Energy Source For Ablation Research Articles

Prediction of major intravascular hemolysis during pulsed electric field ablation of atrial fibrillation using a pentaspline catheter.

Pulsed electric field (PEF) has emerged as a promising energy source for catheter ablation of atrial fibrillation (AF). However, data regarding the in-vivo effect of PEF energy on erythrocytes during AF ablation procedures are scarce. This study aimed to quantify the impact of PEF energy on erythrocyte damage during AF ablation by assessing specific hemolytic biomarkers. A total of 60 patients (age: 68 years, males: 72%, serum creatinine: 91 µmol/L) with AF underwent catheter ablation of AF using PEF energy delivered by a multipolar pentaspline Farawave catheter (Farapulse, Boston Scientific, Inc.). Ablation beyond pulmonary vein isolation was performed at the operator's discretion. Peripheral venous blood was sampled for assessing the plasma levels of free hemoglobin (fHb), direct (conjugated) bilirubin, lactate dehydrogenase (LDH), and creatinine before, immediately after the ablation, and on the next day. Following the PEF ablation with duration of [median (interquartile range)] 75 (58, 95) min, with 74 (52, 92) applications and PVI only in 27% of patients, fHb, LDH, and direct bilirubin significantly increased, from 40 (18, 65) to 493 (327, 848) mg/L, from 3.1 (2.6, 3.6) to 6.8 (5.0, 7.9) µkat/L, and from 12 (9, 17) to 28 (16, 44) µmol/L, respectively (all p < .0001). A strong linear correlation was found between the peak fHb and the number of PEF applications (R = 0.81, p < .001). The major hemolysis (defined as fHb >500 mg/L) was predicted by the number of PEF applications with the corresponding area under the receiver operating characteristic curve of 0.934. The optimum cut-off value of >74 PEF applications predicted the major hemolysis with 89% sensitivity and 87% specificity. Catheter ablation of AF using PEF energy delivered from a pentaspline catheter is associated with significant intravascular hemolysis. More than 74 PEF applications frequently resulted in major hemolysis. However, the critical amount of PEF energy that may cause kidney injury in susceptible patients remains to be investigated.

Pulsed-field ablation-is it the only energy source for ablation in the future? : Pro/Contra

Pulsed field ablation (PFA) is anonthermal 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 agood 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 5years.

Effect of Ablation Energy Source on Outcomes of Slow Pathway Modification for AVNRT in Children

BackgroundSelection of radiofrequency ablation (RF) or cryoablation (Cryo) for atrioventricular nodal re-entrant tachycardia (AVNRT) in children remains controversial due to a lack of contemporary comparison studies in this population. ObjectivesThis study sought to compare outcomes of RF and Cryo for AVNRT in the pediatric population. MethodsAVNRT ablation outcomes were retrospectively analyzed utilizing the National Cardiovascular Data Registry IMPACT (Improving Pediatric and Adult Congenital Treatment) Registry from April 2016 to March 2019. Data from subjects 1 to 21 years of age undergoing elective first-time slow pathway (SP) modification for AVNRT were included. Exclusion criteria included <1 year of age, congenital heart disease, and >1 ablation target. Cases were analyzed by ablation energy: 1) RF only; 2) Cryo only; 3) radiofrequency ablation switching to cryoablation (RF→Cryo); and 4) cryoablation switching to radiofrequency ablation (Cryo→RF). The primary outcome was acute ablation failure. Secondary outcomes included in-hospital adverse events. ResultsAmong 2,448 patients (mean age 13.6 ± 3.4 years, 60% female), RF only was employed in 43% (n = 1,046), Cryo only in 49% (n = 1,201), RF→Cryo in 6% (n = 135), and Cryo→RF in 66 (3%). Acute ablation failure occurred in 1.3% (n = 33), with no difference by energy source (1% in RF only, 1.5% in Cryo only, 1.5% in RF→Cryo, 3% in Cryo→RF; P = 0.5). Atrioventricular (AV) block requiring permanent pacemaker did not occur in any group; transient AV block occurred in 0.4% of the cohort, with no difference by group. ConclusionsIn this largest pediatric study of AVNRT ablation, RF and Cryo demonstrated comparable high acute success and rare documentation of AV block that did not result in temporary or permanent pacing. Longitudinal data are important for further comparison of these modalities with regard to recurrence risk and late complications.

Comparison between cryotherapy and radiofrequency energy sources for parahisian accessory pathway percutaneous ablation.

