fibrillation (AF) ablation in limited clinical trials. The present study describes a case of paroxysmal AF in which mitral and cavotricuspid isthmus (CTI)-dependent atrial flutter was discovered incidentally during PFA operation and successfully ablated with PFA. This is the first medical record of PFA for AF combined with mitral and CTI atrial flutter. The present case report revealed that PFA can be independently used to treat complex arrhythmias, similar to radiofrequency (RF) ablation, without the need for assistance from other ablation methods. Concurrently, the present study, to the best of the authors' knowledge is the first to report a case using a point-to-point PFA ablation strategy for isthmus ablation. This highlights the potential of PFA in treating diverse arrhythmias across different regions, such as the mitral isthmus and other intricate areas, utilizing a point-to-point PFA ablation strategy.

Surveillance of esophageal injury after atrial fibrillation catheter ablation

AIMS

Atrial-esophageal fistula following ablation procedures for atrial fibrillation (AF) remains a major concern. There is no standardized approach to minimize the risk and morbidity of this serious complication. The objective of this study was to present the 7-year experience of systematic endoscopic surveillance of esophageal injury after AF catheter ablation.

METHODS

This was a retrospective single-center registry of systematic endoscopic evaluations after consecutive AF ablation procedures performed from 2016 to 2022.

RESULTS

A total of 677 AF ablation procedures with controlled esophagogastroduodenoscopy (EGD) were analyzed during that period. Most patients were male (71%) with paroxysmal AF (71%). Radiofrequency with electroanatomical mapping was the main ablation approach for 633 patients (93.5%). Esophageal temperature monitoring was performed using a single sensor in 220 patients (34.3%) and a multisensor probe in 296 patients (46%). Most of the patients presented no esophageal lesions (75,7%). Severe lesions (Kansas-city-classification KCC 2B) were found in 46 (6.8%) of them, requiring a new EGD in 7 days. KCC2B lesions were persistent in 3 patients, 2 of whom had ulcers during healing and 1 patient with a deep ulcer of 10 mm who was admitted to the hospital and underwent fasting and parenteral nutrition. The ulcer healed in the second week after the procedure. Both esophageal temperature monitoring strategies were equivalent at preventing thermal lesions. Additionally, a greater left atrium (LA) was associated with a lower incidence of esophageal ulcer (P = 0.028). Most of the lesions spontaneously healed.

CONCLUSION

The incidence of esophageal injury after ablation was 24.3%. Most (72%) were mild lesions that required no therapeutic intervention. A larger left atrium (LA) was correlated with a lower incidence of thermal lesions. Early endoscopy can help diagnose severe esophageal lesions and may provide additional information for the surveillance of esophageal injury after AF ablation.

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.

Left atrial posterior wall isolation in addition to pulmonary vein isolation using a pentaspline catheter in pulsed-field ablation for atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Persistent atrial fibrillation (AF) may require extensive ablation strategies. Left atrial posterior wall isolation (LAPWI) might address potential substrates for recurrence during pulsed-field ablation (PFA).

OBJECTIVE

This meta-analysis aimed to investigate the feasibility and effectiveness of LAPWI in addition to pulmonary vein isolation (PVI) using a pentaspline catheter in PFA for AF.

METHODS

Comprehensive search was conducted using PubMed, SCOPUS, ScienceDirect, and EuropePMC for studies reporting LAPWI+PVI using a pentaspline catheter in PFA ablation for AF. The primary outcome was atrial tachyarrhythmia (ATa) recurrence, defined as AF/atrial flutter/atrial tachycardia after blanking period.

