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Pulsed field ablation (PFA) is an emerging technology for the treatment of atrial fibrillation (AF), for which pre-clinical and early-stage clinical data are suggestive of some degree of preferentiality to myocardial tissue ablation without damage to adjacent structures. Here in the MANIFEST-17K study we assessed the safety of PFA by studying the post-approval use of this treatment modality. Of the 116 centers performing post-approval PFA with a pentaspline catheter, data were received from 106 centers (91.4% participation) regarding 17,642 patients undergoing PFA (mean age 64, 34.7% female, 57.8% paroxysmal AF and 35.2% persistent AF). No esophageal complications, pulmonary vein stenosis or persistent phrenic palsy was reported (transient palsy was reported in 0.06% of patients; 11 of 17,642). Major complications, reported for ~1% of patients (173 of 17,642), were pericardial tamponade (0.36%; 63 of 17,642) and vascular events (0.30%; 53 of 17,642). Stroke was rare (0.12%; 22 of 17,642) and death was even rarer (0.03%; 5 of 17,642). Unexpected complications of PFA were coronary arterial spasm in 0.14% of patients (25 of 17,642) and hemolysis-related acute renal failure necessitating hemodialysis in 0.03% of patients (5 of 17,642). Taken together, these data indicate that PFA demonstrates a favorable safety profile by avoiding much of the collateral damage seen with conventional thermal ablation. PFA has the potential to be transformative for the management of patients with AF., (© 2024. The Author(s).)

Aims: Pulmonary vein isolation (PVI) is increasingly performed in patients with atrial fibrillation (AF). Both AF phenotype and left atrial (LA) volume have been shown to influence ablation outcome. The inter-relationship of the two is incompletely understood. We aimed to investigate the impact of AF phenotype vs. LA volume on outcome after PVI., Methods and Results: In a retrospective analysis of a prospective registry of patients undergoing a first PVI, the association of AF phenotype and LA volume index (LAVI) was assessed as well as their impact on AF recurrence during follow-up. Overall, 476 patients were enrolled (median age 63 years, 29% females, 65.8% paroxysmal AF). Obesity, hypertension, chronic kidney disease, and heart failure were all significantly more frequent in persistent AF. After 1 year, single-procedure, freedom from arrhythmia recurrence was 61.5%. Patients with paroxysmal AF had better outcomes compared with patients with persistent AF (65.6 vs. 52.7%, P = 0.003), as had patients with no/mild vs. moderate/severe LA dilation (LAVI <42 mL/m2 67.1% vs. LAVI ≥42 mL/m2 53%, P < 0.001). The combination of both parameters refined prediction of 1-year recurrence (P < 0.001). After adjustment for additional clinical risk factors in multivariable Cox proportional hazard analysis, both AF phenotype and LAVI ≥42 mL/m2 contributed significantly towards the prediction of 1-year recurrence., Conclusion: Atrial fibrillation phenotype and LA volume are independent predictors of outcome after PVI. Persistent AF with no/mild LA dilation has a similar risk of recurrence as paroxysmal AF with a moderate/severe LA dilation and should be given similar priority for ablation., Competing Interests: Conflict of interest: T.R. has received research grants from the Swiss National Science Foundation, the Swiss Heart Foundation, the Sitem Insel Support Fund, Biotronik, Boston Scientific, and Medtronic, all for work outside the submitted study. He has received speaker/consulting honoraria or travel support from Abbott/SJM, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. He has received support for his institution’s fellowship programme from Abbott/SJM, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. L.R. has received research grants from Medtronic, the Swiss National Foundation, the Swiss Heart Foundation, the Immanuel and Ilse Straub Foundation, and the Sitem Insel Support Fund, all for work outside the submitted study. He has received