Background: CLOSE-guided atrial fibrillation (AF) ablation is based on contiguous (intertag distance ≤6 mm), optimized (Ablation Index >550 anteriorly and >400 posteriorly) point-by-point radiofrequency lesions. The optimal radiofrequency power remains unknown. Methods: The POWER-AF study is a prospective, randomized controlled monocentric study including patients with paroxysmal AF, planned for first CLOSE-guided pulmonary vein isolation using a contact force radiofrequency catheter (Thermocool SmartTouch, Biosense Webster, Inc, Irvine, CA). A total of 100 patients were randomized into 2 groups (1:1). The control group received AF ablation using the standard CLOSE protocol (35 W), whereas in the experimental group, pulmonary vein isolation was performed using high power (45 W). Endoscopic evaluation was performed in patients with intraesophageal temperature rise >38.5 °C. Results: The resulting sample size was 96 (48+48) patients. In the high power group, shorter procedure time (80 versus 102 minutes, P <0.001), shorter total radiofrequency application time (16 versus 26 minutes, P <0.001), and radiofrequency time per application (26 versus 37 s anteriorly, P <0.001 and 13 versus 17 s posteriorly, P <0.001) were observed. Endoscopic evaluation (performed in 19/48 versus 25/48 patients respectively, P =0.31) showed an ulcerative perforation in a high power group patient (treated by endoscopic stenting and normalization after ≈4 months) and a superficial ulcerative lesion in a control group patient (conservative treatment). Both occurred following excessive Ablation Index applications (up to 460 and 480, respectively) with excessive contact force (30 g on average, with peaks up to 50 g). Six-months AF recurrence was not significantly different (10% in high power versus 8% in control, P =0.74). Conclusions: This randomized controlled study shows that a 45 W radiofrequency power CLOSE protocol in patients with paroxysmal AF significantly increases the global procedural efficiency with similar midterm efficacy. However, our study showed a narrower safety margin and a limited increased efficiency at the posterior wall using high power. This advocates against the use of high power in the region neighboring the esophagus.

Aims: Pulsed field ablation (PFA) is a growing ablation modality for pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients. This study assesses the 6-month safety and effectiveness of a novel balloon-in-basket, mapping-integrated PFA system, with a purpose-built form factor for PVI. Methods and results: The VOLT CE Mark Study is a prospective, multi-center, pre-market study. A total of 150 patients with drug-refractory paroxysmal (PAF) or persistent AF (PersAF) were enrolled between 8 November 2023 and 14 March 2024, of which 146 patients (age 64.1 ± 10.0 years, 63.0% male, 70.5% PAF) underwent PVI with the balloon-in-basket PFA catheter and system featuring integrated electroanatomic mapping with contact-sensing. Study endpoints were the rate of primary serious adverse events within 7 days as well as acute procedural effectiveness and 6-month freedom from recurrence. Acute effectiveness was achieved in 99.1% (573/578) of treated PVs (98.6% of patients, 144/146) with 17.6 ± 5.7 PFA applications/patient. Procedure, fluoroscopy, LA dwell, and transpired ablation times were 100.4 ± 33.0, 17.3 ± 12.1, 39.4 ± 20.6, and 31.4 ± 16.8 min, respectively. There were 4 (2.7%; 4/146) primary serious adverse events. The rate of freedom from documented atrial arrhythmias was 88.2% in PAF patients and 76.7% in PersAF patients (freedom from symptomatic recurrence was documented in 90.2% of PAF patients and 74.4% of PersAF patients) through 6-months post-index procedure. Conclusion: The VOLT CE Mark Study primary results demonstrate the safety and effectiveness of the novel balloon-in-basket PFA system to perform PVI in PAF and PersAF.

