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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

First-in-human clinical series of a novel conformable large-lattice pulsed field ablation catheter for pulmonary vein isolation.

AIMS: Pulsed field ablation (PFA) has significant advantages over conventional thermal ablation of atrial fibrillation (AF). This first-in-human, single-arm trial to treat paroxysmal AF (PAF) assessed the efficiency, safety, pulmonary vein isolation (PVI) durability and one-year clinical effectiveness of an 8 Fr, large-lattice, conformable single-shot PFA catheter together with a dedicated electroanatomical mapping system. METHODS AND RESULTS: After rendering the PV anatomy, the PFA catheter delivered monopolar, biphasic pulse trains (5-6 s per application; ∼4 applications per PV). Three waveforms were tested: PULSE1, PULSE2, and PULSE3. Follow-up included ECGs, Holters at 6 and 12 months, and symptomatic and scheduled transtelephonic monitoring. The primary and secondary efficacy endpoints were acute PVI and post-blanking atrial arrhythmia recurrence, respectively. Invasive remapping was conducted ∼75 days post-ablation. At three centres, PVI was performed by five operators in 85 patients using PULSE1 (n = 30), PULSE2 (n = 20), and PULSE3 (n = 35). Acute PVI was achieved in 100% of PVs using 3.9 ± 1.4 PFA applications per PV. Overall procedure, transpired ablation, PFA catheter dwell and fluoroscopy times were 56.5 ± 21.6, 10.0 ± 6.0, 19.1 ± 9.3, and 5.7 ± 3.9 min, respectively. No pre-defined primary safety events occurred. Upon remapping, PVI durability was 90% and 99% on a per-vein basis for the total and PULSE3 cohort, respectively. The Kaplan-Meier estimate of one-year freedom from atrial arrhythmias was 81.8% (95% CI 70.2-89.2%) for the total, and 100% (95% CI 80.6-100%) for the PULSE3 cohort. CONCLUSION: Pulmonary vein isolation (PVI) utilizing a conformable single-shot PFA catheter to treat PAF was efficient, safe, and effective, with durable lesions demonstrated upon remapping.

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.

Electrographic flow mapping of persistent atrial fibrillation: intra- and inter-procedure reproducibility in the absence of 'ground truth'.

AIMS: Validating mapping systems that identify atrial fibrillation (AF) sources (focal/rotational activity) is confounded by the absence of ground truth. A key concern of prior mapping technologies is spatiotemporal instability, manifesting as poor map reproducibility. Electrographic flow (EGF) employs a novel algorithm that visualizes atrial electrical wavefront propagation to identify putative AF sources. We analysed both intra- (3 min) and inter- (>3 months) procedure EGF map reproducibility. METHODS AND RESULTS: In 23 persistent AF patients, after pulmonary vein isolation (PVI), EGF maps were generated from 3 serial 1 min recordings using a 64-electrode basket mapping catheter (triplets) at right and left atrial locations. Source prevalence from map triplets was compared between recordings. Per protocol, 12 patients returned for 3-month remapping (1 non-inducible): index procedure post-PVI EGF maps were compared with initial EGF remapping at 3-month redo. Intra-procedure reproducibility: analysing 224 map triplets (111 right atrium, 113 left atrium) revealed a high degree of map consistency with minimal min-to-min shifts: 97 triplets (43%), exact match of leading sources on all 3 maps; 95 triplets (42%), leading source within 1 electrode space on 2 of 3 maps; and 32 triplets (14%), chaotic leading source pattern. Average deviation in source prevalence over 60 s was low (6.4%). Inter-procedure reproducibility: spatiotemporal stability of EGF mapping >3 months was seen in 16 of 18 (89%) sources mapped in 12 patients with (re)inducible AF. CONCLUSION: Electrographic flow mapping generates reproducible intra- and inter-procedural maps, providing rationale for randomized clinical trials targeting these putative AF sources.

Multi-national survey on the methods, efficacy, and safety on the post-approval clinical use of pulsed field ablation (MANIFEST-PF).