speaker/consulting honoraria from Abbott and Medtronic. A.H.: travel fees/educational grants from Medtronic, Biotronik, Abbott, and Philips/Spectranetics without impact on his personal remuneration. He serves as a proctor for Medtronic. He has received research grants from the Swiss National Science Foundation, the Swiss Innovation Agency Innosuisse, the Swiss Heart Foundation, the University of Bern, the University Hospital Bern, the Velux Foundation, the Hasler Foundation, the Swiss Heart Rhythm Foundation, and the Novartis Research Foundation. He is the co-founder and CEO of Act-Inno AG. All other authors have no relationships relevant to the contents of this paper to disclose., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Prediction of the chamber of origin in patients with outflow tract ventricular arrhythmias (OTVA) remains challenging. A clinical risk score based on age, sex and presence of hypertension was associated with a left ventricular outflow tract (LVOT) origin. We aimed to validate this clinical score to predict an LVOT origin in patients with OTVA., Methods: In a two-center observational cohort study, unselected patients undergoing catheter ablation (CA) for OTVA were enrolled. All procedures were performed using an electroanatomical mapping system. Successful ablation was defined as a ≥80% reduction of the initial overall PVC burden after 3 months of follow-up. Patients with unsuccessful ablation were excluded from this analysis., Results: We included 187 consecutive patients with successful CA of idiopathic OTVA. Mean age was 52 ± 15 years, 102 patients (55%) were female, and 74 (40%) suffered from hypertension. A LVOT origin was found in 64 patients (34%). A score incorporating age, sex and presence of hypertension reached 73% sensitivity and 67% specificity for a low (0-1) and high (2-3) score, to predict an LVOT origin. The combination of one ECG algorithm (V 2 S/V 3 R-index) with the clinical score resulted in a sensitivity and specificity of 81% and 70% for PVCs with R/S transition at V 3 ., Conclusion: The published clinical score yielded a lower sensitivity and specificity in our cohort. However, for PVCs with R/S transition at V 3, the combination with an existing ECG algorithm can improve the predictability of LVOT origin., (© 2023 The Authors. Pacing and Clinical Electrophysiology published by Wiley Periodicals LLC.)

Background: Bipolar voltage (BV) electrograms for left atrial (LA) substrate characterization depend on catheter design and electrode configuration., Aims: The aim of the study was to investigate the relationship between the BV amplitude (BVA) using four catheters with different electrode design and to identify their specific LA cutoffs for scar and healthy tissue., Methods and Results: Consecutive high-resolution electroanatomic mapping was performed using a multipolar-minielectrode Orion catheter (Orion-map), a duo-decapolar circular mapping catheter (Lasso-map), and an irrigated focal ablation catheter with minielectrodes (Mifi-map). Virtual remapping using the Mifi-map was performed with a 4.5 mm tip-size electrode configuration (Nav-map). BVAs were compared in voxels of 3 × 3 × 3 mm3. The equivalent BVA cutoff for every catheter was calculated for established reference cutoff values of 0.1, 0.2, 0.5, 1.0, and 1.5 mV. We analyzed 25 patients (72% men, age 68 ± 15 years). For scar tissue, a 0.5 mV cutoff using the Nav corresponds to a lower cutoff of 0.35 mV for the Orion and of 0.48 mV for the Lasso. Accordingly, a 0.2 mV cutoff corresponds to a cutoff of 0.09 mV for the Orion and of 0.14 mV for the Lasso. For healthy tissue cutoff at 1.5 mV, a larger BVA cutoff for the small electrodes of the Orion and the Lasso was determined of 1.68 and 2.21 mV, respectively., Conclusion: When measuring LA BVA, significant differences were seen between focal, multielectrode, and minielectrode catheters. Adapted cutoffs for scar and healthy tissue are required for different catheters., Competing Interests: Conflict of interest: S.K. has received funding of the ‘Stiftung