RESULTS

There were 882 patients from 7 studies. The success rate of LAPWI was 100% using mean/median of 16 to 20 added PFA applications with no reported acute left atrial posterior wall reconnection and esophageal complications. In mean follow-up of 240 ± 91 days, ATa recurrence was 21% (95% CI 13%-29%; I2 = 84.8%) in the LAPWI+PVI group. Meta-regression analysis showed that age, left ventricular ejection fraction, and repeat procedure did not significantly influence ATa recurrence (P > .05). Each 1-mm increase in left atrial diameter, increases the chance of ATa recurrence by 6% (R2 = 100%, P < .001, I2 = 0%). Meta-analysis showed no difference in terms of ATa recurrence among LAPWI+PVI patients compared with those without LAPWI (odds ratio 0.78, 95% confidence interval 0.50-1.21, P = .27; I2 = 0%, P = .86). Procedure time and fluoroscopy time did not significantly differ (P > .05).

CONCLUSION

LAPWI using a pentaspline catheter during PFA was feasible and did not prolong the procedure/fluoroscopy but did not reduce ATa recurrence. LAPWI may be considered during PFA, although the benefit is uncertain.

Pulsed Field Ablation of Atrial Fibrillation: A Novel Technology for Safer and Faster Ablation

Atrial fibrillation (AF), the most common arrhythmia, is associated with increased morbidity, mortality, and healthcare costs. Evidence indicates that rhythm control offers superior cardiovascular outcomes compared to rate control, especially when initiated early after the diagnosis of AF. Catheter ablation remains the single best therapy for AF; however, it is not free from severe complications and only a small percentage of AF patients in the Western world ultimately receive ablation. Ensuring that AF ablation is safe, effective, and efficient is essential to make it accessible to all patients. With the limitations of traditional thermal ablative energies, pulsed field ablation (PFA) has emerged as a novel non-thermal energy source. PFA targets irreversible electroporation of cardiomyocytes to achieve cell death without damaging adjacent structures. Through its capability to create rapid, selective lesions in myocytes, PFA presents a promising alternative, offering enhanced safety, reduced procedural times, and comparable, if not superior, efficacy to thermal energies. The surge of new evidence makes it challenging to stay updated and understand the possibilities and challenges of PFA. This review aims to summarize the most significant advantages of PFA and how this has translated to the clinical arena, where four different catheters have received CE-market approval for AF ablation. Further research is needed to explore whether adding new ablation targets, previously avoided due to risks associated with thermal energies, to pulmonary vein isolation can improve the efficacy of AF ablation. It also remains to see whether a class effect exists or if different PFA technologies can yield distinct clinical outcomes given that the optimization of PFA parameters has largely been empirical.

Pulsed Field Ablation: A Comprehensive Update

One of the recent advancements in the field of cardiac electrophysiology is pulsed field ablation (PFA). PFA is a novel energy modality that does not rely on thermal processes to achieve ablation which, in turn, results in limited collateral damage to surrounding structures. In this review, we discuss the mechanisms, safety, efficacy, and clinical applications of PFA for the management of atrial and ventricular arrhythmias. We also summarize the published pre-clinical and clinical studies regarding this new technology.

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.

Comparative Efficacy and Safety of Pulsed Field Ablation Versus Radiofrequency Ablation of Idiopathic LV Arrhythmias

BACKGROUND

Comparative efficacy and safety data on radiofrequency ablation (RFA) versus pulsed field ablation (PFA) for common idiopathic left ventricular arrhythmia (LV-VAs) locations are lacking.

OBJECTIVES

This study sough to compare RFA with PFA of common idiopathic LV-VAs locations.

METHODS

Ten swine were randomized to PFA or RFA of LV interventricular septum, papillary muscle, LV summit via distal coronary sinus, and LV epicardium via subxiphoid approach. Ablations were delivered using an investigational dual-energy (RFA/PFA) contact force (CF) and local impedance-sensing catheter. After 1-week survival, animals were euthanized for lesion assessment.