AIMS: Pulsed field ablation (PFA) is a novel atrial fibrillation (AF) ablation modality that has demonstrated preferential tissue ablation, including no oesophageal damage, in first-in-human clinical trials. In the MANIFEST-PF survey, we investigated the 'real world' performance of the only approved PFA catheter, including acute effectiveness and safety-in particular, rare oesophageal effects and other unforeseen PFA-related complications. METHODS AND RESULTS: This retrospective survey included all 24 clinical centres using the pentaspline PFA catheter after regulatory approval. Institution-level data were obtained on patient characteristics, procedure parameters, acute efficacy, and adverse events. With an average of 73 patients treated per centre (range 7-291), full cohort included 1758 patients: mean age 61.6 years (range 19-92), female 34%, first-time ablation 94%, paroxysmal/persistent AF 58/35%. Most procedures employed deep sedation without intubation (82.1%), and 15.1% were discharged same day. Pulmonary vein isolation (PVI) was successful in 99.9% (range 98.9-100%). Procedure time was 65 min (38-215). There were no oesophageal complications or phrenic nerve injuries persisting past hospital discharge. Major complications (1.6%) were pericardial tamponade (0.97%) and stroke (0.4%); one stroke resulted in death (0.06%). Minor complications (3.9%) were primarily vascular (3.3%), but also included transient phrenic nerve paresis (0.46%), and TIA (0.11%). Rare complications included coronary artery spasm, haemoptysis, and dry cough persistent for 6 weeks (0.06% each). CONCLUSION: In a large cohort of unselected patients, PFA was efficacious for PVI, and expressed a safety profile consistent with preferential tissue ablation. However, the frequency of 'generic' catheter complications (tamponade, stroke) underscores the need for improvement.

Left atrial thickness and acute thermal injury in patients undergoing ablation for atrial fibrillation: Laser versus radiofrequency energies.

INTRODUCTION: Thermally induced cardiac lesions result in necrosis, edema, and inflammation. This tissue change may be seen with ultrasound. In this study, we sought to use intracardiac echocardiography (ICE) to evaluate pulmonary vein tissue morphology and assess the acute tissue changes that occur following radiofrequency (RF) or laser ablation for atrial fibrillation (AF). METHODS AND RESULTS: Patients with AF underwent pulmonary vein isolation (PVI) using irrigated RF or laser balloon. Pre- and post-ablation ICE imaging was performed from within each pulmonary vein (PV). At least 10 transverse imaging planes per PV were evaluated and each plane was divided into eight segments. The PV/atrial wall thickness and the luminal area were measured at each segment. Twenty-seven patients underwent PVI (15 with laser, 12 with RF). Ninety-eight pulmonary veins were analyzed (58 PVs laser; 40 PVs RF). At baseline, there were no regional differences in PV wall thickness in the right-sided veins. The anterior regions of left superior pulmonary vein (LSPV) and left inferior pulmonary vein (LIPV) were significantly thicker compared with the posterior and inferior regions (p < .01). Post-ablation, PV wall thickness in RF group increased 24.1% interquartile range (IQR) (17.2%-36.7%) compared with 1.2% IQR (0.4%-8.9%) in laser group, p = .004. In all PVs, RF ablation resulted in significantly greater percent increase in wall thickness compared with laser. Additionally, RF resulted in more variable changes in regional PV wall thickness; with more increases in wall thickness in anterior versus posterior LSPV (75.4 ± 58.5% vs. 46.8 ± 55.6%, p < .01), anterior versus posterior right superior pulmonary vein (RSPV) (62.9 ± 63.9% vs. 44.6 ± 51.7%, p < .05), and superior versus inferior RSPV (69.1 ± 45.4% vs. 35.9 ± 45%, p < .05). There were no significant regional differences in PV wall thickness changes for the laser group. CONCLUSIONS: Rotational ICE can be used to measure acute tissue changes with ablation. Regional variability in baseline wall thickness was nonuniformly present in PVs. Acute tissue changes occurred immediately post-ablation. Compared with laser balloon, RF shows markedly more thickening post-ablation with significant regional variations.

Intracardiac echocardiography-guided implantation of the Watchman FLX left atrial appendage closure device.