für Herzschrittmacher und Elektrophysiologie’ and the ‘Freiwillige Akademische Gesellschaft Basel’. P.B. has received research funding from the ‘University of Basel’, the ‘Stiftung für Herzschrittmacher und Elektrophysiologie’, and the ‘Freiwillige Akademische Gesellschaft Basel’. F.J. is an employee of Boston Scientific. B.S. reports speaker’s bureau for Medtronic. S.O. has received research grants from the Swiss National Science Foundation and Swiss Heart Foundation, Foundation for CardioVascular Research Basel, and F. Hoffmann-La Roche Ltd., and educational and speaker grants from F. Hoffmann-La Roche Ltd., Bayer, Novartis, Sanofi AstraZeneca, Daiichi-Sankyo, and Pfizer. C.S.: Member of Medtronic Advisory Board Europe and Boston Scientitic Advisory Board Europe, received educational grants from Biosense Webster and Biotronik and a research grant from the European Union’s FP7 program and Biosense Webster and lecture and consulting fees from Abbott, Medtronic, Biosense-Webster, Boston Scientific, Microport, and Biotronik all outside the submitted work. M.K. reports personal fees from Bayer, personal fees from Böhringer Ingelheim, personal fees from Pfizer BMS, personal fees from Daiichi Sankyo, personal fees from Medtronic, personal fees from Biotronik, personal fees from Boston Scientific, personal fees from Johnson&Johnson, grants from Bayer, grants from Pfizer, grants from Boston Scientific, grants from BMS, grants from Biotronik, all outside the submitted work. Others have nothing to declare., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: Anomalous cardiac veins are not rare and pulmonary vein (PV) isolation for atrial fibrillation (AF) treatment should include these veins. Pulsed-field ablation (PFA) is a novel technology for AF ablation with excellent efficacy and safety profile. In this case series, we describe our first experience of isolation of anomalous cardiac veins using PFA in patients with AF., Methods: We report a series of patients with congenital anomalies of the cardiac veins and AF, treated with PFA. All patients underwent cardiac computed tomography for procedural planning., Results: We included five patients (four males). Anomalous cardiac veins included a connection of a left common ostium to the coronary sinus, a partial and complete drainage of the right superior PV into the superior vena cava (SVC) with and without additional atrial septal defect, a persistent left SVC and an anomalous posterior PV. All anomalous PVs were isolated using PFA. No phrenic nerve palsy or other complications occurred. PFA of an abnormal right superior PV draining into the distal SVC was possible without affecting the sinus node. After a median of 4 months, four patients were free of recurrence. One patient had recurrent AF and perimitral reentry tachycardia, probably facilitated by PFA in the mitral isthmus region during isolation of an anomalous connection of the left common ostium to the coronary sinus., Conclusions: Using systematic preprocedural imaging and three-dimensional-electroanatomic mapping, the currently available PFA system seems well suited, efficient, and versatile for the treatment of AF in patients with anomalous cardiac veins., (© 2023 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Aims: The aim of the study was to compare the 1-year efficacy and safety of a novel cryoballoon (NCB) ablation system (POLARx; Boston Scientific) for pulmonary vein isolation (PVI) compared with the standard cryoballoon (SCB) system (Arctic Front, Medtronic)., Methods and Results: Consecutive patients with atrial fibrillation (AF) undergoing PVI using the NCB and the SCB at two centres were included. We report 1-year efficacy after 12 months, short-term safety and hospitalizations within the blanking period, and predictors for AF recurrence. In case of repeat procedures, pulmonary vein (PV) reconnection patterns were characterized. Eighty patients (age 66 ± 10 years, ejection fraction 57 ± 10%, left atrial volume index 39 ± 13 mL/m2, paroxysmal AF in 64%) were studied. After a