Catheter ablation of parahisian accessory pathways (PHAP) are challenging due to their proximity to the normal conduction system. Retrospective studies suggest that cryoablation has a better safety profile but a higher recurrence rate when compared to radiofrequency ablation (RFCA). The objective of this study was to compare the results of parahisian AP ablation performed by electrophysiologists with experience in both technologies. Prospective single-center, non-blinded and 1:1 model was used. Patients included had parahisian AP confirmed by an electrophysiological study and referred for radiofrequency or cryotherapy ablation according to current guidelines, under fluoroscopic guidance. No electroanatomic mapping was used. A total of 30 patients (mean age of 25±9.4 years; 90% male) were enrolled between Oct/2018 to Feb/2020. Acute success rate between RFCA and CRYO were similar (93% vs. 87%, p = 0.54). A nonsignificant reduction in short-term recurrence rate for RFCA (14% vs. 30%, p = 0.3) and mechanical trauma (6% vs. 20%; p = 0.28) was observed. Long-term recurrence rate and event-free survival time were similar in both groups after 1-year follow-up (p = 0.286). No persistent complete AV block or conduction disturbance was also observed. Considering the limitation of a small sample size and the lack of use of electroanatomic mapping for RFCA, the efficacy and safety profile of parahisian AP ablation with RFCA was not different from CRYO, when performed by experienced electrophysiologists. No cases of permanent complete AV block were reported with either energy modalities.

Biochemical markers of neuro-myocardial damage after pulmonary vein isolation: the effect of different energy sources

Abstract Background Pulmonary vein isolation (PVI) by thermal energy, both radiofrequency (RF) and cryoenergy(Cryo), is associated with a significant release of myocardial and collateral neural injury markers. Damage to periatrial ganglionated plexi also results in a substantial change in cardiac autonomic regulations. On the contrary, pulsed electric field (PEF) energy tends to spare cardiac neural tissue. Purpose To quantify the impact of different ablation energy sources that are used for PVI on neuro-myocardial damage by the assessment of specific biomarkers. Methods A study enrolled 85 patients with paroxysmal atrial fibrillation who underwent PVI (age: 61 ± 12 years, 74% males). In 23 patients, RF energy was delivered by the irrigated-tip catheter, while 30 patients were ablated using a second-generation cryoballoon catheter. In 32 patients, PVI was performed using a multipolar pentaspline catheter and PEF energy. Peripheral venous blood samples for assessing the plasmatic levels of S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), high-sensitivity troponin I and T (hsTnI and hsTnT) were obtained before, immediately after the PVI, and the next day (usually 18-24 hours after the procedure). Study groups were compared regarding absolute biomarker levels and hsTnT/S100B ratio (a surrogate of cardioselectivity). Results Following successful PVI, a significant increase in plasma levels of all biomarkers was observed: DhsTnT = 1040±434 ng/L, 1731±830 ng/L and 1010±397 ng/L; DhsTnI = 1504±918 ng/L, 16464±11911 ng/L and 10789±7589 ng/L; DS100B: 0.04±0.02 mg/L, 0.03±0.04 mg/L and 0.14±0.08 mg/L; DNSE: 34±72 ng/mL, 27±53 ng/mL and 45±52 ng/mL (all with P &amp;lt;0.001) for RF, PEF and Cryo groups, respectively. A direct comparison of maximal biomarker levels between study groups is depicted in the Figure. The hsTnT/S100B ratio was 23±14, 12±6, and 6±3 in PEF, RF, and Cryo groups, respectively (ANOVA P &amp;lt;0.01), indicating that PEF was 1.9-times and 3.8-times more cardioselective than RF and Cryo, respectively. Following the PVI, the heart rate accelerated by 2±8, 13±14, and 9±11 bpm in the PEF, RF, and Cryo groups, respectively. No correlation was observed between S100B release and HR acceleration (R = 0.07, P = 0.55). Conclusion Compared to thermal energy sources, PEF energy induces more specific damage to cardiomyocytes than cardiac nerves. There was no correlation between S100B release and HR acceleration.

