Left Atrial Intracardiac Echocardiography to Assist Zero Fluoroscopy Pulse Field Atrial Fibrillation Ablation-A Beginner's Guide.

Funding AcknowledgementsType of funding sources: None.BackgroundComplete electrical pulmonary vein isolation (PVI) by thermal energy sources is a well-established ablation strategy of atrial fibrillation (AF). Recently, a non-thermal ablation approach by means of irreversible cellular electroporation has been made available for clinical use.PurposeWe report the preliminary experience of a new pulsed-field ablation (PFA) system in the context of AF ablation in a multicenter Italian setting.MethodsAll consecutive patients (pts) undergoing AF ablation with PFA at 7 Italian centres were included. Protocol-directed PVI was delivered using 2000 V with eight applications per vein, that is, four applications each in the basket and flower poses. Applications were delivered in pairs at any given catheter position, rotating by ≈30–40° after the first two applications in each configuration. Additional lesions were performed at the operator’s discretion. The ablation endpoint was PVI as assessed by entrance and exit block. Data are reported as median [IQ range].ResultsWith a median of 32[25-38] pts treated per center, a total of 205 cases were included (n=150 73.2%, paroxysmal AF, n=55, 26.9% persistent AF). Of them 187 (91.2%) were de novo cases, whereas 18 (8.8%) were redo cases. A mapping system was used in 55 (21.5%) procedures and an intracardiac echocardiography in 65 (31.7%) cases. The number of PFA applications to reach PVI was 32[32-36]. Procedural parameters were: fluoroscopy time = 16[12-22] min, skin-to-skin time = 60[55-85] min, support time (preparation plus skin-to-skin) =75[64-95] min, lab occupancy time was 97[75-120] min and PFA LA dwell time was 23[20-28] min. The first pass isolation (FPI) rate per vein was 99.6% resulting from 202 patients (98.5%) with FPI. At the end of the procedure, PVI was achieved in all pts (100%) using only PFA. Additional PFA delivery outside PVs was performed in 19% (n=39) of the cases, mostly at the posterior wall area only (n=34, 87%), requiring 16[12-24] PFA deliveries. All the additional lesion sets were validated through differential pacing and/or 3D mapping. The learning curve was extremely fast. After only 5 cases time to PVI and total support time have significantly improved, whereas we did not notice any additional improvement after 10 or 20 cases (LA dwell time: 27[22-32] min during the first 5 cases vs 23[19-27] min after the first 5 cases, p=0.0172; support time: 100[65-120] min vs 75[65-90] min, p=0.0181, respectively). In 13 (6.3%) cases a transient bradycardia or asystole occurred after the first PFA application requiring temporary high-output pacing. No major procedure-related adverse events were reported.ConclusionIn this first multicentric experience, the novel PFA system proved to be safe and effective in both paroxysmal and persistent AF patients. The learning curve seems to be very fast according with procedural parameters.

Pulsed field vs thermal ablation for atrial fibrillation: A Bayesian meta-analysis.

PO-01-005 GANGLIONATED PLEXI MEDIATED BRADYCARDIA RESPONSES: A PRE-CLINICAL STUDY OF DIFFERENCES BETWEEN PULSED FIELD AND RADIOFREQUENCY ABLATION IN THE LEFT ATRIUM

Bachmann’s bundle (BB), also known as the interatrial bundle, is well recognized as a muscular bundle comprising of parallel aligned myocardial strands connecting the right and left atrial walls and is considered to be the main pathway of interatrial conduction.1 Disruption of the bundle’s structure causes interatrial conduction block (IAB),2 which is associated with development of various atrial tachyarrhythmias3,4 and with electromechanical dysfunction of the left atrium.5 Technological progress providing sophisticated mapping and imaging techniques in the past decade has increased our knowledge of specific anatomic structures and their role in development of both atrial brady- and tachyarrhythmias. This review outlines the current knowledge of the relation between anatomic and electrophysiological properties of BB and its possible role in initiation and perpetuation of atrial fibrillation (AF). In 1963, Thomas N. James described 3 pathways connecting the sinus node to the atrioventricular node (AVN), namely the anterior, medial, and posterior internodal pathways.6 Whether these conduction pathways were because of the presence of specialized conduction tissue or because of the anisotropic orientation of the muscle fibers remains controversial. Nevertheless, James described the anterior pathway as leaving the sinus node in anterior direction and giving off a secondary branch at the level of the superior vena cava to form BB.1 BB stretches subepicardially across the interatrial groove (septal raphe). It is at the interatrial groove that the BB can be identified as a discrete bundle (Figures 1 and 2) separated by fatty tissues from the infolded right atrial wall that is the limbus of the oval fossa. Notably, the bundle is not surrounded by a fibrous tissue sheath. Instead, the bundle is comprised of strands of atrial myocardium that are similarly aligned in parallel fashion. Its rightward and leftward extensions bifurcate to pass to either …