single procedure and a follow-up of 12 months, 68% in the NCB group and 70% in the SCB group showed no recurrence of AF/atrial tachycardias (P = 0.422). One patient in the NCB group suffered a periprocedural stroke with full recovery. There were no differences regarding hospitalizations during follow-up between the groups. PV reconnection observed during 12 repeat procedures (4 NCB, 8 SCB) pattern was comparable between the groups with more reconnections in the right-sided compared with the left-sided PVs., Conclusion: In this multicentre study comparing two currently available cryoballoon ablation systems for PVI, no differences were observed in the efficacy and safety during a follow-up of 12 months., Competing Interests: Conflict of interest: T.R. has received speaker/consulting honoraria or travel support from Abbott/SJM, Astra Zeneca, Brahms, Bayer, Biosense-Webster, Biotronik, Boston-Scientific, Daiichi Sankyo, Medtronic, Pfizer-BMS, and Roche, all for work outside the submitted study. He has received research grants from the Goldschmidt-Jacobson Foundation, the Swiss National Science Foundation, the Swiss Heart Foundation, the European Union (Eurostars 9799–ALVALE), the Professor Max Cloëtta Foundation, the Cardiovascular Research Foundation Basel, the University of Basel, and the University Hospital Basel. He has received support for his institution’s fellowship program from Abbott/SJM, Biosense-Webster, Biotronik, Boston-Scientific, and Medtronic for work outside the submitted study. S.H.B. has received research support from Biosense-Webster and travel grants from Biosense Webster and Boston-Scientific all for work outside the submitted study. L.R. has received speaker/consulting honoraria from Abbott/SJM and Medtronic. M.K. reports grants from the Swiss National Science Foundation, Swiss Heart Foundation, Bayer, Pfizer BMS, Boston Scientific, personal fees from Bayer, Böhringer Ingelheim, Pfizer BMS, Daiichi Sankyo, Medtronic, Biotronik, Boston Scientific, Johnson & Johnson all outside the submitted work. C.S. reports grants from the European Union’s FP7 program, Biosense-Webster and lecture and consulting fees from Abbott, Medtronic, Biosense-Webster, Boston Scientific, Microport, and Biotronik. S.K. reports grant from the Stiftung Kardiovaskuläre Forschung. The rest of the authors report no conflicts of interest. No commercial entities participated in this study., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: The aim was to report procedural and technical differences of a novel cryoballoon (NCB) ablation catheter for pulmonary vein isolation (PVI) compared to the standard cryoballoon (SCB) catheter., Methods: Consecutive patients with atrial fibrillation (AF) undergoing PVI using the NCB and the SCB were included. Procedural parameters, technical differences, acute efficacy, and safety are reported., Results: Eighty patients (age 66 ± 10 years, ejection fraction 57 ± 10%, left atrial volume index 40 ± 6 ml/m 2 ) were studied. With the NCB, 156 of 158 PVs (99%) were isolated compared to isolation of 159 of 159 PVs (100%) with the SCB. The median number of freezes in the NCB and the SCB group was 6 (IQR 5-8) and 5 (IQR 4-7), respectively (p = 0.051), with 73% and 71% of the PVs isolated with a single freeze, respectively. Nadir temperature and temperature at isolation were - 59 ± 6 °C and - 45 ± 17 °C in the NCB group and - 46 ± 7 °C and - 32 ± 23 °C in the SCB group, respectively (both p < 0.001) with no difference in time to isolation (TTI). Procedural differences were observed for the total procedure time (84 ± 29 min in the NCB group and 65 ± 17 min in the SCB group, p = 0.003). There was a peri-procedural stroke in one patient in the NCB group. Differences in catheter design were observed that may account for the differences in temperature recordings and ice cap formation., Conclusions: Acute efficacy and TTI were similar with the NCB compared to the SCB. Measured temperatures were lower with the NCB, most likely due to differences in catheter design., (© 2021. The Author(s).)

