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Background: The optimal radiofrequency application (RFa) parameters for safe and durable pulmonary vein isolation (PVI) are debated. High-power short-duration (HPSD) has been used as an alternative to conventional power delivery (CPD)., Objectives: This study sought to compare HPSD 70 W/9-10 s (HPSD-70) with CPD 25-40 W in patients undergoing PVI., Methods: Patients were randomized to HPSD-70 or CPD (25-40). The primary outcomes were freedom from atrial arrhythmia recurrences and the incidence of esophageal thermal lesions (EDELs) after ablation., Results: Among 304 patients randomized, 301 remained in the study (median age: 61 years; Q1-Q3: 53-69 years; 72% men): 294 patients (97.7%) underwent ablation, 285 (94.7%) underwent endoscopy, and 290 (98.6%) completed the follow-up. At 12 months, 100 patients (73.5%) in the CPD (25-40) group and 87 patients (67%) in the HPSD-70 group were free from recurrences off antiarrhythmic drugs (HR: 1.28; 95% CI: 0.82-1.99; P = 0.28). The incidences of EDELs were 2.7% in the CPD (25-40) group and 3.6% in the HPSD-70 group (P = 0.94). Median left atrial dwell (153 vs 137 min; P = 0.03) and total RF times for definitive PVI (31 vs 11.2 min; P < 0.001) were shorter with HPSD-70 ablation. Four symptomatic embolic events (2 strokes, 1 transient ischemic attack, and 1 splenic infarct) occurred with HPSD-70 and none with CPD (25-40) RFa (P = 0.056)., Conclusions: HPSD-70 RFa was noninferior to prevent arrhythmia recurrences, and the incidence of EDELs was similar compared with CPD (25-40) RFa. The embolic events were numerically higher in the HPSD-70 group. (High Radiofrequency Power for Faster and Safer Pulmonary Vein Ablation Trial [POWER FAST III]; NCT04153747)., Competing Interests: Funding Support and Author Disclosures This clinical trial was funded by the Spanish Society of Cardiology (SEC-BAYER Projects for Clinical Investigation in Cardiology 2018) and the Carlos III Health Institute (PI18/01522, Spanish Health Research and Development Strategy). These funding institutions had no role in the design of the study and had no role during its execution, analyses, interpretation of the data, or decision to submit results for publication. Dr Castrejón-Castrejón has received fees and honoraria for lectures, education, and scientific advice from Abbott, Biosense-Webster, Microport, and Smart Solutions Technologies. Dr Roca-Luque has received consultant and speaker honoraria for Abbott Medical and Biosense-Webster. Dr Quesada has received consulting and research support from Abbott. Dr Merino has received fees and honoraria for lectures, education, and scientific advice from Abbott, Biosense-Webster, Biotronik, iRhythm Technologies, Microport, and Zoll. All other authors have no relationships relevant to the contents of this paper to disclose., (Copyright © 2025 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Myocardium baseline impedance (BI) is an important factor in ablation effectiveness. This study examined the performance of low-power and long-duration (LPLD), high-power and short-duration (HPSD) ablation at different BIs by computer simulation. A 3D model of the ablation region was constructed for simulation, and in vitro experiments were performed to validate the simulation. Three ablation power and duration configurations of 30 W/30 s, 50 W/10 s, and 90 W/5 s were used for simulation with BI values of 90, 100, 110, 120, 130, and 140 Ω. Roll-off time and ablation volume were measured to evaluate ablation results. The simulation is consistent with the in vitro experiments. When BI is changed from 90 [Formula: see text] to 140 [Formula: see text], the lesion volume over 50 °C with BI of 140 [Formula: see text] was reduced by 6.3%, 6.7%, and 7.3% for 30 W/30 s, 50 W/10 s, and 90 W/5 s configurations, respectively, and the lesion volume over 100 °C was reduced by 62.8%, 49.7%, and 22.5% under 30 W/30 s, 50 W/10 s, and 90 W/5 s, respectively. Simulation results revealed that HPSD (vHPSD) and LPLD ablation were more affected by changes in BI in the lesion volumes over 50 °C and 100 °C, respectively, and demonstrated that resistive and conductive heating were the main heating effects in HPSD (vHPSD) and LPLD, respectively., (© 2023. Springer Nature Japan KK, part of Springer Nature.)