RESULTS

A total of 55 PFA (4 applications/site of 2.0 KV, target CF ≥10 g) and 36 RFA (CF ≥10 g, 25-50 W targeting ≥50 Ω local impedance drop, 60-second duration) were performed. LV interventricular septum: average PFA depth 7.8 mm vs RFA 7.9 mm (P = 0.78) and no adverse events. Papillary muscle: average PFA depth 8.1 mm vs RFA 4.5 mm (P < 0.01). Left ventricular summit: average PFA depth 5.6 mm vs RFA 2.7 mm (P < 0.01). Steam-pop and/or ventricular fibrillation in 4 of 12 RFA vs 0 of 12 PFA (P < 0.01), no ST-segment changes observed. Epicardium: average PFA depth 6.4 mm vs RFA 3.3 mm (P < 0.01). Transient ST-segment elevations/depressions occurred in 4 of 5 swine in the PFA arm vs 0 of 5 in the RFA arm (P < 0.01). Angiography acutely and at 7 days showed normal coronaries in all cases.

CONCLUSIONS

In this swine study, compared with RFA, PFA of common idiopathic LV-VAs locations produced deeper lesions with fewer steam pops. However, PFA was associated with higher rates of transient ST-segment elevations and depressions with direct epicardium ablation.

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 .

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.

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.

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. A novel "single-shot" map-and-ablate spherical multielectrode PFA array catheter that is able to verify electrode-tissue contact was recently studied in a first-in-human trial of atrial fibrillation (AF).

OBJECTIVE

The aim of this study was to report lesion durability data, safety, and 12-month effectiveness outcomes.

METHODS

The spherical PFA catheter, an all-in-one mapping and ablation system, was used to render anatomy and to deliver biphasic pulses (ungated 1.7 kV pulses; ∼40 seconds/application). Ablation sites included pulmonary veins (PVs) and, in selected patients, posterior wall and mitral isthmus. Follow-up was invasive remapping at ∼3 months, electrocardiograms, Holter monitoring at 6 and 12 months, and symptomatic and scheduled transtelephonic monitoring. The primary and secondary efficacy end points were acute PV isolation (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), posterior wall (n = 20; 3.6 applications/posterior wall), and mitral isthmus (n = 11; 2.9 applications/mitral isthmus). Lesions were acutely successful for all 187 of 187 PVs (100%), 20 of 20 posterior walls (100%), and 10 of 11 mitral isthmuses (91%). Pulse delivery time, left atrial catheter dwell time, and procedure time were 61.5 ± 32.8 seconds, 53.9 ± 26.5 minutes, and 87.8 ± 29.8 minutes, respectively. Remapping (43/48 patients [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.

Pulsed Field vs Conventional Thermal Ablation for Paroxysmal Atrial Fibrillation: Recurrent Atrial Arrhythmia Burden

BACKGROUND

The ADVENT randomized trial revealed no significant difference in 1-year freedom from atrial arrhythmias (AA) between thermal (radiofrequency/cryoballoon) and pulsed field ablation (PFA). However, recent studies indicate that the postablation AA burden is a better predictor of clinical outcomes than the dichotomous endpoint of 30-second AA recurrence.

OBJECTIVES

The goal of this study was to determine: 1) the impact of postablation AA burden on outcomes; and 2) the effect of ablation modality on AA burden.

METHODS

In ADVENT, symptomatic drug-refractory patients with paroxysmal atrial fibrillation underwent PFA or thermal ablation. Postablation transtelephonic electrocardiogram monitor recordings were collected weekly or for symptoms, and 72-hour Holters were at 6 and 12 months. AA burden was calculated from percentage AA on Holters and transtelephonic electrocardiogram monitors. Quality-of-life assessments were at baseline and 12 months.