Background: Operator-directed nurse-administered (ODNA) sedation with propofol (PRO) is the preferred sedation technique for catheter ablation of atrial fibrillation (AF) in many centers., Objective: The purpose of this study was to investigate whether dexmedetomidine (DEX), an α 2 -adrenergic receptor agonist, is superior to propofol., Methods: We randomized 160 consecutive patients undergoing first AF ablation to ODNA sedation by DEX (DEX group) vs PRO (PRO group), according to a standardized protocol. Patients were unaware of treatment allocation. The primary endpoint was a composite of inefficient sedation, termination/change of sedation protocol or procedure abortion, hypercapnia (transcutaneous CO 2 >55 mm Hg), hypoxemia (SpO 2 <90%) or intubation, prolonged hypotension (systolic blood pressure <80 mm Hg), and sustained bradycardia necessitating cardiac pacing. Secondary endpoints were the components of the primary endpoint and patient satisfaction with procedural sedation, as assessed by a standardized questionnaire given the day after ablation., Results: The primary endpoint occurred in 15 DEX group and 25 PRO group patients (19% vs 31%; P = .068). Hypercapnia was significantly more frequent in PRO group patients (29% vs 10%; P = .003). There was no significant difference for the other components of the primary endpoint, and no procedure was aborted. Patient satisfaction was significantly better among PRO group patients (visual analogue scale 0-100; median 100 in PRO group vs median 93 in DEX group; P <.001)., Conclusion: Efficacy of ODNA sedation with DEX was not different from that with PRO. Hypercapnia occurs less frequently with DEX, but patient satisfaction is better with PRO sedation. In selected patients, DEX may be used as an alternative to PRO for ODNA sedation during AF ablation., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Chemical ablation by retrograde infusion of ethanol into the vein of Marshall (VOM-EI) can facilitate the achievement of mitral isthmus block. This study sought to describe the efficacy and safety of this technique., Methods and Results: Twenty-two consecutive patients (14 males, median age 71 years) with attempted VOM-EI for mitral isthmus ablation were included in the study. VOM-EI was successfully performed with a median of 4 ml of 96% ethanol in 19 patients (86%) and the mitral isthmus was successfully blocked in all (100%). Touch up endocardial and/or epicardial ablation after VOM-EI was necessary for 12 patients (63%). Perimitral flutter was present in 12 patients (63%) during VOM-EI and terminated or slowed by VOM-EI in 4 and 3 patients, respectively. The low-voltage area of the mitral isthmus region increased from 3.1 cm 2 (interquartile range [IQR] 0-7.9) before to 13.2 cm 2 (IQR: 8.2-15.0) after VOM-EI and correlated significantly with the volume of ethanol injected (p = .03). Median high-sensitive cardiac troponin-T increased significantly from 330 ng/L (IQR: 221-516) the evening of the procedure to 598 ng/L (IQR: 382-769; p = .02) the following morning. A small pericardial effusion occurred in three patients (16%), mild pericarditis in one (5%), and uneventful VOM dissection in two (11%). After a median follow-up of 3.5 months (IQR: 3.0-11.0), 10 of 18 patients (56%) with VOM-EI and available follow-up had arrhythmia recurrence. Repeat ablation was performed in five patients (50%) and peri-mitral flutter diagnosed in three (60%)., Conclusion: VOM-EI is feasible, safe, and effective to achieve acute mitral isthmus block., (© 2021 Wiley Periodicals LLC.)

Background: Radiofrequency catheter ablation of idiopathic premature ventricular complexes (PVCs) is an effective method for eliminating symptoms and preventing/reversing arrhythmia-induced cardiomyopathy. One reason for procedural failure is low PVC frequency during the procedure. We aimed to investigate the relation between pre-procedural PVC burden and outcome of idiopathic PVC catheter ablation., Methods: Patients who underwent idiopathic PVC ablation between 2013 and 2019 at two tertiary referral centers were retrospectively included. All procedures were performed using irrigated-tip ablation catheters and a 3D electro-anatomical mapping system. Sustained ablation success was defined as a ≥80% reduction of pre-procedural PVC burden determined by 24h-Holter at follow-up., Results: Overall, 254 patients (median age 54 years [IQR 42-64]; 47% male) were enrolled. The median pre-ablation PVC-burden was 22% (IQR 11-31%), which was reduced to a post-ablation PVC burden of 0.3% (IQR 0-4%) after a median of 90 days. Sustained ablation success was achieved in 182 patients (72%). Pre-procedural PVC burden did not differ between patients with sustained ablation success and recurrence during follow-up (median 21% vs. 22%, p = .76). When assessed in pre-ablation PVC-burden groups of ≤5%, 6-15%, 16-30%, and ≥31%, sustained ablation success was achieved in 67%, 75%, 71%, and 72%, respectively, with no significant difference (p = .89). Sustained ablation outcome for PVC-burden ≤5% versus >5% showed no difference either (67% vs. 72%, p = .52)., Conclusions: Pre-procedural Holter-determined PVC burden does not predict the outcome of idiopathic PVC ablation. Thus, catheter ablation may be a reasonable first choice also for patients with symptomatic yet rare PVCs., (© 2021 Wiley Periodicals LLC.)