Feasibility and efficacy of single-shot PFA technology for redo procedures after a previous atrial fibrillation ablation procedure

Abstract Introduction Despite significant technological advancements and a better understanding of atrial tachyarrhythmia pathophysiology, a non-negligible percentage of atrial fibrillation (AF) patients undergoing catheter ablation experiences arrhythmia relapse. Repeat procedures have been traditionally performed via thermal energy systems, which carry a certain risk of collateral damage to adjacent tissues. Pulsed Field Ablation (PFA) has emerged as an alternative non-thermal energy source for cardiac ablation. The main advantage is its selectivity to cardiac tissue. FarapulseTM is the first PFA technology to have received regulatory approval and includes a pentaspline PFA catheter. Although designed for pulmonary vein isolation, its use for extrapulmonary vein site ablation has been previously documented. Purpose To evaluate the feasibility and efficacy of the pentaspline FarawaveTM for redo procedures. Methods Patients referred for a redo procedure using FarapulseTM system were enrolled in 3 high-volume European centers. A workflow (Figure 1.A) was established based on rhythm at presentation (Group 1: sinus rhythm; Group 2: AFL; Group 3: AF). Results A total of 117 patients were included (64 in Group 1, 18 in Group 2, and 35 in Group 3). The mean number of previous procedures was 1.26, and 23 patients (19.66%) had already undergone ≥2 procedures. Previous ablation targets included PVI, either alone (46.15%) or in combination with other targets, including posterior mitral line (39.32%), posterior wall (6.84%), or anterior mitral line (2.56%). Electroanatomical mapping (EAM) was adopted in 15.38% of the cases. Specifically, in 27.78% (n=5) of group 2, 15.63% (n=10) of group 1 and 8.57% (n= 3) of group 3 cases. Additional focal radiofrequency ablation was required in 4 patients for CTI line ablation. Lesion sets are depicted in Figure 2. Mean procedural and LA dwelling time were 95.2 ± 38.0 and 50.7 ± 36.7 minutes, respectively. There was a total of one major complication (intracranial haemorrhage) and 5 minor complications (two vascular site related, and three reversible ST segment changes, related to applications on the mitral annulus area). A total of 100 patients completed at least 3 months of follow-up (FU), with a median FU time was 7.55 months (IQR 5.18 – 11.85). The total number of recurrences was 20, including 2 during the blanking period. Survival function (excluding blanking period) was 88.6 (95% CI 79.7 – 93.8) at 6 months and 80.0% (95% CI 67.3 – 88.3) 12 months. Atrial arrhythmia free-survival was higher in patients presenting in sinus rhythm, compared to the other two groups (p = 0.0135), as displayed in Figure 1.B. Conclusion The proposed stepwise approach to repeat AF ablation procedures based on the use of the single-shot PFA system (with or without EAM) was feasible, safe, fast and effective at one year follow-up.Flow chart and Kaplan Meier curveLesion sets

Real-world multicenter registry on a novel focal lattice tip catheter toggling between pulsed electric field and radiofrequency for atrial tachyarrhythmia ablation

Abstract Background Pulsed field ablation (PFA) has emerged as a novel non-thermal energy source for cardiac tissue ablation. A novel focal 9mm lattice tip catheter, namely Sphere-9 (Affera Inc), has recently received regulatory approval; the technology is part of a technology that allows the delivery of either pulsed electric field or radiofrequency energy and incorporates a proprietary 3D electroanatomical mapping system. Purpose To describe the first real-world, multicenter experience with the AfferaTM system. Methods Consecutive AF patients undergoing first-time or redo atrial tachyarrhythmia ablation with the AfferaTM system in two different centres between August and November 2023 were prospectively enrolled. PFA was always used to ablate the posterior left atrium, whereas anterior applications were performed using either radiofrequency energy (RF/PF strategy) or PFA (PF/PF strategy) based on operator's discretion. Data on first-pass pulmonary vein isolation (PVI) and posterior wall isolation (PWI), as well as success rate of extrapulmonary ablation were reported. Primary safety endpoint included any technology-related periprocedural complications. Results 46 patients (mean age: 67±10; 41.3% males, 60.8% non-paroxysmal AF) were included. 5 (10.8%) patients were in atrial flutter (AFlu) at the beginning of the procedure, whereas AF was the rhythm at presentation in 19 (41.3%) others. First-time PVI was performed in 37 (80.4%) patients, 68.4% of whom received concomitant PWI. PVI was performed with PFA-only in 27% of them. First-pass isolation was achieved in 97.3% and 100% of PVI and PWI cases, respectively. Additional lesions included an anterior or posterior mitral line (6 and 15 patients), CTI (4 patients) or substrate ablation in 3 patients. Evidence of first-pass line block was documented in 96.4% of patients. The remaining 9 (19.6%) patients had already undergone a previous ablation; remapping showed 27.7% of PVs requiring reisolation. PWI was performed in 88.9% of them, for the first time (75%) or due to reconnection (25%). Additional lesions included an anterior or posterior mitral line (3 and 3 patients) or CTI in 2 patients. Evidence of first-pass line block was documented in 100% of patients. In 3 AFlu patients, the arrhythmia was mapped and termination was achieved while performing an AML (2 patients) and CTI (1 patient). Procedural duration was 96.5±15.6 min for first time and 97.8±12.6 min for redo procedures. Mean left atrial dwelling and fluoroscopy times were 75.4±17.6 min and 7.36±2.1 min, respectively. No technology-related complications were documented. Conclusions AF ablation with the focal 9-mm lattice tip catheter Sphere-9 confirmed high efficacy and safety in a real-world population.