Aims: The optimal interlesion distance (ILD) for 90 and 50 W radiofrequency applications with low ablation index (AI) values in the atria has not been established. Excessive ILDs can predispose to interlesion gaps, whereas restrictive ILDs can predispose to procedural complications. The present study sought, therefore, to experimentally determine the optimal ILD for 90 W-4 s and 50 W applications with low AI values to optimize catheter ablation outcomes in humans., Methods and Results: Posterior intercaval lines were created in eight adult sheep using CARTO and the QDOT-MICRO catheter in a temperature-controlled mode. In four animals, the lines were created with 50 W applications, a target AI value ≥350, and ILDs of 6, 5, 4, and 3 mm, respectively. In the other four animals, the lines were created with 90 W-4 s applications and ILDs of 6, 5, 4, and 3 mm, respectively. Activation maps were created immediately after ablation and at 21 days to assess linear block prior to gross and histological analyses. All eight lines appeared transmural and continuous on histology. However, for 50 W-only applications with an ILD of 3 mm resulted in durable linear electrical block, whereas for 90 W applications, only the lines with ILDs of 4 and 3 mm were blocked. No complications were detected during ablation procedures, but all power and ILD combinations except 50 W-6 mm resulted in asymptomatic shallow lung lesions., Conclusion: In the intercaval region in sheep, for 50 W applications with an AI value of ∼370, the optimal ILD is 3 mm, whereas for 90 W-4 s applications, the optimal ILD is 3-4 mm., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: The long-term efficacy of high-power (50 W) ablation guided by lesion size index (LSI-guided HP) for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) remains undetermined. Our study sought to assess the clinical efficacy of LSI-guided HP ablation for PVI in patients with AF and explore the potential predictors associated with clinical outcomes., Methods: We consecutively included 186 patients with AF who underwent LSI-guided HP (50 W) ablation at Fuwai Hospital from June 2019 to October 2021. The target LSI values of 4.5-5.5 and 4.0-4.5 at the anterior and posterior walls, respectively, were used in our study. The baseline clinical characteristics, procedural and ablation data, and clinical outcomes were evaluated. The independent potential predictors associated with AF recurrence were further evaluated., Results: The incidence rate of first-pass PVI was 83.9% (156/186). A total of 11 883 lesions were analyzed, and compared with posterior walls of pulmonary veins, anterior walls had significantly lower mean contact force (8.2 ± 3.0 vs. 8.3 ± 2.3 g, p = .015), longer mean radiofrequency duration (16.9 ± 7.2 vs. 12.9 ± 4.5 s, p < .001) and higher mean LSI (4.8 ± 0.2 vs. 4.4 ± 0.2, p < .001). The overall incidence of periprocedural complications was 3.7%, and steam pops without pericardial effusion occurred in three patients (1.6%). During a mean follow-up of 24.0 ± 8.4 months, the overall AF recurrence-free survival was 87.1% after a single procedure. Patients with paroxysmal AF had a higher incidence of freedom from AF recurrence than those with persistent AF (91.2% vs. 80.8%, log-rank p = .034). Higher LSI (HR 0.50, p < .001) and paroxysmal AF (HR 0.39, p = .029) were significantly associated with decreased AF recurrence. By receiver operating characteristic analysis, the LSI of 4.7 and 4.3 for the anterior and posterior walls of the PVs had the highest predictive value for AF recurrence, respectively., Conclusion: LSI-guided HP (50 W) ablation for PVI was an efficient and safe strategy and led to favorable single-procedure 2-year AF recurrence-free survival in patients with AF. Higher LSI and paroxysmal AF were independent predictors of decreased 2-year AF recurrence. The LSI of 4.7 for the anterior wall and 4.3 for the posterior wall of the PVs were the best cutoff values for predicting AF recurrence after LSI-guided HP ablation., (© 2023 Wiley Periodicals LLC.)