IntroductionThe aim of this study was to compare the feasibility, safety, and acute efficacy of pulmonary vein isolation (PVI) and left atrial roof ablation (LARA) using two pulsed field ablation (PFA) catheters – a pentaspline catheter and a circular PFA catheter – in patients with symptomatic atrial fibrillation (AF).MethodsWe enrolled consecutive AF patients who underwent either PVI alone or PVI combined with LARA using the pentaspline catheter (Farapulse™) or the circular array PFA catheter (PulseSelect™ PFA System) between November 2023 and September 2024. LARA was performed only in patients with persistent AF and left atrial enlargement (LA > 20 cm²). Patients with concomitant typical atrial flutter also underwent cavo-tricuspid isthmus (CTI) ablation.ResultsA total of 175 AF patients were included and divided into two groups: group 1 (N = 96) treated with the pentaspline PFA catheter and group 2 (N = 79) treated with the circular PFA catheter.Acute PVI was achieved in 100% of pulmonary veins in both groups. The total number of PFA applications for pulmonary veins (PVs) in group 1 was slightly higher than in group 2 (35 ± 3 vs. 34 ± 3, p < 0.01). In group 1, 29 patients (30.2%) received additional LARA, and 25 patients (31.6%) underwent LARA in group 2 (p = 0.97). LARA was performed with more PFA applications in group 1 than in group 2 (10.8 ± 5.5 vs. 8.5 ± 3.6, p < 0.01). In group 1, three patients received CTI ablation compared to five patients in group 2 (p = 0.47). CTI ablation was achieved with more PFA applications in group 1 (15 ± 6) than in group 2 (6 ± 4, p < 0.01). Conduction block across the left atrial roof and CTI was confirmed in all patients.Procedural times were longer in group 2, including total skin-to-skin time (61.6 ± 16.1 min vs. 67 ± 13.8 min, p < 0.01) and PFA catheter time in the left atrium (41.9 ± 14.0 min vs. 44.6 ± 10.6 min, p < 0.01). However, fluoroscopy time was shorter in group 2 (13.9 ± 5.7 min vs. 13.4 ± 4.7 min, p < 0.01).No significant differences in complication rates were observed between the groups (p = 0.69). Four procedural complications occurred in the pentaspline catheter group (two vascular access complications, one tamponade, and one transient ST elevation), and two vascular complications were noted in group 2.ConclusionThis study demonstrates comparable effectiveness between the two PFA systems for PVI and LARA. Although more PFA applications were performed by pentaspline catheter, the overall procedural time was shorter, while the circular catheter was associated with reduced fluoroscopy time. Both systems showed a similar safety profile. Further studies are needed to evaluate the long-term clinical outcomes of these PFA technologies.

Pulsed field ablation: Biophysical principles and practical considerations in atrial fibrillation treatment.