Repeat pulmonary vein isolation and anterior line ablation using a novel point-by-point pulsed-field ablation system

BackgroundPulsed-field ablation (PFA) is a nonthermal energy source for ablation of cardiac arrhythmias. This study investigated the prospective outcomes of a novel PFA generator in conjunction with a commercially available, contact force-sensing, focal ablation catheter. ObjectiveThe purpose of this study was to assess the feasibility, safety, and lesion characteristics of point-by-point PFA in consecutive patients undergoing repeat ablation of atrial fibrillation (AF). MethodsThe study involved reisolation of pulmonary veins (PVs) with electrical reconnection and the creation of an anterior line (AL) in patients with anterior substrate or durable pulmonary vein isolation (PVI). ResultsIn 24 patients (46% female; mean age 67 ± 10 years; 67% persistent AF), successful reisolation of 27 of 27 reconnected PVs (100%) was performed. In 19 patients, AL ablation was performed, with bidirectional block in 16 (84%), median ablation time 26 [21, 33] minutes, and first-pass bidirectional block in 13 patients (68%). Acute AL reconduction occurred in 8 of 19 patients (42%). Among these 8 patients, a subsequent sustained block of the AL was achieved in 5 (63%). Ultra-high-density electroanatomic mapping revealed homogeneous but relatively large low-voltage areas in the ablated regions. Median procedural, left atrial dwell, and fluoroscopy times were 100 [90, 109] minutes, 83 [75, 98] minutes, and 10 [8, 13] minutes, respectively. No major or minor complications occurred. ConclusionThis study demonstrated feasibility, acute efficacy, and safety of point-by-point PFA for repeat PVI and AL ablation. Further studies are warranted to assess the long-term durability and comparison with established ablation methods.

Impact of pulsed field ablation on intraluminal esophageal temperature.

Atrio-esophageal fistula after esophageal thermal injury (ETI) is one of the most devastating complications of available energy sources for atrial fibrillation (AF) ablation. Pulsed field ablation (PFA) uses electroporation as a new energy source for catheter ablation with promising periprocedural safety advantages over existing methods due to its unique myocardial tissue sensitivity. In preclinical animal studies, a dose-dependent esophageal temperature rise has been reported. In the TESO-PFA registry intraluminal esophageal temperature (TESO) changes in a clinical setting are evaluated. Consecutive symptomatic AF patients (62 years, 67% male, 61% paroxysmal AF, CHA2 DS2 Vasc Score 2) underwent first-time PFA and were prospectively enrolled into our registry. Eight pulse trains (2 kV/2.5 s, bipolar, biphasic, x4 basket/flower configuration each) were delivered to each pulmonary vein (PV). Two extra pulse trains per PV in flower configuration were added for wide antral circumferential ablation. Continuous intraluminal esophageal temperature (TESO) was monitored with a 12-pole temperature probe. Median TESO change was statistically significant and increased by 0.8 ± 0.6°C, p < .001. A TESO increase ≥ 1°C was observed in 10/43 (23%) patients. The highest TESO measured was 40.3°C. The largest TESO difference (∆TESO) was 3.7°C. All patients remained asymptomatic considering possible ETI. No atrio-esophageal fistula was reported on follow-up. A small but significant intraluminal esophageal temperature rise can be observed in most patients during PFA. TESO rise over 40°C is rare. The clinical implications of the observed findings need to be further evaluated.

Pulsed field ablation for pulmonary vein isolation: Preclinical safety and effectiveness of a novel hexaspline ablation catheter.