RESULTS

From 593 randomized patients (299 PFA, 294 thermal), using aggregate PFA/thermal data, an AA burden exceeding 0.1% was associated with a significantly reduced quality of life and an increase in clinical interventions: redo ablation, cardioversion, and hospitalization. There were more patients with residual AA burden <0.1% with PFA than thermal ablation (OR: 1.5; 95% CI: 1.0-2.3; P = 0.04). Evaluation of outcomes by baseline demographics revealed that patients with prior failed class I/III antiarrhythmic drugs had less residual AA burden after PFA compared to thermal ablation (OR: 2.5; 95% CI: 1.4-4.3; P = 0.002); patients receiving only class II/IV antiarrhythmic drugs pre-ablation had no difference in AA burden between ablation groups.

CONCLUSIONS

Compared with thermal ablation, PFA more often resulted in an AA burden less than the clinically significant threshold of 0.1% burden. (The FARAPULSE ADVENT PIVOTAL Trial PFA System vs SOC Ablation for Paroxysmal Atrial Fibrillation [ADVENT]; NCT04612244).

Ablating Myocardium Using Nanosecond Pulsed Electric Fields: Preclinical Assessment of Feasibility, Safety, and Durability

BACKGROUND

Unlike conventional microsecond pulsed electrical fields that primarily target the cell membranes, nanosecond pulses are thought to primarily electroporate intracellular organelles. We conducted a comprehensive preclinical assessment of catheter-based endocardial nanosecond pulsed field ablation in swine.

METHODS

A novel endocardial nanosecond pulsed field ablation system was evaluated in a total of 25 swine. Using either a low-dose (5-second duration) or high-dose (15-second duration) strategy, thoracic veins and discrete atrial and ventricular sites were ablated. Predetermined survival periods were <1 (n=1), ≈2 (n=7), ≈7 (n=6), 14 (n=2), or ≈28 (n=9) days, and venous isolation was assessed before euthanasia. Safety assessments included evaluation of esophageal effects, phrenic nerve function, and changes in venous caliber. All tissues were subject to careful gross pathological and histopathologic examination.

RESULTS

All (100%) veins (13 low-dose, 34 high-dose) were acutely isolated, and all reassessed veins (6 low-dose, 15 high-dose) were durably isolated. All examined vein lesions (10 low-dose, 22 high-dose) were transmural. Vein diameters (n=15) were not significantly changed. Of the animals assessed for phrenic palsy (n=9), 3 (33%) demonstrated only transient palsy. There were no differences between dosing strategies. Thirteen mitral isthmus lesions were analyzed, and all 13 (100%) were transmural (depth, 6.4±0.4 mm). Ventricular lesions were 14.7±4.5 mm wide and 7.1±1.3 mm deep, with high-dose lesions deeper than low-dose (7.9±1.2 versus 6.2±0.8 mm; P=0.007). The esophagus revealed nontransmural adventitial surface lesions in 5 of 5 (100%) animals euthanized early (2 days) post-ablation. In the 10 animals euthanized later (14-28 days), all animals demonstrated significant esophageal healing-8 with complete resolution, and 2 with only trace fibrosis.

CONCLUSIONS

A novel, endocardial nanosecond pulsed field ablation system provides acute and durable venous isolation and linear lesions. Transient phrenic injury and nontransmural esophageal lesions can occur with worst-case assessments suggesting limits to pulsed field ablation tissue selectivity and the need for dedicated assessments during clinical studies.

Safety of pulsed field ablation in more than 17,000 patients with atrial fibrillation in the MANIFEST-17K study