BACKGROUND: The next-generation Watchman FLX left atrial appendage closure (LAAC) device has: (1) an atraumatic closed distal end, (2) reduced height, (3) a recessed screw hub to decrease device-related thrombus (DRT), (4) two rows of J-shape anchors so redeployment is possible after full recapture, and (5) ability to treat a greater size range of LAA ostia. OBJECTIVE: To report, for the first time, the feasibility and safety of intracardiac echocardiography (ICE)-guided Watchman FLX implantation. METHODS: A single-center prospective registry of atrial fibrillation patients planned for LAAC with the FLX device underwent ICE-guided implantation with conscious sedation. Transesophageal echocardiography (TEE) imaging was done preprocedure (to assess LAA size and exclude thrombus) and at clinical follow-up at 6-12 weeks. Clinical outcomes were LAA closure success, complications, leak, or DRT on follow-up TEE and major safety events. RESULTS: The study included 30 patients: age 75 ± 8 years, 53% men, CHA2 DS2 -VASc 4.6 ± 1.6, and HAS-BLED 3.4 ± 1.1. The primary indication was prior bleeding in 60% (72% GI bleeding). The LAA orifice width and length were 22.7 ± 3.1 and 25.7 ± 5.7 mm, respectively. Technical success was 100% (the first-choice device was used in 28 of 30). Procedure time was less than 30 min in 27 of 30 cases, with 36 ± 15 ml contrast used. The final device size was 29.2 ± 4.7 mm with 21.6 ± 4.5% compression. There were no procedure-related complications. Follow-up TEE at a median 47 days follow-up showed 100% device success with no DRT or peridevice leak ≥5 mm. Major safety events occurred in 6.6% (2/30). CONCLUSION: The Watchman FLX device can be safely implanted with intraprocedural ICE imaging instead of TEE.

How does the level of pulmonary venous isolation compare between pulsed field ablation and thermal energy ablation (radiofrequency, cryo, or laser)?

AIMS: We studied the extent/area of electrical pulmonary vein isolation (PVI) after either pulsed field ablation (PFA) using a pentaspline catheter or thermal ablation technologies. METHODS AND RESULTS: In a clinical trial (NCT03714178), paroxysmal atrial fibrillation (PAF) patients underwent PVI with a multi-electrode pentaspline PFA catheter using a biphasic waveform, and after 75 days, detailed voltage maps were created during protocol-specified remapping studies. Comparative voltage mapping data were retrospectively collected from consecutive PAF patients who (i) underwent PVI using thermal energy, (ii) underwent reablation for recurrence, and (iii) had durably isolated PVs. The left and right PV antral isolation areas and non-ablated posterior wall were quantified. There were 20 patients with durable PVI in the PFA cohort, and 39 in the thermal ablation cohort [29 radiofrequency ablation (RFA), 6 cryoballoon, and 4 visually guided laser balloon]. Pulsed field ablation patients were younger with shorter follow-up. Left atrial diameter and ventricular systolic function were preserved in both cohorts. There was no significant difference between the PFA and thermal ablation cohorts in either the left- and right-sided PV isolation areas, or the non-ablated posterior wall area. The right superior PV isolation area was smaller with PFA than RFA, but this disappeared after propensity score matching. Notch-like normal voltage areas were seen at the posterior aspect of the carina in the balloon sub-cohort, but not the PFA or RFA cohorts. CONCLUSION: Catheter-based PVI with the pentaspline PFA catheter creates chronic PV antral isolation areas as encompassing as thermal energy ablation.

Catheter Ablation of Ischemic Ventricular Tachycardia With Remote Magnetic Navigation: STOP-VT Multicenter Trial.