Background: The high power short duration (HPSD) approach was hoped to further improve the efficacy and safety in radiofrequency ablation of atrial fibrillation (AF), compared with Low power long duration (LPLD). However, the conclusion was controversial based on the previous limited data. The aim of this meta-analysis was to evaluate whether the clinical benefits of HPSD are superior to that of LPLD., Methods: The PubMed, OVID, the Cochrane Library, and Elsevier's ScienceDirect databases were searched for clinical studies to compare HPSD and LPLD approach by simple search strings benefiting to a wider screened scope., Results: Fifteen trials with 3255 patients were included in this analysis. Pooled analyses suggested that HPSD was associated with a lower recurrence of atrial tachyarrhythmias (ATAs) at 1-year follow-up (OR: 0.49; 95% CI: 0.35 to 0.67, p  < .0001), benefitted from AF recurrence reduced (OR: 0.46; 95% CI: 0.31 to 0.67, p  < .0001), rather than atrial tachycardia/atrial flutter (AT/AFL), but similar at 6 months follow-up, with a decreased oesophageal thermal injury (ETI) (OR: 0.48; 95% CI: 0.30 to 0.77, p  = .002). Meanwhile, the HPSD approach benefitted to increase first-pass pulmonary vein isolation (FPI) (OR: 0.47; 95% CI: 0.34 to 0.64, p  < .00001) and decrease acute pulmonary vein re-isolation (PVR) (OR: 0.45; 95% CI: 0.35 to 0.58, p  < .00001), both mainly embodied in left pulmonary veins (PVs). HPSD showed a decreased procedural time (SMD: -0.95; 95% CI: -1.06 to -0.85, p  < .00001), ablation number for pulmonary vein isolation (PVI) (SMD: -0.41; 95% CI: -0.58 to -0.24, p  < .00001) and fluoroscopy time (SMD: -0.22; 95% CI: -0.32 to -0.12, p  < .0001), which benefits from PVI + additional ablation strategy (SMD: -0.33; 95% CI: -0.46 to -0.21, p  < .0001)., Conclusions: The HPSD approach was associated with decreasing post-ablation AF recurrence in the 1-year follow-up, ETI, acute PVR (increasing FPI correspondingly), procedural time, ablation number for PVI and fluoroscopy time, benefitted to improve clinical outcomes and procedural process with improved safety.

Background: Contact force-sensing catheters have been widely used in catheter ablation. During the past few decades, more attention has been paid on the technique of high-power ablation. The purpose of this meta-analysis is to compare the efficacy and safety of conventional power and high power on atrial fibrillation radiofrequency ablation by contact force-sensing catheters., Methods: We identified studies through searching MEDLINE, Embase, the Web of Science, Scopus, and the Cochrane Library from inception up until July 2020. The primary outcomes were defined as recurrence of atrial tachyarrhythmia and complications. The secondary outcomes were acute reconnections of pulmonary veins (PVs), ablation time, and the total procedural time., Results: Four nonrandomized, observational studies (nROS) were selected involving 231 patients with high-power ablation and 239 patients with conventional power ablation. There were insignificant differences in the recurrence rate of atrial tachyarrhythmia (14.2% versus 20.5%, OR: 0.64, 95%CI: 0.39 to 1.04, Z = 1.82, P = 0.07) and clinical complications (1.7% versus 2.5%, OR: 0.72, 95%CI: 0.21 to 2.47, Z = 0.51, P = 0.61) between high-power and conventional power ablation. However, compared with conventional power group, the high-power group had fewer acute PVs reconnections (P = 0.0001), shorter in ablation time (P < 0.0001), and the total procedural time (P < 0.0001)., Conclusions: High-power ablation could not only ablate safely and efficiently but also reduce focal ablation time and total procedural