Contact-force local impedance algorithm to guide effective pulmonary vein isolation in AF patients: 1-year outcome from an international multicenter clinical setting.

BACKGROUND: The combination of highly localized impedance (LI) and contact force (CF) may improve tissue characterization and lesion prediction during radiofrequency (RF) pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). OBJECTIVE: We report the outcomes of our acute and long-term clinical evaluation of CF-LI-guided PVI in consecutive AF ablation cases from an international multicenter clinical setting. METHODS: Three hundred twenty-four consecutive patients from 20 European centers undergoing RF catheter ablation with the Stablepoint™ catheter were enrolled in the CHARISMA registry. Of these, 275 had a minimum follow-up of 1 year and were included in the primary analysis. RESULTS: The mean procedure duration was 115 ± 47 min, and the mean fluoroscopy time was 9.9 ± 6 min. At the end of the procedures, all PVs had been successfully isolated in all study patients. Minor complications were reported in 12 patients (4.4%). At 1 year, 36 (13.1%) patients had had an AF recurrence, and freedom from antiarrhythmic drugs and AF recurrence was achieved in 228 (82.9%) patients. The recurrence rate was higher in patients with persistent AF (21/116, 18.1%) than in those with paroxysmal AF (15/159, 9.4%; p = 0.0459). On multivariate logistic analysis adjusted for baseline confounders, only time > 6 months from first diagnosis of AF to ablation (HR = 2.93, 95%CI 1.03 to 8.36, p = 0.0459) was independently associated with recurrences. CONCLUSION: An ablation strategy for PVI guided by CF-LI technology proved safe and effective and resulted in a low recurrence rate of AF over 1-year follow-up, irrespective of the underlying AF type. CLINICAL TRIAL REGISTRATION: Catheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice. (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998.

National workflow experience with pulsed field ablation for atrial fibrillation: learning curve, efficiency, and safety.

BACKGROUND: Recent data on pulsed field ablation (PFA) for atrial fibrillation (AF) ablation suggest a progressive reduction in procedural times. Real-world data regarding the relationship between the learning curve of PFA and clinical outcomes are scarce. The objective was to evaluate the PFA learning curve and its impact on acute outcomes. METHODS: Consecutive patients undergoing AF ablation with the FARAPULSE™ PFA system were included in a prospective, non-randomized multicenter study. Procedural times were stratified on the operators' learning curve. Comparative analysis of skin-to-skin time was conducted with radiofrequency (RF) and cryoablation (CB) pulmonary vein isolation (PVI) procedures performed by the same operators in the previous year. RESULTS: Among 752 patients, 35.1% were females, and 66.9% had paroxysmal AF; mean age was 62.2 ± 10 years. A total of 62.5% of procedures were performed by operators with > 20 PFA procedures. Both time to PVI (25.6 ± 10 min vs 16.5 ± 8, p < 0.0001) and fluoroscopy time (19.8 ± 8 min vs 15.9 ± 8 min, p = 0.0045) significantly improved after 10 associated with consistent linear trend towards procedural time reduction (R2 0.92-0.68 across various procedural metrics). Current PFA skin-to-skin time was lower than the historical skin-to-skin one in 217 (62.4%) procedures; it was similar in 112 (32.2%) cases and higher than the historical skin-to-skin one in 19 (5.5%). No major complications were reported. CONCLUSIONS: In this nationwide multicentric experience, the novel PFA system proved to be fast, safe, and acutely effective in both paroxysmal and persistent AF patients. The learning curve appears to be rapid, as improvements in procedural parameters were observed after only a few procedures. CLINICAL TRIAL REGISTRATION: Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA). URL: http://clinicaltrials.gov/ Identifier: NCT05617456.

Pulsed field ablation technology for pulmonary vein and left atrial posterior wall isolation in patients with persistent atrial fibrillation.

INTRODUCTION: Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation (PeAF) undergoing left atrial posterior wall isolation (LAPWI). METHODS: The Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA) prospective registry included consecutive patients referred for PeAF catheter ablation at 9 Italian centers, treated with the FARAPULSETM-PFA system. The primary efficacy and safety study endpoints were the acute LAPWI rate, freedom from arrhythmic recurrences and the incidence of major periprocedural complications. Patients undergoing pulmonary vein isolation (PVI) alone, PWI + LAPWI and redo procedures were compared. RESULTS: Among 249 patients, 21.7% had long-standing PeAF, 79.5% were male; mean age was 63 ± 9 years. LAPWI was performed in 57.6% of cases, with 15.3% being redo procedures. Median skin-to-skin times (PVI-only 68 [60-90] vs. PVI + LAPWI 70 [59-88] mins) did not differ between groups. 45.8% LAPWI cases were approached with a 3D-mapping system, and 37.3% with intracardiac echocardiography. LAPWI was achieved in all patients by means of PFA alone, in 88.8% cases at first pass. LAPWI was validated either by an Ultrahigh-density mapping system or by recording electrical activity + pacing maneuvers. No major complications occurred, while 2.4% minor complications were detected. During a median follow-up of 273 [191-379] days, 41 patients (16.5%) experienced an arrhythmic recurrence after the 90-day blanking period, with a mean time to recurrence of 223 ± 100 days and no differences among ablation strategies. CONCLUSION: LAPWI with PFA demonstrates feasibility, rapidity, and safety in real-world practice, offering a viable alternative for PeAF patients. LAPWI is achievable even with a fluoroscopy-only method and does not significantly extend overall procedural times.