INTRODUCTION: Catheter ablation is an effective treatment of scar-related ventricular tachycardia (VT), but the overall complexity of the procedure has precluded its widespread use. Remote magnetic navigation (RMN) has been shown to facilitate cardiac mapping and ablation of VT in a retrospective series. STOP-VT is the first multicenter, prospective, single-arm and single-procedure study evaluating RMN-based mapping and ablation of post-infarction VT. METHODS: Patients with documented VT and prior MI, in whom an ICD was implanted either for primary or secondary prevention, were recruited from four EU and US centers. Either a transseptal (48 patients) or transaortic (5 patients) approach was employed to gain access for ventricular endocardial mapping/ablation during VT (entrainment mapping, activation mapping) and/or substrate mapping in sinus rhythm (elimination of fractionated/late potentials, variable extent of substrate modification) with RMN and irrigated RF ablation. The primary endpoints were as follows: (i) non-inducibility of the target VT or any other sustained VT; (ii) elimination of sustained VT/VF during ICD follow-up of up to 12 months. RESULTS: The cohort included 53 consecutive patients (median age 67 years, 49 men, median LVEF 31%). One hemodynamically unstable patient was excluded at the onset of mapping. Inducibility of sustained VT was achieved an average of 2.2 times per patient (1-8), with mean tachycardia cycle length (TCL) 374 milliseconds (179-510). Mean total procedure and fluoroscopy times were 223 minutes and 8.7 minutes, respectively; mean cumulative fluoroscopy time during mapping and ablation was 0.95 minutes; maximum power averaged 42.3 W with nominal saline 30 cc/min irrigation; mean cumulative RF time was 38 minutes. Non-inducibility of the target VT was achieved in 49/52 patients (94.2%) and non-inducibility of any VT was achieved in 38/52 patients (73.1%). A combination of RMN and manual ablation was performed in two patients, rendering one non-inducible. During the 12-month ICD follow-up period, freedom from any sustained VT/VF was observed in 30 patients (62%), of which 19 (63%) were off antiarrhythmic medications. Five patients expired during follow-up: one presented with a VT storm, but for the others, death was not related to VT/VF (MI-cardiogenic shock, pulmonary embolism, bronchogenic carcinoma, end stage heart failure). No procedural complications were reported. CONCLUSIONS: This first prospective, single-procedure, multicenter study indicates that remote magnetic navigation is a safe and effective method for catheter ablation of post-infarction VT.

Permanent leadless cardiac pacing: results of the LEADLESS trial.

BACKGROUND: Conventional cardiac pacemakers are associated with several potential short- and long-term complications related to either the transvenous lead or subcutaneous pulse generator. We tested the safety and clinical performance of a novel, completely self-contained leadless cardiac pacemaker. METHODS AND RESULTS: The primary safety end point was freedom from complications at 90 days. Secondary performance end points included implant success rate, implant time, and measures of device performance (pacing/sensing thresholds and rate-responsive performance). The mean age of the patient cohort (n=33) was 77±8 years, and 67% of the patients were male (n=22/33). The most common indication for cardiac pacing was permanent atrial fibrillation with atrioventricular block (n=22, 67%). The implant success rate was 97% (n=32). Five patients (15%) required the use of >1 leadless cardiac pacemaker during the procedure. One patient developed right ventricular perforation and cardiac tamponade during the implant procedure, and eventually died as the result of a stroke. The overall complication-free rate was 94% (31/33). After 3 months of follow-up, the measures of pacing performance (sensing, impedance, and pacing threshold) either improved or were stable within the accepted range. CONCLUSIONS: In a prospective nonrandomized study, a completely self-contained, single-chamber leadless cardiac pacemaker has shown to be safe and feasible. The absence of a transvenous lead and subcutaneous pulse generator could represent a paradigm shift in cardiac pacing. CLINICAL TRIAL REGISTRATION URL: http://clinicaltrials.gov. Unique identifier: NCT01700244.

Durability of Pulmonary Vein Isolation with Cryoballoon Ablation: Results from the Sustained PV Isolation with Arctic Front Advance (SUPIR) Study.

INTRODUCTION: Pulmonary vein (PV) reconnection remains the most important cause of AF recurrence after AF ablation. The second-generation cryoballoon catheter's ability to achieve durable PV isolation was assessed in a prospective nonrandomized clinical trial. METHODS AND RESULTS: PV isolation was performed by 4-minute ablations. Following verification of electrical isolation by a multielectrode mapping catheter, 1 additional lesion per PV was applied. Esophageal temperatures were monitored and all patients underwent postprocedure esophageal endoscopy. All patients underwent a second PV remapping procedure at ∼3 months to assess for PVI durability. Eighty-four (100%) veins were acutely isolated using only the 28 mm cryoballoon in 21 consecutive PAF patients with 2.2 ± 0.6 cryoapplications per vein, with the majority (83%) occurring after a single freeze. One patient presented with hematemesis and an esophageal ulceration that was treated conservatively; there were no episodes of esophageal fistula or phrenic nerve palsy. At 3.4 (2.9-4.1) months postablation, 68/75 veins (91%) remained electrically isolated; all PVs remained durably isolated in 79% of patients. Two patients accounted for 5 of 7 reconducting veins. The most common site for reconnection was the inferior aspect of the RIPV (3/7 reconnections). Reconnected veins had poorer occlusion at the index ablation procedure than veins that maintained chronic isolation (occlusion grade 2.9 ± 0.7 vs. 3.4 ± 0.7, P = 0.001). Clinical AF recurrence was detected in 2 patients (11%) at follow-up. CONCLUSIONS: The improved thermodynamic characteristics of the second-generation cryoballoon led to a high rate of both single-shot PVI and chronic lesion durability. This high rate of durable PV isolation is anticipated to translate to improved clinical outcome.