Wide-area antral pulmonary vein and posterior wall isolation by way of segmental nonocclusive applications using a novel radiofrequency ablation balloon

Background There are limited effective treatment options for persistent atrial fibrillation (AF) patients, with pulmonary veins (PV) isolation alone being considered suboptimal for many patients. Hybrid convergent ablation has been shown to improve clinical outcomes when compared to an endocardial-only radiofrequency (RF) strategy. Pulsed field ablation (PFA) has recently gained growing interest for its efficacy and safety profile in PV and posterior wall (PW) ablation. Objectives To compare clinical outcomes of hybrid convergent RF ablation versus endocardial PFA for PV and PW isolation in patients with persistent AF. Methods From July 2022, 86 persistent AF consecutive patients, receiving endocardial PFA of PV and PW (PFA group, N = 44) or receiving hybrid convergent RF ablation (Hybrid group, N = 42) at our institution were enrolled. Recurrence was defined as any atrial tachyarrhythmia following the 3-month blanking period. Results No differences were found between PFA and Hybrid groups regarding age (PFA 66.0±7.4 years vs Hybrid 63.9±10.6 years; p=0.193) and left atrial volume index (PFA 45.5 [36.7-57.2] ml/m² vs Hybrid 45.0 [39.2-59.7] ml/m²; p=0.920). Differences regarding left ventricular ejection fraction were borderline significant among groups (PFA 55.0 [49.5-62.0]% vs Hybrid 60.5 [52.3-65.0]%; p=0.048), both showing an overall normal LV function. There were no significant differences regarding AF duration (PFA 38.0 months [IQR: 19.2 to 99.0 months] vs Hybrid 70.0 months [IQR: 46.0 to 118.0 months]; p = 0.063). Redo ablation patients’ rate was higher in the hybrid group (PFA n=16, 36.4% vs Hybrid n=28, 66.6%; p&amp;lt;0.001). Procedure duration was Ionger in the hybrid group (179.9±60.1 minutes) compared to PFA endocardial ablation (PFA 106.2±30.7 minute; p&amp;lt;0.01). After a median follow-up of 233.0 [179.0–331.8] days, there was no difference in atrial tachyarrhythmias recurrence rate (PFA n=11, 25.0% vs Hybrid n=10, 23.8%; p=0.897); no difference in the antiarrhythmic drug use rate was found (PFA n=24, 54.5% vs Hybrid n=19, 45.2%; p=0.388). Conclusions PFA of PV and PW, compared with the hybrid convergent ablation strategy, is an endocardial-only, less invasive, and faster procedure. 6-month rhythm outcomes were similar in both groups.

BackgroundPulmonary vein isolation (PVI) is a highly effective therapy for treating atrial fibrillation (AF). PVI using non-thermal pulsed field ablation (PFA) has recently shown comparable outcomes to thermal ablation such as cryoballoon ablation (CBA). Single-shot devices such as CBA and by extension PFA offer several advantages, particularly in reducing ablation time, potentially benefitting patients with comorbidities. Despite increasing prevalence of obesity, there is limited data on the optimal PVI method for this patient population.AimThe aim of this study was to compare procedural data, outcome and complication rates of PFA to CBA in obese patients.MethodsAll de novo PVIs performed at our center between September 2021 and June 2023 using PFA and CBA were analysed. Only obese patients (BMI ≥ 30 kg/m²) undergoing de novo PVI were included in this analysis.ResultsA total of 85 PVI procedures were included. 32 (37.6%) patients underwent PFA and 53 (62.4%) patients received CBA. Baseline characteristics were comparable between groups. In the PFA group (65.6% male; mean age 67.7 ± 8.0 years), 68.8% of patients suffered from persistent AF, with an average BMI of 33.3 ± 3.0 kg/m². In the CBA group (73.6% male; mean age 64.3 ± 10.3 years), 47.2% of patients suffered from persistent AF, and the average BMI was 33.0 ± 2.9 kg/m². Procedure time was significantly shorter with PFA compared to CBA (PFA: 57.0 ± 19.7 min; CBA: 64.7 ± 17.3 min; p=0.0167), and the use of contrast medium was significantly lower in the PFA group (PFA: 10.9 ± 8.7 ml; CBA: 47.2 ± 23.0 ml; p<0.0001), while fluoroscopy time (PFA: 12.2 ± 4.2 min; CBA: 11.2 ± 4.2 min, p=0.2) and dose (PFA: 6872.8 ± 11072.8 mGy·cm2; CBA: 7834.5 ± 13419.2 mGy·cm2; p=0.6) were comparable. Major complications in the PFA group were one pericardial tamponade, and two intermittent sinus arrests. In the CBA group one patient experienced a pseudoaneurysm and one patient developed pneumonia due to aspiration (PFA: n=3, 9.4%; cryo: n=2; 3.8%; p=0.3). After a mean follow-up of 310.2 days, 83.3% of patients in the PFA group and 77.4% in the CBA group were free from atrial arrhythmia, with no significant difference in the survival analysis (p=0.6, log-rank HR 0.75, 95% CI 0.28–2.04).ConclusionIn obese patients, PFA is comparably safe and effective to achieve complete PVI with the potentially added benefit of a shorter procedure time and reduced contrast medium usage compared to CBA. However, this study primarily included patients with class one obesity and only few with higher-grade obesity. Risks associated with ablation may increase in patients with higher grade of obesity and PFA might be even more beneficial for these patients.Figure 1:Kaplan-Meier analysis