time significantly., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Many centers use radiofrequency (RF) energy at 25-35 W for 30-60 seconds. There is a safety concern about using higher power, especially on the posterior wall., Objective: The purpose of this study was to examine complication rates for atrial fibrillation (AF) ablations performed with high-power, short-duration RF energy., Methods: We examined the complication rates of 4 experienced centers performing AF ablations at RF powers from 45-50 W for 2-15 seconds per lesion. In total, 13,974 ablations were performed in 10,284 patients. On the posterior wall, 11,436 ablations used 45-50 W for 2-10 seconds, and 2538 ablations used power reduced to 35 W for 20 seconds. Esophageal temperature monitoring was used in 13,858 (99.2%)., Results: Demographics were age 64 ± 11 years, male 68%, left atrial size 4.4 ± 0.7 cm, paroxysmal AF 37%, persistent AF 42%, longstanding AF 20%, antiarrhythmic drugs failed 1.4 ± 0.7, hypertension 54%, diabetes 15%, previous cerebrovascular accident/transient ischemic attack 7%, and CHA 2 DS 2 -VASc score 2.1 ± 1.4. Procedural time was 116 ± 41 minutes. Complications were death in 2 (0.014%; 1 due to stroke and 1 due to atrioesophageal fistula), pericardial tamponade in 33 (0.24%; 26 tapped, 7 surgical), strokes <48 hours in 6 (0.043%), strokes 48 hours-30 days in 6 (0.043%), pulmonary vein stenosis requiring intervention in 2 (0.014%), phrenic nerve paralysis in 2 (0.014%; both resolved), steam pops 2 (0.014%) without complications, and catheter char 0 (0.00%). There was 1 atrioesophageal fistula in 11,436 ablations using power 45-50 W on the posterior wall and 3 in 2538 ablated with 35 W on the posterior wall (P = .021), although 2 of the 3 had no esophageal monitoring during a fluoroless procedure., Conclusion: AF ablations can be performed at 45-50 W for short durations with very low complication rates. High-power, short-duration ablations have the potential to shorten procedural and total RF times and create more localized and durable lesions., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Abstract Objective High‐power ablation has been widely used in atrial fibrillation (AF). However, there were many studies observed the outcomes of the short‐term follow‐up. This study aims to the long‐term results of high‐power ablation guided by ablation index (AI) in patients with AF. Methods Analysis of patients with AF, who first received high‐power (40–50 W) ablation, to pulmonary vein isolation (PVI) in the Second Hospital of Shanxi Medical University from May 2020 to March 2022. All patients were managed perioperatively according to the routine treatment procedures. High‐power ablation was conducted under the guidance of our conventional power AI and baseline data, first‐pass PVI rate, ablation time, operative time, and long‐term surgical success rate were analyzed. Results A total of 83 patients with atrial fibrillation were enrolled in the study, with an average age of 61.62 ± 9.04 years, 47 male patients, and 49 paroxysmal atrial fibrillation. All patients achieved PVI, and the rate of first pass was 82%. The ablation time of the left atrial was 28.54 ± 9.11 min. There were no serious complications related to ablation, and only a small amount of pericardial effusion was found in 4 patients. During the follow‐up period of 26.36 ± 6.11 months, 8 patients were lost to follow‐up and the overall success rate was 84%, including 91% for paroxysmal AF and 71% for persistent AF. Conclusion High‐power ablation long‐term results appear a high freedom atrial arrhythmia, but further expanded samples are needed for controlled studies.