EFFICAS II: optimization of catheter contact force improves outcome of pulmonary vein isolation for paroxysmal atrial fibrillation.

AIMS: A challenge of pulmonary vein isolation (PVI) in catheter ablation for paroxysmal atrial fibrillation (PAF) is electrical reconnection of the PV. EFFICAS I showed correlation between contact force (CF) parameters and PV durable isolation but no prospective evaluation was made. EFFICAS II was a multicentre study to prospectively assess the impact of CF guidance for an effective reduction of PVI gaps. METHODS AND RESULTS: Pulmonary vein isolation using a radiofrequency (RF) ablation catheter with an integrated force sensor (TactiCath™) was performed in patients with PAF. Operators were provided EFFICAS I-based CF guidelines [target 20 g, range 10-30 g, minimum 400 g s force-time integral (FTI)]. Conduction gaps were assessed by remapping of PVs after 3 months, and gap rate was compared with EFFICAS I outcome. At follow up, 24 patients had 85% of PVs remaining isolated, compared with 72% in EFFICAS I (P = 0.037) in which CF guidelines were not used. The remaining 15% of gaps correlated to the number of catheter moves at creating the PVI line, quantified as Continuity Index. For PV lines with contiguous lesions and low catheter moves, durable isolation was 81% in EFFICAS I and 98% in EFFICAS II (P = 0.005). At index procedure, the number of lesions was reduced by 15% in EFFICAS II vs. EFFICAS I. CONCLUSION: The use of CF with the above guidelines and contiguous deployment of RF lesions in EFFICAS II study resulted in more durable PVI in catheter ablation of PAF.

Visually guided laser ablation: a single-centre long-term experience.

AIMS: Durable isolation of the pulmonary veins (PVs) remains the cornerstone of treatment for paroxysmal atrial fibrillation (PAF) and is also used in the treatment of some patients with persistent atrial fibrillation. Visually guided laser ablation (VGLA) has been proven to be safe and effective as a treatment for atrial fibrillation (AF). It has shown high levels of durable PV isolation (PVI), even in the hands of less experienced users. This paper presents the long-term clinical outcomes of all patients treated with VGLA over the course of 4 years in the world's most experienced centre: from early product feasibility work treating only PAF patients to our work using the commercially available product, when we also treated persistent AF patients. METHODS AND RESULTS: One hundred and ninety-four patients (63 females, mean age 61 years) with either a history of drug-refractory PAF (time since initial diagnosis: 60.73 months) or persistent AF (time since initial diagnosis: 62.75 months) were treated in our laboratory with VGLA between 7 January 2009 and 17 May 2013. Follow-up of all patients was consistent with our standard clinical practice with a 7-day Holter being performed at the first clinical visit between 4 and 6 months and, for most patients, again at 12 months post-procedure. Twelve lead electrocardiograms were performed at all clinical visits. Recurrence of AF is defined as any documented AF episode >30 s. Acute procedural results show that 692 veins were acutely isolated with a mean procedure and fluoroscopy time of 226 and 20.4 min, respectively. One hundred and seventy (158 PAF and 12 persistent AF) patients reached 1 year of follow-up, 130 (82.3%) patients remained free of AF in the PAF group, and 9 (75%) in the persistent group. Eighty-seven PAF patients have now reached 24 months follow-up and 66 (75.9%) remain free of AF. Fifty-four PAF patients have reached 36 months follow-up with 41 (75.9%) remaining free of AF. Thirty-two PAF patients have reached 48 months follow-up and 24 (75%) remain free of AF. The peri-procedural complications we encountered were phrenic nerve injury in four patients (2.06%), tamponade or pericardial effusion in one patient (0.51%), stroke or transient ischaemic attack in one patient (0.514%), and vascular injury in six patients (3.09%). We experienced no cases of PV stenosis or atrio-oesophageal fistula. CONCLUSION: Our single-centre experience using VGLA over 4 years shows that it can be used safely and effectively in normal clinical practice and gives high levels of acute PVI accompanied by good clinical outcomes, even after long-term follow-up.