Objective: Pulmonary vein isolation (PVI) guided by a standardised CLOSE (contiguous optimised lesions) protocol has been shown to increase clinical success after catheter ablation for paroxysmal atrial fibrillation (PAF). This study analysed healthcare utilisation and quality of life (QOL) outcomes from a large multicentre prospective study, measured association between QOL and atrial fibrillation (AF) burden and identified factors associated with lack of QOL improvement.Methods: CLOSE-guided ablation was performed in 329 consecutive patients (age 61.4 years, 60.8% male) with drug-refractory PAF in 17 European centres. QOL was measured at baseline and 12 months post-ablation via Atrial Fibrillation Effect on QualiTy of Life Survey (AFEQT) and EuroQoL EQ-5D-5L questionnaires. All-cause and cardiovascular hospitalisations and cardioversions over 12 months pre-ablation and post-ablation were recorded. Rhythm monitoring included weekly and symptom-driven trans-telephonic monitoring, plus ECG and Holter monitoring at 3, 6 and 12 months. AF burden was defined as the percentage of postblanking tracings with an atrial tachyarrhythmia ≥30 s. Continuous measures across multiple time points were analysed using paired t-tests, and associations between various continuous measures were analysed using independent sample t-tests. Each statistical test used two-sided p values with a significance level of 0.05.Results: Both QOL instruments showed significant 12-month improvements across all domains: AFEQT score increased 25.1–37.5 points and 33.3%–50.8% fewer patients reporting any problem across EuroQoL EQ-5D-5L domains. Overall, AFEQT improvement was highly associated with AF burden (p=0.009 for <10% vs ≥10% burden, p<0.001 for <20% vs ≥20% burden). Cardiovascular hospitalisations were significantly decreased after ablation (42%, p=0.001). Patients without substantial improvement in AFEQT (55/301, 18.2%) had higher AFEQT and CHA₂DS₂-VASc scores at baseline, and higher AF burden following PVI.Conclusions: QOL improved and healthcare utilisation decreased significantly after ablation with a standardised CLOSE protocol. QOL improvement was significantly associated with impairment at baseline and AF burden after ablation.Trial registration number: NCT03062046.

Contact force (CF)–sensing radiofrequency (RF) catheters with an ablation index have shown reproducible outcomes for the treatment of atrial fibrillation (AF) in large multicentre studies. A dual-energy (DE) focal CF catheter to deliver RF and unipolar/biphasic pulsed field ablation (PFA), integrated with a three-dimensional (3D) mapping system, can provide operators with additional flexibility. The SmartfIRE study assessed the safety and efficacy of this novel technology for the treatment of drug-refractory, symptomatic paroxysmal AF. Results at 3 months post-ablation are presented here. Pulmonary vein isolation (PVI) was performed using a DE focal, irrigated CF-sensing catheter with the recommendation of PFA at posterior/inferior and RF ablation at the anterior/ridge/carina segments. Irrespective of energy, a tag size of 3 mm; an inter-tag distance ≤6 mm; a target index of 550 for anterior, roof, ridge, and carina; and a target index of 400 for posterior and inferior were recommended. Cavotricuspid isthmus ablation was permitted in patients with documented typical atrial flutter. The primary effectiveness endpoint was acute procedural success. The primary safety endpoint was the rate of primary adverse events (PAEs) within 7 days of the procedure. A prespecified patient subset underwent oesophageal endoscopy (EE; 72 h post-procedure), neurological assessment (NA; pre-procedure and discharge), and cardiac computed tomography (CT)/magnetic resonance angiogram (MRA) imaging (pre-procedure and 3 months post-procedure) for additional safety evaluation, and a mandatory remapping procedure (Day 75 ± 15) for PVI durability assessment. Of 149 patients enrolled between February and June 2023, 140 had the study catheter inserted (safety analysis set) and 137 had ablation energy delivered (per-protocol analysis set). The median (Q1/Q3) total procedure and fluoroscopy times were 108.0 (91.0/126.0) and 4.2 (2.3/7.7) min (n = 137). The acute procedural success rate was 100%. First-pass isolation was achieved in 89.1% of patients and 96.8% of veins. Cavotricuspid isthmus ablations were successfully performed in 12 patients [pulsed field (PF) only: 6, RF only: 5, and RF/PF: 1]. The PAE rate was 4.4% [6/137 patients; 2 pulmonary vein (PV) stenoses, 2 cardiac tamponades/perforations, 1 stroke, and 1 pericarditis]. No coronary artery spasm was reported. No oesophageal lesion was seen in the EE subset (0/31, 0%). In the NA subset (n = 30), microemboli lesions were identified in 2 patients (2/30, 6.7%), both of which were resolved at follow-up; only 1 was symptomatic (silent cerebral lesion, 3.3%). In the CT/MRA subset (n = 30), severe PV narrowing (of >70%) was detected in 2 patients (2/30, 6.7%; vein level 2/128, 1.6%), of whom 1 underwent dilatation and stenting and 1 was asymptomatic; both were associated with high index values and a small inter-tag distance. In the PV durability subset (n = 30), 100/115 treated PVs (87%) were durably isolated and 18/30 patients (60.0%) had all PVs durably isolated. A DE focal CF catheter with 3D mapping integration showed a 100% acute success rate with an acceptable safety profile in the treatment of paroxysmal AF. Prespecified 3-month remapping showed notable PVI durability. ClinicalTrials.gov Identifier: NCT05752487.