Pulsed field ablation (PFA) is an emerging technology for the treatment of atrial fibrillation (AF), for which pre-clinical and early-stage clinical data are suggestive of some degree of preferentiality to myocardial tissue ablation without damage to adjacent structures. Here in the MANIFEST-17K study we assessed the safety of PFA by studying the post-approval use of this treatment modality. Of the 116 centers performing post-approval PFA with a pentaspline catheter, data were received from 106 centers (91.4% participation) regarding 17,642 patients undergoing PFA (mean age 64, 34.7% female, 57.8% paroxysmal AF and 35.2% persistent AF). No esophageal complications, pulmonary vein stenosis or persistent phrenic palsy was reported (transient palsy was reported in 0.06% of patients; 11 of 17,642). Major complications, reported for ~1% of patients (173 of 17,642), were pericardial tamponade (0.36%; 63 of 17,642) and vascular events (0.30%; 53 of 17,642). Stroke was rare (0.12%; 22 of 17,642) and death was even rarer (0.03%; 5 of 17,642). Unexpected complications of PFA were coronary arterial spasm in 0.14% of patients (25 of 17,642) and hemolysis-related acute renal failure necessitating hemodialysis in 0.03% of patients (5 of 17,642). Taken together, these data indicate that PFA demonstrates a favorable safety profile by avoiding much of the collateral damage seen with conventional thermal ablation. PFA has the potential to be transformative for the management of patients with AF.

Autonomic Effects of Pulsed Field vs Thermal Ablation for Treating Atrial Fibrillation: Subanalysis of ADVENT

BACKGROUND

Autonomic denervation is an ancillary phenomenon during thermal ablation of atrial fibrillation (AF), that may have synergistic effects on symptomatic improvement and long-term freedom from AF. Pulsed field ablation (PFA), a nonthermal ablation modality, was noninferior to thermal ablation in treating AF; however, PFA's relative myocardial selectivity may minimize autonomic effects.

OBJECTIVES

This study sought to compare heart rate (HR) and heart rate variability (HRV) metrics as markers of autonomic function after ablation using PFA vs thermal ablation.

METHODS

ADVENT (FARAPULSE ADVENT PIVOTAL Trial PFA System vs SOC Ablation for Paroxysmal Atrial Fibrillation) was a randomized pivotal study comparing PFA (pentaspline catheter) with thermal ablation (radiofrequency [RF] or cryoballoon [CB]) for treating paroxysmal AF. Baseline HR was acquired from a pre-ablation 12-lead electrocardiogram, whereas follow-up HRs, as well as HRV (standard deviation of all normal to normal RR intervals, standard deviation of 5-minute average RR intervals) metrics, were derived from 72-hour Holter monitors at 6 and 12 months.

RESULTS

This study included 379 paroxysmal AF patients undergoing PFA (n = 194) or thermal ablation (n = 185; n = 102 RF, n = 83 CB) completing 6- and 12-month Holter monitoring. Compared with PFA, thermal patients had significantly greater increases in HR from baseline to 6 months (ΔHR; 10.1 vs 5.9 beats/min; P = 0.02) and 12 months (ΔHR; 8.8 vs 5.2 beats/min; P = 0.03). This increase in HR at 6 and 12 months was similar between CB and RF (P = 0.94 and 0.83, respectively). HRV, both standard deviation of all normal to normal RR intervals and standard deviation of 5-minute average RR intervals, were significantly lower at both 6 and 12 months after thermal ablation compared with PFA (P < 0.01).

CONCLUSIONS

PFA's effect on the autonomic nervous system was attenuated compared with thermal ablation. Whether this affects long-term freedom from AF or symptomatic bradycardia/pauses after AF ablation requires further study.

Initial real-world data on catheter ablation in patients with persistent atrial fibrillation using the novel lattice-tip focal pulsed-field ablation catheter

AIMS

Technological advancements have contributed to the enhanced precision and lesion flexibility in pulsed-field ablation (PFA) by integrating a three-dimensional mapping system combined with a point-by-point ablation strategy. Data regarding the feasibility of this technology remain limited to some clinical trials. This study aims to elucidate initial real-world data on catheter ablation utilizing a lattice-tip focal PFA/radiofrequency ablation (RFA) catheter in patients with persistent atrial fibrillation (AF).