Asymptomatic brain lesions following laserballoon-based pulmonary vein isolation.

AIMS: Laserballoon-based pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF) has proven safe and effective. Silent brain lesions after AF ablation detected on magnetic resonance imaging (MRI) have been described for several technologies, but its incidence following laserballoon PVI is unknown. The current study sought to assess the incidence of new asymptomatic brain lesions in patients undergoing laserballoon-based PVI. METHODS AND RESULTS: Patients referred for PVI underwent pre- and post-procedural MRI of the brain. A total of 86 patients were enroled into the study (laserballoon group: 44 patients, 15 female, age 63 ± 9 years, left atrial (LA) diameter 43 ± 5 mm; cryoballoon group: 20 patients, 6 female, age 61 ± 9 years, LA diameter 41 ± 4 mm; and irrigated radiofrequency (RF) group: 22 patients, 11 female, age 64 ± 8 years, LA diameter 43 ± 6 mm). There was no statistically significant difference between the groups with regard to new asymptomatic brain lesions detected on post-procedural MRI: 5 of 44 (11.4%) patients in the laserballoon group, 1 of 20 (5.0%) patients in the cryoballoon group, and 4 of 22 (18.2%) patients in the irrigated RF group, respectively. In the laserballoon group, one additional patient with a new cerebral lesion experienced transient diplopia. In a multivariate regression model the only risk factor for asymptomatic new lesions was the CHA2DS2VASc score. CONCLUSION: Following laserballoon-based PVI, new asymptomatic brain lesions were detected in 11.4% of patients. A higher CHA2DS2VASc score, but not the ablation technology utilized, was the only associated risk factor.

Coronary Artery Spasm During Pulsed Field vs Radiofrequency Catheter Ablation of the Mitral Isthmus.

Importance: In treating atrial fibrillation, pulsed field ablation (PFA) is a novel energy modality with comparable efficacy to conventional thermal ablation, such as radiofrequency ablation (RFA), but with the benefit of some preferentiality to myocardial tissue ablation. Studies have demonstrated important safety advantages, including the absence of esophageal injury or pulmonary vein stenosis and only rare phrenic nerve injury. However, there is emerging evidence of coronary artery vasospasm provoked by PFA. Objective: To compare the incidence and severity of left circumflex arterial vasospasm between PFA and RFA during adjacent ablation along the mitral isthmus. Design, Setting, and Participants: This prospective cohort study enrolled consecutive adult patients receiving first-ever PFA or RFA of the mitral isthmus during catheter ablation of atrial fibrillation in 2022 with acute follow-up at a single referral European center. Exposure: A posterolateral mitral isthmus line was created using either a multielectrode pentaspline PFA catheter (endocardial ablation) or a saline-irrigated RFA catheter. Simultaneous diagnostic coronary angiography was performed before, during, and after catheter ablation. Nitroglycerin was planned for spasm persisting beyond 20 minutes or for significant electrocardiographic changes. Main Outcomes and Measures: The frequency and severity of left circumflex arterial vasospasm was assessed and monitored, as were time to remission and any need for nitroglycerin administration. Results: Of 26 included patients, 19 (73%) were male, and the mean (SD) age was 65.5 (9.3) years. Patients underwent either PFA (n = 17) or RFA (n = 9) along the mitral isthmus. Coronary spasm was observed in 7 of 17 patients (41.2%) undergoing PFA: in 7 of 9 (77.8%) when the mitral isthmus ablation line was situated superiorly and in 0 of 8 when situated inferiorly. Conversely, coronary spasm did not occur in any of the 9 patients undergoing RFA. Of 5 patients in whom crossover PFA was performed after RFA failed to achieve conduction block, coronary spasm occurred in 3 (60%). Most instances of spasm (9 of 10 [90%]) were subclinical, with 2 (20%) requiring nitroglycerin administration. The median (range) time to resolution of spasm was 5 (5-25) minutes. Conclusion and Relevance: When creating a mitral isthmus ablation line during catheter ablation of atrial fibrillation, adjacent left circumflex arterial vasospasm frequently occurred with PFA and not RFA but was typically subclinical.