Pulsed-field ablation (PFA) has emerged as a nonthermal energy source for cardiac ablation, with potential safety advantages over radiofrequency ablation (RFA) and cryoballoon ablation. To report the preclinical results of a novel hexaspline PFA catheter for pulmonary vein isolation (PVI), and to verify the influence of PFA on esophagus by comparing with RFA. This study included a total of 15 canines for the efficacy and safety study and four swine for the esophageal safety study. The 15 canines were divided into an acute cohort (n = 3), a 30-day follow-up cohort (n = 5) and a 90-day follow-up cohort (n = 7), PVI was performed with the novel hexaspline PFA ablation catheter. In the esophageal safety study, four swine were divided into PFA cohort (n = 2) and RFA cohort (n = 2), esophageal injury swine model was adopted, the esophagus was intubated with an esophageal balloon retractor, under fluoroscopy, the DV8 device was inflated with a mixture of saline and contrast and rotated to displace the esophagus rightward and anteriorly toward the ablation catheter in the inferior vena cava (IVC) and right inferior pulmonary vein (PV). Nine PFA applications were delivered at four locations on IVC and two locations on theright inferior PV in thePFA cohort, six RFA applications were delivered at each location in the RFA group. Histopathological analysis of all PVs, esophagus, IVC, and the adjacent lungs was performed. Acute PV isolation was achieved in all 15 canines (100%), with energy delivery times of less than 3 min/animal. In the 30 and 90 days group, the overall success rates were 88.9% and 88.5% per PVs, respectively. Two right superior pulmonary veins (RSPVs) in the 30-day group, two RSPVs and one left superior PV in the 90-day group with recovered potentials. At follow-up, gross pathological examination revealed the lesions around the PVs were continuous and transmural. Masson's trichrome staining revealed the myocardial cells in the PVs became fibrotic, but small arteries and nervous tissue were preserved. Results of swine esophageal injury model revealed the esophageal luminal surface was smooth and without evidence for esophageal injury in the PFA group, whereas obvious ulceration was detected on the esophagus tunica mucosa in the RFA group. In the chronic canine study, PFA-based PVI were safe and effective with demonstrable sparing of nerves and venous tissue. Compared with RFA, there was also good evidence for safety of PFA, avoiding PV stenosis and esophageal injury. This preclinical study provided the scientific basis for the first-in-human endocardial PFA studies.

Simulation Results and Analysis of Electric Field Distribution in Myocardial Tissue under Circular Electrode Electric Pulse Ablation

As a new energy source for atrial fibrillation ablation, electric pulse ablation has higher tissue selectivity and biosafety, so it has a great application prospect. At present, there is very limited research on multi-electrode simulated ablation of histological electrical pulse. In this study, a circular multi-electrode ablation model of pulmonary vein will be built on COMSOL5.5 platform for simulation research. The results show that when the voltage amplitude reaches about 900 V, it can make some positions achieve transmural ablation, and the depth of continuous ablation area formed can reach 3 mm when the voltage amplitude reaches 1 200 V. When the distance between catheter electrode and myocardial tissue is increased to 2 mm, a voltage of at least 2 000 V is required to make the depth of continuous ablation area reach 3 mm. Through the simulation of electric pulse ablation with ring electrode, the research results of this project can provide reference for the voltage selection in the clinical application of electric pulse ablation.

Feasibility and proof of concept of a proprietary non-contact ablation system with low intensity collimated ultrasound

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Heailum Medical Inc. Background Utilization of collimated acoustic energy transition as an ablation energy source has the advantage of propagation through blood with negligible absorption. This allows delivery of non-contact, directional and precise ablation lesions to cardiac tissue. In addition, with dual mode ultrasound technology real-time monitoring of the tissue is possible during ablation. Aim To evaluate a proprietary ultrasound-based ablation system in swine and define the characteristics of the isolated ablation lesions and lines performed in-vivo. Methods In female large white swines, bilateral thigh muscle prep ablations were performed using different time and energy ablation parameters while tip to tissue distance measured with the imaging B-mode and set to 10mm. Lesions were analysed for maximal depth and width. Additional assessment for contiguous linear ablation was performed in the thigh muscle, SVC and within the coronary sinus with the transducer rotated to the endocardial direction. Tissue was fixed in formalin and gross pathological examination with lesion measurement was performed. Results 36 distinct ablation lesions were performed in the thigh prep model. No steam pops were observed for any of the lesions. Mean necrotic lesion depth was 5.35 ± 1.5mm, with increased time with greater influence on dimensions compared to small changes in energy delivered (Figure 1). Reversible damage influenced additional 29% of tissue depth, while 55% additional tissue width was reversible. Linear ablation performed at 2.5mm inter-lesion distance showed contiguous lines, with transmural effect in both SVC and coronary sinus. Conclusions A novel ultrasound based catheter ablation has the ability for non-contact effective ablation in cardiac tissue with directional and tailored energy selection to achieve transmural atrial ablation. Additional in-vivo experimentation will allow refinement of this tool for both isolated lesions and linear ablation while enabling tissue visualization.