Aims The optimal interlesion distance (ILD) for 90 and 50 W radiofrequency applications with low ablation index (AI) values in the atria has not been established. Excessive ILDs can predispose to interlesion gaps, whereas restrictive ILDs can predispose to procedural complications. The present study sought, therefore, to experimentally determine the optimal ILD for 90 W–4 s and 50 W applications with low AI values to optimize catheter ablation outcomes in humans. Methods and results Posterior intercaval lines were created in eight adult sheep using CARTO and the QDOT-MICRO catheter in a temperature-controlled mode. In four animals, the lines were created with 50 W applications, a target AI value ≥350, and ILDs of 6, 5, 4, and 3 mm, respectively. In the other four animals, the lines were created with 90 W–4 s applications and ILDs of 6, 5, 4, and 3 mm, respectively. Activation maps were created immediately after ablation and at 21 days to assess linear block prior to gross and histological analyses. All eight lines appeared transmural and continuous on histology. However, for 50 W-only applications with an ILD of 3 mm resulted in durable linear electrical block, whereas for 90 W applications, only the lines with ILDs of 4 and 3 mm were blocked. No complications were detected during ablation procedures, but all power and ILD combinations except 50 W–6 mm resulted in asymptomatic shallow lung lesions. Conclusion In the intercaval region in sheep, for 50 W applications with an AI value of ∼370, the optimal ILD is 3 mm, whereas for 90 W–4 s applications, the optimal ILD is 3–4 mm. [ABSTRACT FROM AUTHOR]

Background: High-power, short-duration (HPSD) radiofrequency ablation (RFA) may reduce ablation time. Concerns that catheter-mounted thermocouples (TCs) can underestimate tissue temperature, resulting in elevated risk of steam pop formation, potentially limit widespread adoption of HPSD ablation. Objective: The purpose of this study was to compare the safety and efficacy of HPSD and low-power, long-duration (LPLD) RFA in the context of pulmonary vein isolation (PVI). Methods: An open-irrigated ablation catheter with a contact force sensor and a flexible-tip electrode containing a TC at its distal end (TactiFlexTM Ablation Catheter, Sensor EnabledTM, Abbott) was used to isolate the left pulmonary veins (PVs) in 12 canines with HPSD RFA (50 W for 10 seconds) and LPLD RFA (30 W for a maximum of 60 seconds). PVI was assessed at 30 minutes and 28 ± 3 days postablation. Computed tomographic scans were performed to assess PV stenosis after RFA. Lesions were evaluated with histopathology. Results: A total of 545 ablations were delivered: 252 with LPLD (0 steam pops) and 293 with HPSD RFA (2 steam pops) (P = .501). Ablation time required to achieve PVI was >3-fold shorter for HPSD than for LPLD RFA (P = .001). All 24 PVs were isolated 30 minutes after ablation, with 12/12 LPLD-ablated and 11/12 HPSD-ablated PVs still isolated at follow-up. Histopathology revealed transmural ablations for HPSD and LPLD RFA. No major adverse events occurred. Conclusion: An investigational ablation catheter effectively delivered RFA lesions. Ablation time required to achieve PVI with HPSD with this catheter was >3-fold shorter than with LPLD RFA.