Acute and long-term results with the 3rd generation visually guided laser balloon ablation system for pv isolation.

BACKGROUND: Visually guided laser balloon ablation is known as an effective pulmonary vein (PV) isolation device. The third-generation laser balloon ablation system (X3) equipped with compliant balloon and an automated motor-driven laser output mechanism, namely RAPID mode, has been clinically proven for PV isolation. METHODS: PV isolation with X3 was performed in all the patients with paroxysmal and early-stage persistent atrial fibrillation (AF). Acute data for PV isolation and clinical outcomes including supraventricular tachyarrhythmia (SVT: AF, atrial flutter, or atrial tachycardia)-free survival rate beyond 1 year were analyzed. RESULTS: A total of 110 patients (62 ± 13 years old, 80% of paroxysmal AF) were treated with X3. RAPID mode with was utilized to achieve PV isolation in all cases. In combination with RAPID mode and spot mode laser ablation, 91.1% (380/417) of veins were isolated on the first circumferential lesion set and did not require touch-up ablation and during the index procedure 100% of attempted veins were isolated. The mean procedure time was 77.0 ± 22.7 min and LA dwell time was 61.9 ± 22.0 min. Total duration of laser application was 5.1 ± 2.3 min per vein. At 1 year, SVT-free survival rate was 93.7% in paroxysmal AF patients, and 81.1% in persistent AF patients. CONCLUSIONS: A novel continuous automatic laser balloon ablation system was proved to be safe and effective for both paroxysmal and persistent AF patients. The clinical result demonstrated that PV isolation with X3 could achieve a high SVT-free survival rate.

AF ablation using a novel "single-shot" map-and-ablate spherical array pulsed field ablation catheter: 1-Year outcomes of the first-in-human PULSE-EU trial.

BACKGROUND: During pulsed field ablation (PFA), electrode-tissue proximity optimizes lesion quality. A novel "single-shot" map-and-ablate spherical multielectrode PFA array catheter that is able to verify electrode-tissue contact was recently studied in a first-in-human trial of atrial fibrillation (AF). OBJECTIVE: The aim of this study was to report lesion durability data, safety, and 12-month effectiveness outcomes. METHODS: The spherical PFA catheter, an all-in-one mapping and ablation system, was used to render anatomy and to deliver biphasic pulses (ungated 1.7 kV pulses; ∼40 seconds/application). Ablation sites included pulmonary veins (PVs) and, in selected patients, posterior wall and mitral isthmus. Follow-up was invasive remapping at ∼3 months, electrocardiograms, Holter monitoring at 6 and 12 months, and symptomatic and scheduled transtelephonic monitoring. The primary and secondary efficacy end points were acute PV isolation (PVI), PVI durability, and atrial arrhythmia recurrence. RESULTS: In the 48-patient AF cohort (paroxysmal, 48%; persistent, 52%), lesion sets included PVI (n = 48; 1.2 applications/PV), posterior wall (n = 20; 3.6 applications/posterior wall), and mitral isthmus (n = 11; 2.9 applications/mitral isthmus). Lesions were acutely successful for all 187 of 187 PVs (100%), 20 of 20 posterior walls (100%), and 10 of 11 mitral isthmuses (91%). Pulse delivery time, left atrial catheter dwell time, and procedure time were 61.5 ± 32.8 seconds, 53.9 ± 26.5 minutes, and 87.8 ± 29.8 minutes, respectively. Remapping (43/48 patients [89.5%]) revealed that 158 of 169 PVs (93.5%) were durably isolated. The only complication was a drug-responsive pericarditis. The 1-year Kaplan-Meier estimates of freedom from atrial arrhythmia were 84.2% (paroxysmal AF) and 80.0% (persistent AF). CONCLUSION: The single-shot spherical array PFA catheter can safely achieve durable lesions, translating into good clinical efficacy. GOV IDENTIFIER: NCT05164107.