Intracardiac echocardiography-guided pulsed-field ablation for successful ablation of atrial fibrillation: a propensity-matched analysis from a large nationwide multicenter experience.

BACKGROUND: Intracardiac echocardiography (ICE) is increasingly employed in atrial fibrillation (AF) ablation procedures, with the potential to enhance procedural efficacy. Nevertheless, there is currently a lack of evidence assessing the impact of ICE on the efficiency, effectiveness, and safety outcomes in the context of novel pulsed-field ablation (PFA) for AF. PURPOSE: We aimed to assess whether the use of ICE could improve procedural parameters in a large population undergoing AF ablation with FARAPULSE™ catheter. METHODS: Consecutive patients who had undergone PFA of AF from nine Italian centers were included. In procedures where the ICE catheter was employed for guidance (ICE-guided group), it was used to maneuver the PFA catheter within the left atrium to achieve optimal contact with atrial structures. RESULTS: We analyzed 556 patients: 357 (66%) with paroxysmal AF, 499 (89.7%) de novo PVI. ICE-guided procedures (n = 138) were propensity matched with patients with a standard approach (n = 138), and their outcomes were compared. During ICE-guided procedures, no improvement in procedural metrics was recorded (ICE vs Standard, 23 ± 6 min vs 18.5 ± 9 min for time to PVI, p < 0.0001; 38.8 ± 7 vs 32.5 ± 5 number of PFA deliveries to achieve PVI, p < 0.0001; 68.8 ± 19 min vs 71.8 ± 29 min for primary operator time, p = 0.5301; 16.1 ± 8 min vs 18.2 ± 10 min for fluoroscopy time, p = 0.5476) except for support time (76.8 ± 26 min vs 91.4 ± 37 min, p = 0.0046). No major procedure-related adverse events were reported. CONCLUSION: Our findings confirmed that PFA could be consistently performed in a rapid, safe, and efficacious manner. The use of ICE to guide PFA was not associated with an improvement in procedural metrics.

Insight into contact force local impedance technology for predicting effective pulmonary vein isolation.

Background: Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have the potential to act as a reliable predictor of the durability of the lesions created. Objective: We aimed to collect data on the procedural parameters affecting LI-guided ablation in a large multicenter registry. Methods: A total of 212 consecutive patients enrolled in the CHARISMA registry and undergoing their first pulmonary vein (PV) isolation for paroxysmal and persistent AF were included. Results: In all, 13,891 radiofrequency (RF) applications of ≥3 s duration were assessed. The first-pass PV isolation rate was 93.3%. A total of 80 PV gaps were detected. At successful ablation spots, baseline LI and absolute LI drop were larger than at PV gap spots (161.4 ± 19â€…Ω vs. 153.0 ± 13 Ω, p < 0.0001 for baseline LI; 22.1 ± 9â€…Ω vs. 14.4 ± 5 Ω, p < 0.0001 for LI drop). On the basis of Receiver operating characteristic curve analysis, the ideal LI drop, which predicted successful ablation, was >21â€…Ω at anterior sites and >18â€…Ω at posterior sites. There was a non-linear association between the magnitude of LI drop and contact-force (CF) (r = 0.14, 95% CI: 0.13-0.16, p < 0.0001) whereas both CF and LI drop were inversely related with delivery time (DT) (-0.22, -0.23 to -0.20, p < 0.0001 for CF; -0.27, -0.29 to -0.26, p < 0.0001 for LI drop). Conclusion: An LI drop >21â€…Ω at anterior sites and >18â€…Ω at posterior sites predicts successful ablation. A higher CF was associated with an increased likelihood of ideal LI drop. The combination of good CF and adequate LI drop allows a significant reduction in RF DT. Clinical trial registration: http://clinicaltrials.gov/, identifier: NCT03793998.

Ultra-high-resolution assessment of lesion extension after cryoballoon ablation for pulmonary vein isolation.