METHODS AND RESULTS

Consecutive patients who underwent catheter ablation for persistent AF via the lattice-tip PFA/RFA catheter were enrolled. We evaluated acute procedural data including periprocedural data as well as the clinical follow-up within a 90-day blanking period. In total, 28 patients with persistent AF underwent AF ablation either under general anaesthesia (n = 6) or deep sedation (n = 22). In all patients, pulmonary vein isolation was successfully achieved. Additional linear ablations were conducted in 21 patients (78%) with a combination of successful anterior line (n = 13, 46%) and roof line (n = 19, 68%). The median procedural and fluoroscopic times were 97 (interquartile range, IQR: 80-114) min and 8.5 (IQR: 7.2-9.5) min, respectively. A total of 27 patients (96%) were interviewed during the follow-up within the blanking period, and early recurrent AF was documented in four patients (15%) including one case of recurrent AF during the hospital stay. Neither major nor minor procedural complication occurred.

CONCLUSION

In terms of real-world data, our data confirmed AF ablation feasibility utilizing the lattice-tip focal PFA/RFA catheter in patients with persistent AF.

Multidisciplinary management strategies for atrial fibrillation

There has been a significant increase in the prevalence of atrial fibrillation (AF) over the past 30 years. Pulmonary vein isolation (PVI) is an effective treatment for AF, but research investigations have shown that AF recurrence still occurs in a significant number of patients after ablation. Heart rhythm outcomes following catheter ablation are correlated with numerous clinical factors, and researchers developed predictive models by integrating risk factors to predict the risk of recurrence of atrial fibrillation. The purpose of this article is to outline the risk scores for predicting cardiac rhythm outcomes after PVI and to discuss the modifiable factors that increase the risk of recurrence of AF, with the hope of further improving catheter ablation efficacy through preoperative identification of high-risk populations and postoperative management of modifiable risk factors.

Nitroglycerin to Ameliorate Coronary Artery Spasm During Focal Pulsed-Field Ablation for Atrial Fibrillation

BACKGROUND

In treating atrial fibrillation, pulsed-field ablation (PFA) has comparable efficacy to conventional thermal ablation, but with important safety advantages: no esophageal injury or pulmonary vein stenosis, and rare phrenic nerve injury. However, when PFA is delivered in proximity to coronary arteries using a pentaspline catheter, which generates a broad electrical field, severe vasospasm can be provoked.

OBJECTIVES

The authors sought to study the vasospastic potential of a focal PFA catheter with a narrower electrical field and develop a preventive strategy with nitroglycerin.

METHODS

During atrial fibrillation ablation, a focal PFA catheter was used for cavotricuspid isthmus ablation. Angiography of the right coronary artery (some with fractional flow reserve measurement) was performed before, during, and after PFA. Beyond no nitroglycerin (n = 5), and a few testing strategies (n = 8), 2 primary nitroglycerin administration strategies were studied: 1) multiple boluses (3-2 mg every 2 min) into the right atrium (n = 10), and 2) a bolus (3 mg) into the right atrium with continuous peripheral intravenous infusion (1 mg/min; n = 10).

RESULTS

Without nitroglycerin, cavotricuspid isthmus ablation provoked moderate-severe vasospasm in 4 of 5 (80%) patients (fractional flow reserve 0.71 ± 0.08). With repetitive nitroglycerin boluses, severe spasm did not occur, and mild-moderate vasospasm occurred in only 2 of 10 (20%). Using the bolus + infusion strategy, severe and mild-moderate spasm occurred in 1 and 3 of 10 patients (aggregate 40%). No patient had ST-segment changes.

CONCLUSIONS

Ablation of the cavotricuspid isthmus using a focal PFA catheter routinely provokes right coronary vasospasm. Pretreatment with high doses of parenteral nitroglycerin prevents severe spasm.

Impact of Left Atrial Posterior Wall Ablation During Pulsed-Field Ablation for Persistent Atrial Fibrillation

BACKGROUND

Pulmonary vein isolation (PVI) alone is insufficient to treat many patients with persistent atrial fibrillation (PersAF). Adjunctive left atrial posterior wall (LAPW) ablation with thermal technologies has revealed lack of efficacy, perhaps limited by the difficulty in achieving lesion durability amid concerns of esophageal injury.