Automated detection and characterization of complex fractionated atrial electrograms in human left atrium during atrial fibrillation

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.

Image integration of three-dimensional (3D) reconstructions of left atrial (LA) and pulmonary vein (PV) anatomy into electroanatomical mapping (EAM) plays a major role in atrial fibrillation (AF) ablation. Point-by-point EAM is commonly used for registration of imported LA and PV anatomy. We aimed to assess the accuracy of intraprocedural rotational angiography-based LA imaging registered by spatial reconstruction of intracardiac echocardiography (ICE) in patients undergoing AF ablation. Twenty-two patients (11 males, 66 ± 12 years) were studied. Reconstructions of LA and PVs based on rotational angiography were registered by a second 3D reconstruction based on ICE. In a second step, EAM points were added to ICE 3D reconstructions. A 3D image of the LA and PVs was reconstructed in all patients by both imaging modalities. Rotational angiography and ICE-based LA 3D reconstructions took 11.5 ± 5.2 and 20.4 ± 11.2 min, respectively. A total of 17 ± 6 two-dimensional ICE fans were used for spatial reconstruction of ICE. The deviation between the two 3D shells was 2.6 ± 0.5 mm. Integration of 78 ± 58 EAM points into ICE 3D reconstruction did not significantly reduce the deviation to rotational angiography-based reconstructions (2.7 ± 0.6 mm). All PVs were isolated successfully. Intraprocedural 3D reconstruction of LA and PVs for ablation of AF is feasible based on both rotational angiography and ICE. LA reconstructions based on rotational angiography can accurately be registered using 3D ICE shells. Additional EAM does not enhance accuracy. Therefore, registration of rotational angiography-based 3D reconstructions by 3D reconstructions from ICE seems to be an alternative technique to support AF ablation.

The circular array (CA) pulsed field ablation (PFA) system is the first FDA-approved PFA technology for atrial fibrillation (AF), but real-world long-term outcome data remain limited. To compare 1-year procedural outcomes and arrhythmia recurrence following CA PFA versus clinically matched radiofrequency (RF) ablation. In this prospective single-center study, 36 consecutive patients underwent de novo AF ablation with the CA catheter and were matched 1:1 to RF controls by age, sex, left atrial size, body mass index, ejection fraction, and AF type. A previously described lesion optimization strategy with pole 5 anchoring was applied in all PFA cases. The primary endpoint was a composite of AF recurrence, antiarrhythmic use, cardioversion beyond the blanking period, or repeat ablation at 1 year. Baseline characteristics were similar between groups. Procedure and left atrial dwell times were significantly shorter with CA PFA (124 vs. 179 min; 72 vs. 115 min; both p < 0.001). No complications occurred in the PFA group, compared with two access-site hematomas in RF. The composite endpoint occurred less often with PFA (22% vs. 36%, p = 0.195). In multivariable analysis, PFA was associated with a lower risk of recurrence (aOR: 0.50, p = 0.081). CA PFA, performed with lesion optimization techniques, was safe, efficient, and at least as effective as RF ablation at 1 year. This study represents the first controlled, real-world comparison of long-term outcomes between CA PFA and RF ablation.

