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.
OBJECTIVE: 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.
CONCLUSIONS: 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.

BACKGROUND: Pulsed field ablation (PFA), a novel treatment for atrial fibrillation (AF), has yet to be evaluated in a Japanese cohort.
METHODS: In this sub-analysis of the PULSED AF trial, 12-month outcomes of paroxysmal AF (PAF) and persistent AF (PsAF) patients treated with PFA in four Japan centers were assessed. After a 90-day blanking period, primary efficacy was determined via freedom from a composite endpoint of acute procedural failure, arrhythmia recurrence, or antiarrhythmic drug escalation over 1 year. Patient improvement was evaluated via two quality of life (QoL) surveys (AFEQT and EQ-5D) at baseline and 12 months.
RESULTS: The analysis included 32 patients, 16 PAF and 16 PsAF, with PAF patients averaging 61.1 ± 10.6 years and PsAF patients averaging 62.8 ± 11.5 years of age. Females made up 31% of PAF and 25% of PsAF cohorts. Acute pulmonary vein isolation was achieved in 100% of both cohorts. The primary efficacy success rate at 12 months was 75.0% for PAF and 56.3% for PsAF patients. No primary safety events occurred. The mean AFEQT score significantly increased for both PAF (25.9 points, p < 0.0001) and PsAF (13.2 points, p = 0.0002) patients, while the EQ-5D-5L score improved significantly for PAF (0.12 points, p = 0.048) patients but not for PsAF (0.04 points, p = 0.08) patients.
CONCLUSIONS: Similar to outcomes in the global cohort, ablation with the PulseSelect™ PFA catheter was efficient, effective, and safe in a Japanese population, resulting in improved QoL for PAF and PsAF patients.
BACKGROUND: ClinicalTrials.gov Identifier: NCT04198701.

Pulsed field ablation (PFA) is a nonthermal energy source used for cardiac ablation procedures. Cell death during PFA occurs via electroporation: ultrarapid (micro- to nanosecond) electrical pulses are applied to destabilize cell membranes causing irreversible pores. PFA leads to preferential ablation of myocardiocytes, sparing adjacent tissue like the esophagus or phrenic nerve. Preliminary clinical studies show high efficacy and a good safety profile in atrial fibrillation patients undergoing pulmonary vein isolation. The question remains, however, whether this new technology will replace well-known and established thermal energy sources like radiofrequency current or cryoablation within the next 5 years.
UNASSIGNED: Die Pulsed-Field-Ablation (PFA) ist eine nichtthermische Energieform, bei deren Anwendung durch kurze Pulse hoher Spannung mittels des Prinzips der Elektroporation Gewebe abladiert wird. Es besteht eine gewisse Selektivität der PFA für Kardiomyozyten, so dass das umgebende Gewebe wie der N. phrenicus oder auch der Ösophagus geschont wird. In ersten klinischen Untersuchungen zeigt sich eine hohe Effektivität und Sicherheit bei der Pulmonalvenenisolation (PVI) zur Behandlung von Vorhofflimmern. Die Frage ist, ob diese neue Energieform der Ablation die thermischen Verfahren wie Hochfrequenzstrom und Kryoablation in 5 Jahren ersetzten wird.