Safety and Effectiveness of Pulsed Field Ablation to Treat Atrial Fibrillation: One-Year Outcomes From the MANIFEST-PF Registry.

Pulsed field ablation is a novel nonthermal cardiac ablation modality using ultra-rapid electrical pulses to cause cell death by a mechanism of irreversible electroporation. Unlike the traditional ablation energy sources, pulsed field ablation has demonstrated significant preferentiality to myocardial tissue ablation, and thus avoids certain thermally mediated complications. However, its safety and effectiveness remain unknown in usual clinical care. MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a retrospective, multinational, patient-level registry wherein patients at each center were prospectively included in their respective center registries. The registry included all patients undergoing postapproval treatment with a multielectrode 5-spline pulsed field ablation catheter to treat atrial fibrillation (AF) between March 1, 2021, and May 30, 2022. The primary effectiveness outcome was freedom from clinical documented atrial arrhythmia (AF/atrial flutter/atrial tachycardia) of ≥30 seconds on the basis of electrocardiographic data after a 3-month blanking period (on or off antiarrhythmic drugs). Safety outcomes included the composite of acute (<7 days postprocedure) and latent (>7 days) major adverse events. At 24 European centers (77 operators) pulsed field ablation was performed in 1568 patients with AF: age 64.5±11.5 years, female 35%, paroxysmal/persistent AF 65%/32%, CHA2DS2-VASc 2.2±1.6, median left ventricular ejection fraction 60%, and left atrial diameter 42 mm. Pulmonary vein isolation was achieved in 99.2% of patients. After a median (interquartile range) follow-up of 367 (289-421) days, the 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was 78.1% (95% CI, 76.0%-80.0%); clinical effectiveness was more common in patients with paroxysmal AF versus persistent AF (81.6% versus 71.5%; P=0.001). Acute major adverse events occurred in 1.9% of patients. In this large observational registry of the postapproval clinical use of pulsed field technology to treat AF, catheter ablation using pulsed field energy was clinically effective in 78% of patients with AF.

PE-452787-3 INITIAL EXPERIENCE OF PULSED FIELD ABLATION OF ATRIAL FIBRILLATION AND ATRIAL TACHYCARDIA IN ADULT PATIENTS WITH CONGENITAL HEART DISEASE

Prevalence of atrial tachycardias (AT) and atrial fibrillation (AF) is increasing in adult patients with congenital heart disease (CHD) significantly contributing to morbidity. Catheter ablation of AT and AF in the adult CHD population is challenging and recurrence is significant. Pulsed field ablation (PFA) is a new, non-thermal energy source for catheter ablation of AF. Due to its inherent properties of creating effective ablation lesions without permanent affection of non-myocardial tissue, it is attractive for the use in the adult CHD population. To date, its use in the adult CHD population has not been reported. This study describes initial experience of PFA of AT and AF in adult CHD patients. Prospective enrollment of adult CHD patients with a history of recurrent AT/AF, who had prior radiofrequency (RFA)/cryoenergy (Cryo) ablation of AT/AF. A high-density map using a 3D mapping system (EnSite™ Precision; Abbott) in conjunction with a high-density catheter (Advisor™ HD Grid; Abbott) was performed prior and after PFA. PFA was performed using the FARAWAVE™ ablation catheter (Boston Scientific) and applying repeated 2 kV pulses (2.5 s each) to the respective substrate. Procedural success was defined as complete substrate ablation (residual atrial electrograms < 0.05 mV on voltage map). Four adult CHD patients with recurrent AT/AF despite repeated previous RFA/cryoablation were enrolled. 2/4 had interrupted inferior V. cava and a transhepatic access was used to get access to the left atrium. PFA of all pulmonary vein ostia and the left atrial posterior wall was performed in 3 subjects. Additional PFA of a septal low voltage area was achieved in one of these patients. In the fourth patient with Ebstein’s anomaly, PFA of the cavotricuspid isthmus (CTI) and of a conduction gap within the crista terminalis was performed. Complete procedural success was achieved in all patients. Transient, fully reversible spasm of the right coronary artery without ECG changes occurred after PFA within the CTI. No recurrence of AT/AF was observed during follow-up of 5 months. Herein, we report for the first time the use of PFA in adult CHD patients with recurrent AT/AF. PFA turned out to be effective and generally safe. When using it in proximity to the coronary arteries, one must be aware of reversible coronary artery spasm. PFA might be a valuable tool to improve mid- and long-term outcome of AT/AF ablation in the adult CHD population.