OBJECTIVES

This study aims to compare the safety and effectiveness of PVI + LAPW ablation vs PVI in patients with PersAF using pulsed-field ablation (PFA).

METHODS

In a retrospective analysis of the MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-approval Clinical Use of Pulsed Field Ablation) registry, we studied consecutive PersAF patients undergoing post-approval treatment with a pentaspline PFA catheter. The primary effectiveness outcome was freedom from any atrial arrhythmia of ≥30 seconds. Safety outcomes included the composite of acute and chronic major adverse events.

RESULTS

Of the 547 patients with PersAF who underwent PFA, 131 (24%) received adjunctive LAPW ablation. Compared to PVI-alone, patients receiving adjunctive LAPW ablation were younger (65 vs 67 years of age, P = 0.08), had a lower CHA2DS2-VASc score (2.3 ± 1.6 vs 2.6 ± 1.6, P = 0.08), and were more likely to receive electroanatomical mapping (48.1% vs 39.0%, P = 0.07) and intracardiac echocardiography imaging (46.1% vs 17.1%, P < 0.001). The 1-year Kaplan-Meier estimate for freedom from atrial arrhythmias was not statistically different between groups in the full (PVI + LAPW: 66.4%; 95% CI: 57.6%-74.4% vs PVI: 73.1%; 95% CI: 68.5%-77.2%; P = 0.68) and propensity-matched cohorts (PVI + LAPW: 71.7% vs PVI: 68.5%; P = 0.34). There was also no significant difference in major adverse events between the groups (2.2% vs 1.4%, respectively, P = 0.51).

CONCLUSIONS

In patients with PersAF undergoing PFA, as compared to PVI-alone, adjunctive LAPW ablation did not improve freedom from atrial arrhythmia at 12 months.

Novel Ablation Catheters for Atrial Fibrillation

Various ablation technologies with different energy sources are currently being either used or being investigated for atrial fibrillation (AF) ablation. Potential complications continue to occur due to the indiscriminate thermal effects on non-targeted tissues adjacent to the myocardium that are common to all thermal ablation modalities. Pulsed field ablation (PFA) has recently gained significant attention and interest as an approach to AF ablation. PFA uniquely has the ability to circumvent certain complications related to thermal energy. PFA is a non-thermal ablation modality with the potential for unique-tissue selectivity that can minimize damage to collateral cardiac structures. Several PFA systems for AF ablation are currently being investigated. Some PFA systems have been designed to serve as single-shot approaches to achieve pulmonary vein isolation (PVI), and others have focal designs enabling flexible PVI lesion sets as well as linear/focal ablations. Favorable acute success rates and low incidence of complications with short procedure times have been reported with several PFA systems regardless of catheter design (single-shot or focal catheter). Clinical PFA studies in which chronic remapping was conducted, demonstrated pulmonary vein (PV) durability improved with evolutional modifications of pulsed field waveforms/dosing, achieving over 90% PV durability with optimized waveforms. Rare adverse events related to PFA may surface with its increasing use worldwide and as sicker patients get exposed to PFA. We believe that both excitement and vigilance are in order as we embark on yet another new chapter of AF ablation.

Ablation of Paroxysmal Atrial Fibrillation: between Present and Future

Pulmonary vein isolation (PVI) is the established cornerstone for atrial fibrillation (AF) ablation, indeed current guidelines recognize PVI as the gold standard for first-time AF ablation, regardless of if it is paroxysmal or persistent. Since 1998 when Haïssaguerre pioneered AF ablation demonstrating a burden reduction after segmental pulmonary vein (PV) ablation, our approach to PVI was superior in terms of methodology and technology. This review aims to describe how paroxysmal atrial fibrillation ablation has evolved over the last twenty years. We will focus on available techniques, a mechanistic understanding of paroxysmal AF genesis and the possibility of a tailored approach for the treatment of AF, before concluding with a future perspective.