Introduction: Unrecognized incomplete pulmonary vein (PV) isolation during the index procedure, can be a major cause of clinical recurrences of atrial fibrillation (AF) after cryoballoon (CB) ablation. We aimed to characterize the extension of the lesions produced by CB ablation and to assess the value of using an ultra-high resolution electroanatomic mapping (UHDM) system to detect incomplete CB lesions. Materials and methods: Twenty-nine consecutive patients from the CHARISMA registry undergoing AF ablation at four Italian centers were prospectively evaluated. The Rhythmia™ mapping system and the Orion™ (Boston Scientific) mapping catheter were used to systematically map the left atrium and PVs before and after cryoablation. Results: A total of 116 PVs were targeted and isolated. Quantitative assessment of the lesions revealed a significant reduction of the antral surface area of the PV, resulting in an ablated area of 5.7 ± 0.7 cm2 and 5.1 ± 0.8 cm2 for the left PV pair and right PV pair, respectively (p = 0.0068). The mean posterior wall (PW) area was 22.9 ± 2 cm2 and, following PV isolation, 44.8 ± 6% of the PW area was ablated. After CB ablation, complete isolation of each PV was documented by the POLARMap™ catheter in all patients. By contrast, confirmatory UHDM and the Lumipoint™ tool unveiled PV signals in 1 out of 114 of the PVs (0.9%). Over 30-day follow-up, no major procedure-related adverse events were reported. After a mean follow-up of 333 days, 89.7% of patients were free from arrhythmia recurrence. Conclusion: The lesion extension achieved by the new CB ablation system involved the PV antrum, with less than 50% of the PW remaining untouched. The new system, with short tip and circular mapping catheter, failed to achieve PV isolation in only 0.9% of all PVs treated. Clinical trial registration: [http://clinicaltrials.gov/], identifier [NCT03793998].

Improved procedural workflow for catheter ablation of paroxysmal AF with high-density mapping system and advanced technology: Rationale and study design of a multicenter international study.

BACKGROUND: The antral region of pulmonary veins (PV)s seems to play a key role in a strategy aimed at preventing atrial fibrillation (AF) recurrence. Particularly, low-voltage activity in tissue such as the PV antra and residual potential within the antral scar likely represent vulnerabilities in antral lesion sets, and ablation of these targets seems to improve freedom from AF. The aim of this study is to validate a structured application of an approach that includes the complete abolition of any antral potential achieving electrical quiescence in antral regions. METHODS: The improveD procEdural workfLow for cathETEr ablation of paroxysmal AF with high density mapping system and advanced technology (DELETE AF) study is a prospective, single-arm, international post-market cohort study designed to demonstrate a low rate of clinical atrial arrhythmias recurrence with an improved procedural workflow for catheter ablation of paroxysmal AF, using the most advanced point-by-point RF ablation technology in a multicenter setting. About 300 consecutive patients with standard indications for AF ablation will be enrolled in this study. Post-ablation, all patients will be monitored with ambulatory event monitoring, starting within 30 days post-ablation to proactively detect and manage any recurrences within the 90-day blanking period, as well as Holter monitoring at 3, 6, 9, and 12 months post-ablation. Healthcare resource utilization, clinical data, complications, patients' medical complaints related to the ablation procedure and patient's reported outcome measures will be prospectively traced and evaluated. DISCUSSION: The DELETE AF trial will provide additional knowledge on long-term outcome following a structured ablation workflow, with high density mapping, advanced algorithms and local impedance technology, in an international multicentric fashion. DELETE AF is registered at ClinicalTrials.gov (NCT05005143).

When local impedance meets contact force: preliminary experience from the CHARISMA registry.

PURPOSE: Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have emerged as a viable real-time indicator of tissue characteristics and the consequent durability of the lesions created. We investigated the impact of catheter-tissue contact force (CF) on LI behavior during pulmonary vein isolation (PVI). METHODS: Forty-five consecutive patients of the CHARISMA registry undergoing de novo AF radiofrequency (RF) catheter ablation with a novel open-irrigated-tip catheter endowed with CF and LI measurement capabilities (Stablepoint™ catheter, Boston Scientific) were included. RESULTS: A total of 2895 point-by-point RF applications were analyzed (RF delivery time (DT) = 8.7±4s, CF = 13 ±±8 g, LI drop = 23 ±±7 Ω). All PVs were successfully isolated in an overall procedure time of 118 ±±34 min (fluoroscopy time = 13 ±±8 min). The magnitude of LI drop weakly correlated with CF (r = 0.13, 95% confidence interval (CI): 0.09 to 0.16, p < 0.0001), whereas both CF and LI drop inversely correlated with DT (r = -0.26, 95%CI: -0.29 to -0.22, p < 0.0001 for CF; r = -0.36, 95%CI: -0.39 to -0.33, p < 0.0001 for LI). For each 10 g of CF, LI drop markedly increased from 22.4 ± 7 Ω to 24.0 ± 8 Ω at 5 to 25 g CF intervals (5-14 g of CF vs 15-24 g of CF, p < 0.0001), whereas it showed smooth transition over 25 g (24.8 ± 7Ω at ≥ 25 g CF intervals, p = 0.0606 vs 15-24 g of CF). No major complications occurred during the procedures or within 30 days. CONCLUSIONS: CF significantly affects LI drop and probable consequent lesion formation during RF PVI. The benefit of higher contact (> 25 g) between the catheter and the tissue appears to have less impact on LI drop. TRIAL REGISTRATION: Catheter Ablation of Arrhythmias With High Density Mapping System in the Real World Practice (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998.