AB-452672-4 POINT-BY-POINT PULSED FIELD ABLATION USING A MULTIMODALITY GENERATOR: COMPARISON WITH RADIOFREQUENCY ABLATION IN REMAPPED CHRONIC SWINE HEARTS.

In recent years, Pulsed Field Ablation (PFA) has emerged as a novel non thermal energy source for ablation. To compare lesion durability and collateral damage between unipolar/biphasic PFA and RF delivered through a contact-force sensing catheter both in a point-by-point fashion. A 4 arm pre-clinical study (n=12 swine) was designed with the multimodality generator TRUPULSE™ 2. PFA was delivered with nominal dose (12 pulses) in Group 1 whereas a high PFA dose (24 pulses) was used to evaluate energy safety in Group 2. RF arms served as controls with energy deployed through multimodality (Group 3) or market available (Group 4) generators. A contact-force catheter was used to focally deliver PFA/RF at the right superior pulmonary vein (RSPV), left atrial posterior wall (LAPW) and Roof, mitral isthmus (MI), cavotricuspid Isthmus (CTI), and RA posterior wall (RAPW). Average contact force was 12.7±3.7g. Animals were remapped at immediate post and 28 days post ablation. All animals were euthanized at 28 days and gross necropsy and histology followed. Acute RSPV isolation was achieved in all animals (Figure 1). At 28 days, remapping showed that RSPV isolation was maintained in all but one animal (Group 1) showing an electrical gap confirmed on histology. RAPW, CTI, MI (with exception of 2 animals, 1 in Group 2 and 1 in Group 3), and LAPW were maintained per histology as well. Differently from RF, both PFA arms had essentially similar histopathologic effect showing benign mature scar tissue repair with no necrosis nor inflammation (Figure 1). PFA applied to the RA lateral and posterior wall did elicit phrenic nerve response during ablation confirming ablations were done on the nerve. However, at 28 days remap, the nerve was stimulated and, in all animals, remained intact with no signs of damage on necropsy or histology. Representative samples were selected from the downstream/upstream organs including the brain, rete mirabile, heart, lungs, liver, esophagus, spleen, and kidneys, which showed no evidence of thrombo-embolic events. In swine models, point-by-point unipolar/biphasic PFA ablation showed durable PVI lesions acutely and at remapping without any sign of collateral damage after 28 days remap study. On histology, PFA lesions evolved with scar tissue without signs of necrosis nor inflammation. Further studies are needed to investigate the long-term safety and efficacy of this point-by-point PFA contact force sensing catheter.

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.

Efficacy, Safety and Feasibility of Superior Vena Cava Isolation in Patients Undergoing Atrial Fibrillation Catheter Ablation: An Up-to-Date Review.

Pulmonary vein isolation (PVI) is the cornerstone in atrial fibrillation (AF) ablation; yet, the role of arrhythmogenic superior vena cava (SVC) is increasingly recognized and different ablation strategies have been employed in this context. SVC can act as a trigger or perpetuator of AF, and its significance might be more pronounced in patients undergoing repeated ablation. Several cohorts have examined efficacy, safety and feasibility of SVC isolation (SVCI) among AF patients. The majority of these studies explored as-needed SVCI during index PVI, and only a minority of them included repeated ablation subjects and non-radiofrequency energy sources. Studies of heterogeneous design and intent have explored both empiric and as-needed SVCI on top of PVI and reported inconclusive results. These studies have largely failed to demonstrate any clinical benefit in terms of arrhythmia recurrence, although safety and feasibility are undisputable. Mixed population demographics, small number of enrollees and short follow-up are the main limitations. Procedural and safety data are comparable between empiric SVCI and as-needed SVCI, and some studies suggested that empiric SVCI might be associated with reduced AF recurrences in paroxysmal AF patients. Currently, no study has compared different ablation energy sources in the setting of SVCI, and no randomized study has addressed as-needed SVCI on top of PVI. Furthermore, data regarding cryoablation are still in their infancy, and regarding SVCI in patients with cardiac devices more safety and feasibility data are needed. PVI non-responders, patients undergoing repeated ablation and patients with long SVC sleeves could be potential candidates for SVCI, especially via an empiric approach. Although many technical aspects remain unsettled, the major question to answer is which clinical phenotype of AF patients might benefit from SVCI?