Objective: The purpose of this study was to evaluate the difference in effectiveness and safety of high-power, short-duration (HPSD) radiofrequency catheter ablation (RFA) guided by relatively low ablation index (AI) values and conventional RFA in paroxysmal atrial fibrillation (PAF) patients. Methods: The HPSD RFA strategy (40–50 W, AI 350–400 for anterior, 320–350 for posterior wall; n = 547) was compared with the conventional RFA strategy (25–40 W, without AI; n = 396) in PAF patients who underwent their first ablation. Propensity-score matching analyses were used to compare the outcomes of the two groups while controlling for confounders. Results: After using propensity-score matching analysis, the HPSD group showed a higher early recurrence rate (22.727% vs. 13.636%, p = 0.003), similar late recurrence rate, and comparable safety (p = 0.604) compared with the conventional group. For late recurrent atrial arrhythmia types, the rate of regular atrial tachycardia was significantly higher in the HPSD group (p = 0.013). Additionally, the rate of chronic pulmonary vein reconnection and non-pulmonary vein triggers during repeat procedures was similar in both groups. Conclusions: For PAF patients, compared with the conventional RFA strategy, the HPSD RFA strategy at relatively low AI settings had a higher early recurrence rate, similar long-term success rate, and comparable safety. [ABSTRACT FROM AUTHOR]

Background: For patients with persistent atrial fibrillation (AF), whether linear ablation should be performed remains controversial, and the efficacy and safety for ablation index (AI)-guided high-energy linear ablation of mitral isthmus (MI) and left atrial (LA) posterior box isolation is still unclear. The aims of this study were to assess the feasibility and clinical success rate of pulmonary veins isolation (PVI) combined with linear ablation of LA roof and posterior inferior (posterior wall isolation) and MI compare with the PVI-alone method in patients of persistent AF. Methods and results: 362 consecutive persistent AF patients were enrolled from two electrophysiology centers. A total of 200 cases were in PVI-plus group and 162 cases were in PVI-alone group. The PVI-alone group received wide circumferential isolation of both ipsilateral pulmonary veins. PVI combined with linear ablation of left atrial posterior wall isolation (LAPWI)and MI were performed in the PVI-plus group. The primary study end point was the first recurrence of an atrial arrhythmia. After 24 months, freedom from the primary endpoint was achieved in 73.5% of the patients in the PVI-plus group and 62.5% in the PVI-alone group (hazard ratio = 0.62, 95% confidence interval: 0.43–0.91, log rank p = 0.012). The procedure-related complication rates were 2.5% in PVI-plus group and 1.9% in PVI-alone group (p = 0.808). Conclusion: In this study, the ablation strategy of ablation (PVI plus linear ablation of mitral isthmus and posterior box isolation) was feasible and safe for persistent AF patients. Compared with the PVI-alone method, it improved outcomes in patients with persistent AF. [ABSTRACT FROM AUTHOR]

Abstract Background When performing an electrical isolation of ipsilateral pulmonary veins (PVs) for atrial fibrillation, physicians often need additional radiofrequency (RF) ablation in the carina region between the superior and inferior PVs to achieve a right PV isolation because of intercaval bundles between the right PVs and right atrium (RA). We compared the efficacy of a high‐power and short‐duration ablation guided by unipolar signal modification (UM) with the conventional method (CM) for ablating epicardial connections between the right PV carina and RA. Methods The study subjects consisted of patients who underwent an initial box isolation of atrial fibrillation from January 2015 to December 2019 at Nara Medical University Hospital. Among these patients, 94 and 65 patients who met the criteria were assigned to the CM and UM groups, respectively. We retrospectively analyzed the anterior ablation line of the right PV using an electroanatomical mapping system. Patients whose initial ablation line included the right PV carina were excluded. Results Six and seven patients were, respectively, excluded from the CM and UM groups. Among 88 CM group patients, 21 needed additional right PV carina ablation, while among 58 UM group patients, 30 needed additional right PV carina ablation (p = .001). No anatomical factors were associated with the additional right PV carina ablation. Conclusions Compared to the CM group, a box isolation was less achievable without RF ablation at the right PV carina in the UM group. We should consider a long‐duration ablation for epicardial connections between the right PV carina and RA.

