Single shot electroporation of premature ventricular contractions from the right ventricular outflow tract

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.

Focal Pulsed Field Ablation for Premature Ventricular Contractions: A Multicenter Experience

BACKGROUND

Pulsed field ablation (PFA) is a novel technology for catheter-based atrial arrhythmia treatment. Evidence of its application for ventricular arrhythmia ablation is still limited. In this study, we describe the feasibility and efficacy of focal PFA for premature ventricular contraction (PVC) ablation.

METHODS

A prospective cohort of 20 patients referred for PVC ablation at 2 centers was enrolled, regardless of the presence of structural heart disease, PVC morphology, or previous ablation attempts. All procedures were performed using the CENTAURI System in combination with contact force sensing catheters and 3-dimensional electroanatomical mapping systems. Energy output and the number of applications were left to the operator's discretion.

RESULTS

Eleven (55%) procedures were conducted under general anesthesia, 6 (30%) under deep sedation, and 3 (15%) under light sedation. Muscular contraction was observed in one case (5%). Median procedural and fluoroscopy times were 95.5 and 6.55 minutes, respectively. The median number of PFA applications was 8 with a median contact force of 10g. A statistically significant (76%) reduction was observed in mean peak-to-peak bipolar electrogram voltage before and after ablation (0.707 versus 0.098 mV; P=0.008). Ventricular irritative firing was observed in 11 (55%) patients after PFA. The median follow-up was 120 days. Acute procedural success was achieved in 17 of 20 (85% [95% CI, 0.70-1]) patients. Two of the patients with procedural failure had late success with >80% clinical PVC burden suppression during follow-up, and 2 of 17 patients with acute success had late PVC recurrence, which accounts for a total of 17 of 20 (85% [95% CI, 0.70-1]) patients with chronic success. Transient ST-segment depression occurred in 1 patient, and the right bundle branch block was induced in 2 others (permanently only in one case).

CONCLUSIONS

PVC ablation using a focal PFA is feasible, effective, and safe, with promising acute and long-term results in several ventricular locations. Irritative firing is frequently observed. Coronary evaluation should be considered when targeting the outflow tract.

Ablation of accessory pathways in different anatomic locations using focal pulsed field ablation

BACKGROUND

Ablation of accessory pathways (APs) is the cornerstone for treatment of patients with Wolff-Parkinson-White syndrome and manifestation of atrioventricular reentrant tachycardia. Pulsed field ablation (PFA) is a new type of nonthermal energy source delivered to the underlying tissue via the ablation catheter and used for ablation of arrhythmic substrates.

OBJECTIVE

The purpose of this study was to determine the efficiency and long-term outcome of ablation of APs of different localizations using a focal pulsed electrical field.

METHODS

Electrophysiological study was performed in patients with indication for AP ablation. An ablation catheter was used to map the position of AP insertion. Pulsed electric field was delivered through a standard ablation catheter. In left-sided APs, the first ablation attempt was within the coronary sinus (CS). Patient follow-up was scheduled 1-3 months after the ablation. Additional check-up was performed after 6 and 12 months.

RESULTS

Fourteen 14 patients (3 pediatric) were treated. Termination of AP conduction was achieved in all procedures. The cohort consisted of 3 right free wall, 3 posteroseptal, and 8 left-sided APs. Ablation through CS was successfully used in 7 of 8 patients with left-sided APs. No complications were reported. Median follow-up was 5.5 months. Conduction recurrence through AP was documented in 1 patient.

CONCLUSION

Focal PFA for AP shows promising results in terms of efficacy and safety. A high rate of successful termination of left-sided APs by ablation within CS may represent a new standard approach. The safety and efficacy profile of PFA seems to be transferable to the pediatric population.

Technological advances in ventricular tachycardia catheter ablation: the relentless quest for novel solutions to old problems

BACKGROUND

Several novel technologies allowing catheter ablation (CA) with a favorable safety/efficacy profile have been recently developed, but not yet extensively clinically tested in the setting of ventricular tachycardia CA.

METHODS

In this technical report, we overview technical aspects and preclinical/clinical information concerning the application of three novel CA technologies in the ventricular milieu: a pulsed field ablation (PFA) generator (CENTAURI™, Galaxy Medical) to be used with linear, contact force-sensing radiofrequency ablation catheters; a contact force-sensing radiofrequency ablation catheter equipped with six thermocouples and three microelectrodes (QDOT Micro™, Biosense-Webster), allowing high-resolution mapping and temperature-controlled CA; and a flexible and mesh-shaped irrigation tip, contact force-sensing radiofrequency ablation catheter (Tactiflex, Abbott). We also report three challenging VT cases in which CA was performed using these technologies.