The newly introduced nonthermal pulsed field ablation (PFA) is a promising technology to achieve fast pulmonary vein isolation (PVI) with high acute success rates and good safety features. However, previous studies have shown that very high power short duration ablation (VHPSD) is also highly effective and fast to achieve PVI with potentially less arrhythmia recurrence compared to conventional radiofrequency ablation. Data comparing PFA to VHPSD-PVI is lacking. This study compared procedural and outcome data for PFA-PVI to VHPSD-PVI in patients with paroxysmal or persistent atrial fibrillation (PAF/persAF). Consecutive patients undergoing de novo PVI (PFA or VHPSD) were included in this analysis. For PFA-PVI a pentaspline 20 electrode catheter was used. For VHPSD-PVI an enhanced irrigated catheter with a power setting of 70 W/7 s (70 W/5 s at posterior wall) was employed in conjunction with electro-anatomical mapping. All procedures were performed in deep analgo-sedation. A total of n = 114 patients (n = 57[50%] PFA, n = 17[30%] PAF; n = 40[70%] persAF) were included in this analysis. PVI was successful in all patients. The PFA group revealed a significantly shorter procedure duration (65 ± 17 min vs. 95 ± 23 min, p < 0.01) but longer fluoroscopy time (PFA 15 ± 5 min and VHPSD 12 ± 3 min; p < 0.001). At follow-up after median 125 days (interquartile range: 109-162) n = 46 PFA (80.7%) and n = 44 VHPSD pts (77.2%) were free from atrial arrhythmia after a single procedure (p = 0.819). Two tamponades occurred in the PFA while in VHPSD two pts suffered groin bleedings. One clinically nonsignificant PV stenosis occurred in the VHPSD group. Pulsed-field ablation and VHPSD-PVI seem to be highly effective and safe to achieve PVI in the setting of PAF and persAF with comparable arrhythmia-free survival. However, procedure duration for PFA PVI is significantly shorter and therefore may be of potential benefit. Compared to PFA VHPSD-PVI might ensure information on left atrial substrate allowing to target concomitant secondary tachycardias.

Background Pulsed field ablation (PFA) represents a novel promising non-thermal alternative in non-pharmacological treatment of atrial fibrillation (AF). However, infrequent cases of acute renal failure secondary to intravascular haemolysis after a PFA procedure have been described. Objective To investigate the impact of ablation technology (PFA vs. radiofrequency ablation (RFA)) on the level of plasma cell-free haemoglobin (CFH) and the concentration of serum neutrophil gelatinase-associated lipocalin (NGAL) as a marker of tubular injury. Methods This was a prospective observational trial. In a consecutive cohort of patients who underwent AF ablation (PFA of RFA), blood samples were drawn just before the procedure (Sample 1: CFH and NGAL), immediately after the procedure (Sample 2: CFH) and one day after the procedure (Sample 3: CFH and NGAL). Plasma CHF level and serum NGAL concentration were analysed using the ELISA technique. Results Among 70 patients enrolled (mean age 64.3 ± 10.3 years, 61 % male), 23 underwent RFA and 47 PFA (22 pulmonary vein isolation (PVI) only and 25 PVI with other additive lesions). Baseline serum creatinine levels of both groups were comparable (91.7 ± 22.1 µmol/L vs. 88.8 ± 22.1 µmol/L P = 0.44). In the PFA cohort, a significant peak of CFH concentration was observed just after the procedure with a subsequent decrease within 12 hours (Sample 1 vs. Sample 2: 93.4 ± 65.1 µg/mL vs. 2394.9 ± 1966.1 µg/mL P &amp;lt; 0.001, Sample 1 vs. Sample 3: 93.4 ± 65.1 µg/mL vs. 97.2 ± 68.5 µg/mL P = 0.75). No significant differences were observed in the RFA cohort. Compared to baseline, neither the PFA nor the RFA group showed a significant difference in NGAL levels (PFA 98.6 ± 31.7 ng/mL vs. 98.5 ± 38.1 ng/mL P = 0.78, RFA 108.3 ± 33.8 ng/mL vs. 116.3 ± 32.2 ng/mL P = 0.49). Conclusions Compared to RFA, PFA leads to significant peri-procedural haemolysis. However, no differences in the concentration of the tubular injury marker NGAL were observed on the first day after the procedure.