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

BACKGROUND: In treating atrial fibrillation, pulsed-field ablation (PFA) has comparable efficacy to conventional thermal ablation, but with important safety advantages: no esophageal injury or pulmonary vein stenosis, and rare phrenic nerve injury. However, when PFA is delivered in proximity to coronary arteries using a pentaspline catheter, which generates a broad electrical field, severe vasospasm can be provoked. OBJECTIVES: The authors sought to study the vasospastic potential of a focal PFA catheter with a narrower electrical field and develop a preventive strategy with nitroglycerin. METHODS: During atrial fibrillation ablation, a focal PFA catheter was used for cavotricuspid isthmus ablation. Angiography of the right coronary artery (some with fractional flow reserve measurement) was performed before, during, and after PFA. Beyond no nitroglycerin (n = 5), and a few testing strategies (n = 8), 2 primary nitroglycerin administration strategies were studied: 1) multiple boluses (3-2 mg every 2 min) into the right atrium (n = 10), and 2) a bolus (3 mg) into the right atrium with continuous peripheral intravenous infusion (1 mg/min; n = 10). RESULTS: Without nitroglycerin, cavotricuspid isthmus ablation provoked moderate-severe vasospasm in 4 of 5 (80%) patients (fractional flow reserve 0.71 ± 0.08). With repetitive nitroglycerin boluses, severe spasm did not occur, and mild-moderate vasospasm occurred in only 2 of 10 (20%). Using the bolus + infusion strategy, severe and mild-moderate spasm occurred in 1 and 3 of 10 patients (aggregate 40%). No patient had ST-segment changes. CONCLUSIONS: Ablation of the cavotricuspid isthmus using a focal PFA catheter routinely provokes right coronary vasospasm. Pretreatment with high doses of parenteral nitroglycerin prevents severe spasm.

A Randomized Trial of Electrographic Flow-Guided Redo Ablation for Nonparoxysmal Atrial Fibrillation (FLOW-AF).

BACKGROUND: Electrographic flow (EGF) mapping enables full spatiotemporal reconstruction of organized wavefront propagation to identify extrapulmonary vein sources of atrial fibrillation (AF). OBJECTIVES: FLOW-AF (A Randomized Controlled Study to Evaluate the Reliability of the Ablacon Electrographic FLOW [EGF] Algorithm Technology [Ablamap Software] to Identify AF Sources and Guide Ablation Therapy in Patients With Persistent Atrial Fibrillation) was multicenter, randomized controlled study of EGF mapping to: 1) stratify a nonparoxysmal AF population undergoing redo ablation; 2) guide ablation of these extrapulmonary vein AF sources; and 3) improve AF recurrence outcomes. METHODS: FLOW-AF enrolled persistent atrial fibrillation (PerAF)/long-standing PerAF patients undergoing redo ablation at 4 centers. One-minute EGF maps were recorded from standardized biatrial basket positions. Patients with source activity ≥26.5% were randomized 1:1 to PVI + EGF-guided ablation vs PVI only; patients without sources ≥26.5% threshold were not randomized. Follow-up and electrocardiographic monitoring occurred at 3, 6, and 12 months. RESULTS: We enrolled 85 patients (age 65.6 ± 9.3 years, 37% female, 24% long-standing PerAF). Thirty-four (40%) patients had no sources greater than threshold; at least 1 source greater than threshold was present in 46 (60%) (EGF-guided ablation, n = 22; control group, n = 26). Patients with sources were older (68.2 vs 62.6 years; P = 0.005) with higher CHA2DS2-VASc scores (2.8 vs 1.9; P = 0.001). The freedom from safety events was 97.2%, and 95% of EGF-identified sources were successfully ablated. In randomized patients, AF-free survival at 12 months was 68% for EGF-guided ablation vs 17% for the control group (P = 0.042); freedom from AF/atrial tachycardia/atrial flutter at 12 months was 51% vs 14% (P = 0.103), respectively. CONCLUSIONS: In nonparoxysmal AF patients undergoing redo ablation, EGF mapping identified AF sources in 60% of patients, and could be successfully ablated in 95%. Compared with PVI alone, PVI + source ablation improved AF-free survival by 51% on an absolute basis. (FLOW-AF: A Study to Evaluate the Ablacon Electrographic FLOW EGF Technology [A Randomized Controlled Study to Evaluate the Reliability of the Ablacon Electrographic FLOW (EGF) Algorithm Technology (Ablamap Software) to Identify AF Sources and Guide Ablation Therapy in Patients With Persistent Atrial Fibrillation]; NCT04473963).