RESULTS

The CENTAURI system was used with the Tacticath™ (Abbott) ablation catheter to perform ventricular PFA in a patient with advanced heart failure, electrical storm, and a deep intramural septal substrate. Microelectrode mapping using QDOT Micro™ helped to refine substrate assessment in a VT patient with congenitally corrected transposition of the great arteries, and allowed the identification of the critical components of the VT circuit, which were successfully ablated. Tactiflex™ was used in two challenging CA cases (one endocardial and one epicardial), allowing acute and mid-term control of VT episodes without adverse events.

CONCLUSION

The ideation and development of novel technologies initially intended to treat atrial arrhythmias and successfully implemented in the ventricular milieu is contributing to the progressive improvement in the clinical benefits derived from VT CA, making this procedure key for successful management of increasingly complex patients.

Opportunities and Challenges in Catheter-Based Irreversible Electroporation for Ventricular Tachycardia

The use of catheter-based irreversible electroporation in clinical cardiac laboratories, termed pulsed-field ablation (PFA), is gaining international momentum among cardiac electrophysiology proceduralists for the non-thermal management of both atrial and ventricular tachyrhythmogenic substrates. One area of potential application for PFA is in the mitigation of ventricular tachycardia (VT) risk in the setting of ischemia-mediated myocardial fibrosis, as evidenced by recently published clinical case reports. The efficacy of tissue electroporation has been documented in other branches of science and medicine; however, ventricular PFA's potential advantages and pitfalls are less understood. This comprehensive review will briefly summarize the pathophysiological mechanisms underlying VT and then summarize the pre-clinical and adult clinical data published to date on PFA's effectiveness in treating monomorphic VT. These data will be contrasted with the effectiveness ascribed to thermal cardiac ablation modalities to treat VT, namely radiofrequency energy and liquid nitrogen-based cryoablation.

Twenty-five years of catheter ablation of ventricular tachycardia: a look back and a look forward

This article will discuss the past, present, and future of ventricular tachycardia ablation and the continuing contribution of the Europace journal as the platform for publication of milestone research papers in this field of ventricular tachycardia ablation.

First worldwide use of pulsed-field ablation for ventricular tachycardia ablation via a retrograde approach

INTRODUCTION

We present the first worldwide use of pulsed-field ablation (PFA) for ventricular tachycardia (VT) ablation via a retrograde approach.

METHODS

The patient had previously failed conventional ablation of an intramural circuit underneath the aortic valve. The same VT circuit was inducible during the procedure. The Farawave PFA catheter and Faradrive sheath were used to deliver PFA applications.

RESULTS

Post ablation mapping demonstrated scar homogenization. There was no evidence of coronary spasm during PFA applications and no other complications occurred. VT was non-inducible post ablation and the patient has remained free of arrhythmia at follow-up.

CONCLUSION

PFA for VT via a retrograde approach is feasible and effective.

Pulsed Field Ablation for Atrial Fibrillation

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

Potential Application of Pulsed Field Ablation in Ventricular Arrhythmias

Pulsed field ablation (PFA) is a new ablative method for the therapy of arrhythmia. Recent preclinical and clinical studies have already demonstrated the feasibility and safety of PFA for the treatment of atrial fibrillation (AF). However, the application of PFA may not be limited to the above fields. There are some data on the application of PFA on ventricular arrhythmias (VAs), such as ventricular fibrillation (VF) and ventricular tachycardia (VT). Further, a case report about PFA has been published recently, in which PFA was successfully applied to the ablation of premature ventricular contractions (PVCs) from the right ventricular outflow tract. Thus, we aimed to review recent research findings of PFA in ventricular ablation and evaluate the possibility of its application in VAs.

Coronary Arterial Spasm During Pulsed Field Ablation to Treat Atrial Fibrillation

BACKGROUND

Pulsed field ablation (PFA) has a unique safety profile when used to treat atrial fibrillation, largely related to its preferentiality for myocardial tissue ablation, in particular, esophageal sparing. A pentaspline catheter was the first such PFA system studied clinically for atrial fibrillation ablation; in these initial regulatory trials, the catheter was used for pulmonary vein isolation and left atrial posterior wall ablation. Since its regulatory approval in Europe, in clinical practice, physicians have ablated beyond pulmonary vein isolation and left atrial posterior wall ablation to expanded lesion sets in closer proximity to coronary arteries. This is an unstudied important issue because preclinical and clinical data have raised the potential for coronary arterial spasm. Herein, we studied the vasospastic potential of PFA lesion sets, both remote from and adjacent to coronary arteries.