BACKGROUND: Macroreentry stands as the predominant mechanism of typical and atypical flutter. Despite advances in mapping, many aspects of macroreentrant atrial tachycardia remain unsolved. In this translational study, we applied principles of topology to understand the activation patterns, entrainment characteristics, and ablation responses in a large clinical macroreentrant atrial tachycardia database. METHODS: Because the atrium can be topologically seen as a closed sphere with holes, we used a computational fixed spherical mesh model with a finite number of holes to induce and analyze macroreentrant atrial tachycardia. The ensuing insights were used to interpret high-density activation maps, postpacing interval-tachycardia cycle length values (difference between postpacing interval and tachycardia cycle length), and ablation response in 131 cases of typical and atypical flutter (n=106 left atrium, n=25 right atrium). RESULTS: Modeling of macroreentrant atrial tachycardia revealed that reentry on closed surfaces consistently manifests itself as paired rotation and that an odd number of critical boundaries is mathematically impossible. Together with mathematical confirmation by the index theorem, this led to a unifying construct that could explain the number of loops, difference between postpacing interval and tachycardia cycle length values, and ablation outcomes (termination, no change, or prolongation in tachycardia cycle length) in all 131 cases. CONCLUSIONS: Combining topology with the index theorem offers a novel and cohesive framework for understanding and managing typical and atypical flutter.

Background and Aims: This trial compared single-procedure efficacy and safety of pulsed field ablation (PFA) vs radiofrequency ablation (RFA) in patients with drug-resistant paroxysmal atrial fibrillation (AF). Methods: BEAT PAROX-AF is a European, multicentre, open-label, randomized, controlled, superiority trial conducted across nine European sites. Eligible patients (aged 18–80 years) with symptomatic, drug-resistant paroxysmal AF were randomized (1:1) to either PFA (pentaspline) or RFA following the CLOSE protocol (contact force sensing catheter and electro-anatomical mapping system). The primary endpoint was the single-procedure success rate after 12 months defined as the absence of ≥30 s atrial arrhythmia recurrence, cardioversion, class I/III antiarrhythmic drug resumption after a 2-month blanking period, or any repeat ablation. Results: From December 2021 to January 2024, 292 patients were randomized and 289 (median age 63.5 years, 58% male) were analysed (PFA n = 145, RFA n = 144). Single-procedure success at 12 months was 112/145 (77.2%) in the PFA group and 111/143 (77.6%) in the RFA group (adjusted difference 0.9%; 95% confidence interval −8.2% to 10.1%; P = .84). Procedure-related serious adverse events occurred in 5 (3.4%) PFA vs 11 (7.6%) RFA patients (difference −3.3% [−8.4%, 1.8%]). No deaths, persistent phrenic palsy nor stroke occurred. In the RFA group, two patients had pulmonary vein stenosis >70% and 12 > 50%, two tamponades, and one oesophageal bleed. Conclusions: This randomized trial performed in patients with paroxysmal AF did not demonstrate superior efficacy of single-shot PFA vs point-by-point RFA using the CLOSE protocol regarding single-procedure freedom from atrial arrhythmias, despite fewer safety events being observed in this study with PFA.