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

UNASSIGNED: Pulsed field ablation (PFA) is increasingly used in clinical practice for the treatment of atrial fibrillation. While the susceptibility of erythrocytes to electroporation is well established, the effect of cardiac PFA technologies on hemolysis has remained underreported. The aim of this study was to investigate the incidence, severity, and clinical impact of PFA-induced hemolysis.
UNASSIGNED: We included n=145 patients undergoing atrial fibrillation catheter ablation with a pentaspline PFA catheter (biphasic, bipolar pulses of 2 kV) and n=70 patients receiving radiofrequency ablation (40-90 W) at 4 high-volume European centers. The lesion set comprised pulmonary vein isolation for paroxysmal atrial fibrillation and pulmonary vein isolation±additional lesions for persistent atrial fibrillation. Hemolysis and renal function biomarkers were analyzed in blood samples at baseline, at the end of ablation, and 24 hours after the procedure.
UNASSIGNED: Baseline characteristics were well balanced between groups (overall mean, 65.7±9.4 years; 69.3% male). The ablation procedures comprised a mean of 61.6±27.4 PFA deliveries and 26.3±15.0 minute RF duration. Hemolysis was detected in 94.3% versus 6.8% of patients after PFA versus radiofrequency ablation (P<0.001): PFA was associated with significantly lower haptoglobin levels (0.5±0.4 versus 1.0±0.4 g/L), while free plasma hemoglobin (592.8±330.6 versus 147.8±183.0 mg/L), bilirubin (21.3±11.3 versus 14.8±8.8 µmol/L), and LDH (lactate dehydrogenase, 352.7±115.7 versus 253.2±56.5 U/L) were significantly higher after PFA versus radiofrequency ablation (all P<0.001). Hemolysis correlated with the number of PFA deliveries (r=0.62 [95% CI, 0.33-0.80]; P<0.001), with the highest severity occurring ≥54 PFA deliveries. After PFA, hemoglobinuria occurred in 36.4%, while creatinine increase was higher in patients with baseline glomerular filtration rate <50 mL/min versus baseline glomerular filtration rate >50 mL/min (Δcrea, 27.0±103.1 versus -0.2±12.1 µmol/L; P=0.010).
UNASSIGNED: Intravascular hemolysis is a frequent finding after PFA and increases with the number of PFA deliveries. Until the clinical impact of PFA-associated hemolysis is fully elucidated, a careful titration of PFA deliveries during the ablation procedure is warranted.

Exposing cells to intense and brief electric field pulses can modulate cell permeability, a phenomenon termed electroporation. When applied in medical treatments of diseases like cancer and cardiac arrhythmias, depending on level of cellular destruction, it is also referred to as irreversible electroporation (IRE) or Pulsed Field Ablation (PFA). For ablation device testing, several pulse parameters need to be characterized in a comprehensive manner to assess lesion boundary and efficacy. Overly aggressive voltages and application numbers increase animal burden. The potato tuber is a widely used initial model for the early testing of electroporation. The aim of this study is to characterize and refine bench testing for the ablation outcomes of PFA in this simplistic vegetal model. For in vitro assays, several pulse parameters like voltage, duration, and frequency were modulated to study effects not only on 2D ablation area but also 3D depth and volume. As PFA is a relatively new technology with minimal thermal effects, we also measured temperature changes before, during, and after ablation. Data from experiments were supplemented with in silico modeling to examine E-field distribution. We have estimated the irreversible electroporation threshold in Solanum Tuberosum to be at 240 V/cm. This bench testing platform can screen several pulse recipes at early stages of PFA device development in a rapid and high-throughput manner before proceeding to laborious trials for IRE medical devices.

BACKGROUND: Due to its unique features, pulsed field ablation (PFA) could potentially overcome some limitations of current radiofrequency (RF) ventricular tachycardia (VT) ablation. However, data on the use of PFA in this setting are currently scarce.
METHODS: Two patients with ischemic cardiomyopathy and previously failed RF VT ablations were treated with PFA.
RESULTS: A total of 18 bipolar applications (case1) and seven bipolar applications (case2) were delivered to the infero-lateral and infero-septal areas (case1) and to the apical lateral left ventricular (LV) wall (case2), placing the catheter adjacent to the LV wall in the flower configuration. A rapid cessation of VT and restoration of sinus rhythm were observed during PFA delivery in both cases. Further applications were delivered to achieve complete elimination of late potentials. In case 1, during the in-hospital stay, ECG monitoring did not show VT recurrences. Six-month follow-up was uneventful, with no VT recurrences at ICD interrogation. In case 2, due to postdischarge VT recurrences, a second RF procedure was scheduled 1 month later. The voltage map performed in sinus rhythm showed a low-voltage zone located at the anterolateral wall, near the previous ablation site. Numerous late potentials were recorded. At the 6-month follow-up, no further VT recurrences were documented after RF redo ablation.
CONCLUSIONS: While the speed of application and potential transmural effect can facilitate the ablation of large diseased endocardial areas, early loss of contact due to difficult pentaspline catheter manipulation in the LV could lead to insufficient contact force and, consequently, inadequate energy penetration.