AimTo compare high-power (HP) vs. conventional-power (CP) radiofrequency ablation for atrial fibrillation (AF).MethodsWe retrospectively enrolled AF patients undergoing CP (30–40 W, 43 patients) or HP (50 W, 49 patients) radiofrequency ablation. Immediate pulmonary vein (PV) single-circle isolation, PV-ablation time, AF recurrence, AF recurrence-free survival, and complications were analyzed.ResultsDiabetes was more common in the CP group than in the HP group (27.91% vs. 10.20%, P = 0.029). The left PV single-circle isolation rate (62.79% vs. 65.31%), right PV single-circle isolation rate (48.84% vs. 53.06%), and bilateral PV single-circle isolation rate (32.56% vs. 38.78%; all P > 0.05) did not differ between the groups. Single-circle ablation times for the left PVs (12.79 ± 3.39 vs. 22.94 ± 6.39 min), right PVs (12.18 ± 3.46 vs. 20.67 ± 5.44 min), and all PVs (25.85 ± 6.04 vs. 45.66 ± 11.11 min; all P < 0.001) were shorter in the HP group. Atrial fibrillation recurrence within 3 months (13.95% vs. 18.37%), at 3 months (11.63% vs. 8.16%), and at 6 months after ablation (18.60% vs. 12.24%; all P > 0.05) was similar in both groups. Atrial fibrillation recurrence-free survival did not differ between the groups (Kaplan-Meier analysis). Cardiac rupture and pericardial tamponade did not occur in any patient. Pops occurred in 2 and 0 patients in the HP and CP groups, respectively (4.08% vs. 0.00%, P = 0.533).ConclusionHigh-power ablation improved operation time and efficiency without increasing complications.

Atrial fibrillation is the most common presentation in adult patients with cor triatriatum sinister. The key to successful and safe catheter ablation in these patients is an accurate exploration and thorough understanding of the left atrial anatomy, both before and during the procedure. Catheter manipulation is highly dependable on left atrial anatomy, including the interatrial septum, insertion of pulmonary veins and cor triatriatum membrane. Anatomical variants such as the left common pulmonary trunk may influence the ablation approach and outcome. We report the case of a 52-year-old patient with cor triatriatum sinister and the left common pulmonary vein variant who underwent successful high-power, short-duration catheter ablation for paroxysmal atrial fibrillation. [ABSTRACT FROM AUTHOR]

Abstract Background It has been demonstrated that a high‐power, short‐duration (HPSD) ablation during pulmonary vein (PV) isolation is effective and safe. However, studies about the HPSD ablation during the posterior wall isolation, the Box isolation (BOXI), are limited. We evaluated the efficacy, feasibility, and safety of HPSD ablation during BOXI. Methods One‐hundred sixty patients with all types of atrial fibrillation underwent BOXI with HPSD ablation (n = 80) or conventional technique (n = 80). In the HPSD group, ablation was performed with 50 W and a target lesion size index of 5.0 using a contact force (CF) sensing catheter. Ablation near the esophagus was performed with 50 W for 5 seconds and a CF

BackgroundAlthough both high-power (HP) ablation and lesion size index (LSI) are novel approaches to make effective lesions during pulmonary vein isolation (PVI) for atrial fibrillation (AF), the optimal LSI in HP ablation for PVI is still unclear. Our study sought to explore the association between LSI and acute conduction gap formation and investigate the optimal LSI in HP ablation for PVI.MethodsA total of 105 consecutive patients with AF who underwent HP ablation guided by LSI (LSI-guided HP) for PVI in our institute between June 2019 and July 2020 were retrospectively enrolled. Each ipsilateral PV circle was subdivided into four segments, and ablation power was set to 50 W with target LSI values at 5.0 and 4.0 for anterior and posterior walls, respectively. We compared the LSI values with and without acute conduction gaps after the initial first-pass PVI.ResultsPVI was achieved in all patients, and the incidence of first-pass PVI was 78.1% (82/105). A total of 6,842 lesion sites were analyzed, and the acute conduction gaps were observed in 23 patients (21.9%) with 45 (0.7%) lesion points. The gap formation was significantly associated with lower LSI (3.9 ± 0.4 vs. 4.6 ± 0.4, p < 0.001), lower force-time integral (82.6 ± 24.6 vs. 120.9 ± 40.4 gs, p < 0.001), lower mean contact force (5.7 ± 2.4 vs. 8.5 ± 2.8 g, p < 0.001), shorter ablation duration (10.5 ± 3.6 vs. 15.4 ± 6.4 s, p < 0.001), lower mean temperature (34.4 ± 1.4 vs. 35.6 ± 2.6°C, p < 0.001), and longer interlesion distance (4.4 ± 0.3 vs. 4.3 ± 0.4 mm, p = 0.031). As per the receiver operating characteristic analysis, the LSI had the highest predictive value for gap formation in all PVs segments, with a cutoff of 4.35 for effective ablation (sensitivity 80.0%; specificity 75.4%, areas under the curve: 0.87). The LSI of 4.55 and 3.95 had the highest predictive value for gap formation for the anterior and posterior segments of PVs, respectively.ConclusionUsing LSI-guided HP ablation for PVI, more than 4.35 of LSI for all PVs segments showed the best predictive value to avoid gap formation for achieving effective first-pass PVI. The LSI of 4.55 for the anterior wall and 3.95 for the posterior wall were the best cutoff values for predicting gap formation, respectively.