Prospective 1-year results of atrial fibrillation ablation using the pentaspline pulsed field ablation catheter: The initial French experience

BACKGROUND

Pulsed field ablation has recently emerged as an interesting non-thermal energy for atrial fibrillation ablation. At a time of rapid spread of this technology, there is still a lack of prospective real-life data.

AIM

To describe multicentre prospective safety and 1-year efficacy data in three of the first French centres to use pulsed field ablation.

METHODS

All consecutive patients undergoing a first pulsed field ablation were included prospectively. The primary outcome was freedom from documented atrial arrhythmia. The safety endpoint was a composite of major adverse events. Univariate and multivariable analyses, including patient and procedural characteristics, were performed to identify factors predictive of recurrence.

RESULTS

Between May 2021 and June 2022, 311 patients were included (paroxysmal atrial fibrillation in 53%, persistent atrial fibrillation in 35% and long-standing persistent atrial fibrillation in 11%). Additional non-pulmonary vein pulsed field ablation applications were performed in 104/311 patients. One-year freedom from arrhythmia recurrence was 77.6% in the overall population and was significantly higher in patients with paroxysmal atrial fibrillation (88.4%) compared with patients with persistent atrial fibrillation (69.7%; P<0.001) and those with long-standing persistent atrial fibrillation (49.0%; P<0.001). The major complication rate was 2.6% (tamponade in four patients, stroke in two patients and coronary spasm in one patient). Besides the usual predictors of recurrences (left atrium size, CHA2DS2-VASc score, type of atrial fibrillation), the presence of atrial fibrillation at procedure start was independently associated with arrhythmia recurrence (hazard ratio: 2.04, 95% confidence interval: 1.10-3.77).

CONCLUSION

In this prospective multicentre real-world study, pulsed field ablation for atrial fibrillation ablation seems to be associated with a good safety profile and rather favourable acute and 1-year success rates.

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.

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.

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 .

A novel method for septal reduction therapy by three-dimensional guided transvenous intraseptal pulsed-field ablation

BACKGROUND

Pulsed-field ablation (PFA) is a nonthermal method for achieving selective cell death with little inflammation response. However, there are no reports of PFA for septal reduction therapy (SRT).

OBJECTIVE

The purpose of this study was to investigate the effectiveness and safety of PFA for SRT.

METHODS

A novel transvenous intraseptal PFA method with 3-dimensional (3D) guidance was introduced in Yorkshire pigs. Electrocardiographic parameters, transthoracic echocardiography, and histopathology were used to evaluated.

RESULTS

The maximum injury diameter of intramyocardial PFA increased with electric field intensity. After PFA, bipolar electrogram amplitude and pacing threshold measured by the PFA electrodes significantly decreased (F = 6.945, P = .007) or increased (F = 5.842, P = .024), respectively. In the ablated septal region, motion amplitude and systolic wall thickening rate significantly decreased and remained at low levels (motion amplitude: F = 20.793, P = .000; systolic wall thickening rate: F = 14.343, P = .000); however, septal thickness did not significantly change after PFA (F = 1.503, P = .248). Histologic examination showed specific cardiomyocyte death with gradually increased hyperchromatic cytoplasm and nuclear pyknosis, without obvious inflammatory cell infiltration in acute phase. TUNEL stain for fragmented DNA showed extensively positive in the ablation region 24 hours after PFA. During PFA, no sustained ventricular arrhythmia or atrioventricular conduction block occurred.

CONCLUSION

A novel intraseptal PFA method with 3D guidance was described. Intraseptal PFA resulted in effective myocardial injury and local hypokinesis without significant acute edema. Histologic examination showed widely programmed cardiomyocyte death with little inflammatory cell infiltration.

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.