BACKGROUND: Pulsed field ablation (PFA) is an emerging non-thermal ablation method. The primary challenge is the control of multiple parameters in PFA, as the interplay of these parameters remains unclear in terms of ensuring effective and safe tissue ablation.
OBJECTIVE: This study employs the response surface method (RSM) to explore the interactions between various PFA parameters and ablation outcomes, and seeks to enhance the efficacy and safety of PFA.
METHODS: In vivo experiments were conducted using rabbit liver for varying PFA parameters: pulse amplitude (PA), pulse interval (PI), number of pulse trains (NT), and number of pulses in a pulse train (NP). Ablation outcomes assessed included three ablation sizes, surface temperature, and muscle contraction strength. Additionally, histological analysis was performed on the ablated tissue. We analyzed the relationship between PFA parameters and ablation outcomes, and results were then compared with those from a simulation using an electric-thermal coupling PFA finite element model.
RESULTS: A linear relationship between ablation outcomes and PFA parameters was established. PA and NT exhibited extremely significant (P < 0.0001) and significant effects (P < 0.05) on all ablation outcomes, respectively. NP showed an extremely significant impact (P < 0.0001) on surface temperature and muscle contraction strength, while PI significantly influenced (P < 0.05) muscle contraction strength alone. Histological analysis revealed that PFA produces controlled, well-defined areas of liver tissue necrosis. Surface temperature results from simulations and experiments were highly consistent (R2 > 0.97).
CONCLUSIONS: This study clarifies the relationship between various PFA parameters and ablation outcomes, and aims to improve the efficacy and safety of PFA.

BACKGROUND: Pulsed-field ablation (PFA) and fluoroless ablation (FA) are emerging techniques in contemporary in electrophysiology. With widespread use of 3D electroanatomic mapping systems and advanced intracardiac echo (ICE) imaging, fluoroless ablation has become more widely adopted. However, with the importance of tissue contact for lesion durability, initial PFA has been used with fluoroscopic guidance, but both ICE and electroanatomic mapping make fluoroless PFA feasible. The objective of this study is to demonstrate that PFA can be done safely and effectively without fluoroscopy.
METHODS: At a single center, consecutive patients undergoing ablation with a pentaspline PFA catheter using a fluoroless approach are described. The standard 3D anatomic map settings were adjusted with changes in interior and exterior projection, respiratory compensation, and interpolation. In addition, projection map lesions were used to confirm adequate circumferential ablation lesions. ICE was used extensively for wire guidance and evaluation of contact with tissue.
RESULTS: Beginning on March 15, 2024, 50 consecutive subjects (19 female/31 male) aged 68.0 (± 13.7) underwent PFA ablation. The average CHA2DS2-VA2Sc score was 3.0 (± 1.9). The average LVEF was 57.3% (± 10.0) and the average LA size was 3.9 cm (± 1.2). Projection lesions were placed with every application of PFA. An average of 41.7 (± 8.5) PFA applications were placed. In 100% (50/50) of subjects, acute isolation of the pulmonary veins was achieved. Eighteen subjects also underwent concomitant posterior wall isolation and in 100% of these subjects, posterior isolation was achieved. There were zero complications in this cohort. In 50/50 subjects (100%), fluoroscopy was not used. In comparison to the control cohort, the LA dwell time of the ablation catheter was similar (p = 0.34).
CONCLUSIONS: In comparison to the traditional PFA with fluoroscopy, this proof-of-concept study shows fluoroless PFA ablation can be performed safely and with similar acute success rates as with use of fluoroscopy.

BACKGROUND: In vitro models to evaluate cardiac pulsed field ablation (PFA) have not been well established. We sought to create a standardized vegetable model and staining protocol for assessing unipolar PFA using a surface electrode.
METHODS: We exposed potato slabs to unipolar PFA in a saline bath using a 3.5 mm electrode catheter and grounding pad connected to a custom-built high-voltage generator. Lesions were clearly visualized after staining with 2,3,5-triphenyltetrazolium chloride (TTC) using a timed protocol to reveal a necrotic center and a periphery of electroporated cells with intact mitochondria.
RESULTS: Lesion volume increased linearly with increasing voltage and logarithmically with repetitive PFA applications.
CONCLUSIONS: The findings observed in this vegetable model using a TTC staining protocol are consistent with findings observed with cardiomyocytes.