Background: When performing an electrical isolation of ipsilateral pulmonary veins (PVs) for atrial fibrillation, physicians often need additional radiofrequency (RF) ablation in the carina region between the superior and inferior PVs to achieve a right PV isolation because of intercaval bundles between the right PVs and right atrium (RA). We compared the efficacy of a high‐power and short‐duration ablation guided by unipolar signal modification (UM) with the conventional method (CM) for ablating epicardial connections between the right PV carina and RA. Methods: The study subjects consisted of patients who underwent an initial box isolation of atrial fibrillation from January 2015 to December 2019 at Nara Medical University Hospital. Among these patients, 94 and 65 patients who met the criteria were assigned to the CM and UM groups, respectively. We retrospectively analyzed the anterior ablation line of the right PV using an electroanatomical mapping system. Patients whose initial ablation line included the right PV carina were excluded. Results: Six and seven patients were, respectively, excluded from the CM and UM groups. Among 88 CM group patients, 21 needed additional right PV carina ablation, while among 58 UM group patients, 30 needed additional right PV carina ablation (p =.001). No anatomical factors were associated with the additional right PV carina ablation. Conclusions: Compared to the CM group, a box isolation was less achievable without RF ablation at the right PV carina in the UM group. We should consider a long‐duration ablation for epicardial connections between the right PV carina and RA. [ABSTRACT FROM AUTHOR]

Background: It has been demonstrated that a high‐power, short‐duration (HPSD) ablation during pulmonary vein (PV) isolation is effective and safe. However, studies about the HPSD ablation during the posterior wall isolation, the Box isolation (BOXI), are limited. We evaluated the efficacy, feasibility, and safety of HPSD ablation during BOXI. Methods: One‐hundred sixty patients with all types of atrial fibrillation underwent BOXI with HPSD ablation (n = 80) or conventional technique (n = 80). In the HPSD group, ablation was performed with 50 W and a target lesion size index of 5.0 using a contact force (CF) sensing catheter. Ablation near the esophagus was performed with 50 W for 5 seconds and a CF < 10 g. In the conventional group, ablation was performed with 30‐40 W for 30 seconds, but 20 W near the esophagus. Results: The BOXI creation (26 ± 8 minutes vs 47 ± 17 minutes, P <.0001) and procedure (65 ± 12 minutes vs 87 ± 23 minutes, P <.0001) times were significantly shorter in the HPSD group than the conventional group. The number of pacing capture sites did not differ between the two groups. No complications including gastrointestinal symptoms occurred. The atrial tachyarrhythmia‐free rate at 12‐months after a single procedure was 86.3% in the HPSD group and 76.3% in the conventional group, respectively (P =.132). The incidence of PV reconnections and gaps in the lines during the second procedure did not differ between the two groups. Conclusion: The BOXI with HPSD ablation is effective, feasible, and safe with short BOXI creation and procedure times without reducing the clinical outcomes. [ABSTRACT FROM AUTHOR]