Pulmonary vein isolation-induced vagal nerve injury and gastric motility disorders detected by electrogastrography: The side effects of pulmonary vein isolation in atrial fibrillation (SEPIA) study.

Safety of pulmonary vein isolation (PVI) has been established in clinical studies. However, despite prevention efforts the incidence of damage to (peri)-esophageal tissue has not decreased, and the pathophysiology is incompletely understood. Damage to vagal nerve branches may be involved in lesion progression to atrio-esophageal fistula. Using electrogastrography, we assessed the incidence of periesophageal vagal nerve injury (VNI) following atrial fibrillation ablation and its association with procedural parameters and endoscopic results. Patients were studied using electrogastrography, endoscopy, and endoscopic ultrasound before and after cryoballoon (CB) or radiofrequency (RF) PVI. The incidence of ablation-induced neuropathic pattern (indicating VNI) in pre- and postprocedural electrogastrography was assessed and correlated with endoscopic results and ablation data. Between February 2021 und January 2022, 85 patients (67 ± 10 years, 53% male) were included, 33 were treated with CB and 52 with RF (38 with moderate power moderate duration [25-30 W] and 14 with high power short duration [50 W]). Ablation-induced VNI was detected in 27/85 patients independent of the energy form. Patients with VNI more frequently had postprocedural endoscopically detected pathology (8% mucosal esophageal lesions, 36% periesophageal edema, 33% food retention) but there was incomplete overlap. Pre-existing esophagitis increased the likelihood of VNI. Ablation data and esophageal temperature data did not predict VNI. PVI-induced VNI is quite common and independent of ablation energy source. VNI is part of (peri)-esophageal damage and only partially overlaps with endoscopic findings. VNI-associated acidic reflux may be involved in the complex pathophysiology of esophageal lesion progression to fistula.

Efficacy and safety of novel pulsed field ablation (PFA) technique for atrial fibrillation: A systematic review and meta-analysis.

Pulse field ablation (PFA) has emerged as a safe alternative to other catheter ablation energy sources for patients. Although early results are encouraging, secondary data about outcomes are lacking. Herein, we aimed to assess the safety and efficacy of the novel technique. We searched PubMed, Ovid, Google Scholar, Web of Science, and Scopus databases and several major scientific conferences for studies reporting results regarding PFA. Sixteenstudies were included, reporting 485 patients with atrial fibrillation who underwent pulsed field operations. Patients averaged 60 years of age. The total duration of the procedure is 94 min. The average Fluoro procedure takes 17 min. Isolation of all pulmonary veins was 100% with a 95% confidence interval (CI)(p > 0.05). Overall, the recurrence rate of arrhythmia in the participants was 2.84% (95%CI) (p > 0.05). Complications were detected during or after the PFA procedure at a rate of 2.23% (p < 0.05), with 95%CI indicating the high safety of the PFA procedure. Using pulsed-field ablation as a new treatment for atrial fibrillation has proven safe and effective.

Improvement in Lesion Formation with Radiofrequency Energy and Utilization of Alternate Energy Sources (Cryoablation and Pulsed Field Ablation) for Ventricular Arrhythmia Ablation

Current ablation systems rely on thermal energy to produce ablation lesions (heating: RF, laser and ultrasound, and cooling: cryo-thermia). While thermal ablation has been proven to be effective, there are several limitations: 1) relatively long procedural times; 2) high recurrence rate of ventricular arrhythmias; and 3) excessive heating potentially leading to serious complications, including steam pop (perforation), coronary arterial injury and thrombo-embolism. Pulsed field ablation (PFA)/irreversible electroporation (IRE) offers a unique non-thermal ablation strategy which has the potential to overcome these limitations. Recent pre-clinical studies suggest that PFA/IRE might be effective and safe for the treatment of cardiac arrhythmias.