METHODS

During routine atrial fibrillation ablation using the pentaspline PFA catheter, coronary angiography was performed before, during, and after pulsed field applications. The lesion sets studied included: (1) those remote from the coronary arteries such as pulmonary vein isolation (n=25 patients) and left atrial posterior wall ablation (n=5), and (2) ablation of the cavotricuspid isthmus (n=20) that is situated adjacent to the right coronary artery.

RESULTS

During pulmonary vein isolation and left atrial posterior wall ablation, coronary spasm did not occur, but cavotricuspid isthmus ablation provoked severe subtotal vasospasm in 5 of 5 (100%) consecutive patients, and this was relieved by intracoronary nitroglycerin in 5.5±3.5 minutes. ST-segment elevation was not observed. However, no patient (0%, P=0.004) had severe spasm if first administered parenteral nitroglycerin, either intracoronary (n=5) or intravenous (n=10), before treatment.

CONCLUSIONS

Coronary vasospasm was not provoked during PFA at locations remote from coronary arteries, but when the energy is delivered adjacent to a coronary artery, PFA routinely provokes subclinical vasospasm. This phenomenon is attenuated by nitroglycerin, administered either post hoc to treat spasm or as prophylaxis.

5S Study: Safe and Simple Single Shot Pulmonary Vein Isolation With Pulsed Field Ablation Using Sedation

BACKGROUND

Pulsed field ablation represents an energy source specific for ablation of cardiac arrhythmias including atrial fibrillation. The aim of the study was to describe the adoption and the process of streamlining procedures with a new ablation technology.

METHODS

All-comer atrial fibrillation patients (n=191; mean age 69±12 years) underwent catheter ablation with a pulsed field ablation ablation device exclusively using analog-sedation. In the validation phase (n=25), device electrogram quality was compared with a circular mapping catheter to assess pulmonary vein isolation and esophageal temperature monitoring was used. In the streamline phase (n=166), a single-catheter approach was implemented. Postprocedural cerebral magnetic resonance imaging was performed in 53 patients. In 52 patients, esophageal endoscopy was performed at day 1 after the procedure. Follow-up was performed using 72 hours Holter ECGs.

RESULTS

On a pulmonary vein basis, pulmonary vein isolation rate was 100% including a single shot isolation rate of 99.5%. The electrogram information of the pulsed field ablation catheter and the circular mapping catheter were 100% congruent. Neither esophageal temperature rises nor esophageal thermal injury were observed. Two minor strokes occurred, presumable due to air embolism during catheter exchanges through the large bore sheath (13.8 F ID). In the streamline phase, reduced procedure times (46±14 versus 38±13 minutes, P=0.004), no further strokes and a low incidence of silent cerebral injury (10/53 patients; 19%) were noted. During short-term follow-up, 17/191 patients (9%) had a atrial tachyarrhythmia recurrence.

CONCLUSIONS

The pulsed field ablation device allows for simple and safe simple single shot pulmonary vein isolation using standard sedation protocols. Procedural speed and efficacy are remarkable and streamlining measures have added safety.

[Pulsed field ablation : The ablation technique of the future?]

The ablation of cardiac arrhythmias is now standard therapy in invasive electrophysiology with a focus on atrial fibrillation due to its high prevalence. Thermal energy sources such as radiofrequency or cryoablation are the most commonly used techniques to date. Due to limitations in terms of effectiveness and safety because of possible indiscriminate tissue destruction, ablation using pulsed field ablation (PFA) can be a safe and effective alternative to thermal ablation techniques. This is a nonthermal form of energy that creates effective myocardial lesions by means of irreversible electroporation by generating short, high-energy electrical impulses. Preliminary data show high effectiveness with a low complication rate. Myocardial tissue shows a high specificity while sparing surrounding structures such as the esophagus, the phrenic nerve and surrounding vascular structures. Therefore, irreversible electroporation is a very promising technique and has the potential to become the perfect form of energy for many catheter ablations and especially for pulmonary vein isolation. In this article we provide an overview of the current status of PFA as well as an outlook on future fields of treatment.