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Competing Interests: Funding Support and Author Disclosures Dr Nies has received a scholarship from the German Research Foundation (Deutsche Forschungsgemeinschaft). Dr Koruth has served as a consultant for, and has received grant support from Cardiofocus; has served as a consultant for Abbott, Boston Scientific, Biosense Webster, and Medtronic; has received grant support and stock options from Affera-Medtronic; has received grant support from Pulse Bioscience. Dr Reddy has served as a consultant to, and received equity from Affera-Medtronic; unrelated to this manuscript, he also serves as a consultant for and has equity in Ablacon, Acutus Medical, Apama Medical-Boston Scientific, Anumana, APN Health, Aquaheart, Atacor, Autonomix, Axon Therapies, Backbeat, BioSig, CardiaCare, CardioNXT / AFTx, Circa Scientific, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNovA EP Technology, East End Medical, EPD-Philips, EP Frontiers, Epix Therapeutics-Medtronic, EpiEP, Eximo, Farapulse-Boston Scientific, Field Medical, Focused Therapeutics, HRT, Intershunt, Javelin, Kardium, Keystone Heart, LuxMed, Medlumics, Middlepeak, Neutrace, Nuvera-Biosense Webster, Oracle Health, Restore Medical, Sirona Medical, SoundCath, Valcare; unrelated to this work, has served as a consultant for Abbott, AtriAN, Biosense-Webster, BioTel Heart, Biotronik, Boston Scientific, Cairdac, Cardiofocus, Cardionomic, CoreMap, Fire1, Gore & Associates, Impulse Dynamics, Medtronic, Novartis, Philips, Pulse Biosciences; and has equity in DRS Vascular, Manual Surgical Sciences, Newpace, Nyra Medical, Surecor, and Vizaramed. All other authors reported that they have no relationships relevant to the contents of this paper to disclose.

Background: We previously reported feasibility of irrigated needle ablation (INA) with a retractable 27-G end-hole needle catheter to treat nonendocardial ventricular arrhythmia substrate, an important cause of ablation failure., Objectives: The purpose of this study was to report outcomes and complications in our entire INA-treated population., Methods: Patients with recurrent sustained monomorphic ventricular tachycardia (VT) or high-density premature ventricular contractions (PVCs) despite radiofrequency ablation were prospectively enrolled at 4 centers. Endpoints included a 70% decrease in VT frequency or PVC burden decrease to <5,000/24 h at 6 months., Results: INA was performed in 111 patients (median: 2 failed prior ablations, 71% nonischemic heart disease, and left ventricular ejection fraction 36% ± 14%). INA acutely abolished targeted PVCs in 33 of 37 patients (89%), and PVCs were reduced to <5,000/day in 29 patients (78%). During 6-month follow-up, freedom from hospitalization was observed in 50 of 72 patients with VT (69%), and improvement or abolition of VT occurred in 47%. All patients received multiple INA applications, with more in the VT group than in the PVC group (median: 12 [IQR: 7-19] vs 7 [5-15]; P < 0.01). After INA, additional endocardial standard radiofrequency ablation was required in 23% of patients. Adverse events included 4 pericardial effusions (3.5%), 3 cases of (anticipated) atrioventricular block (2.6%), and 3 heart failure exacerbations (2.6%). During 6-month follow-up, 5 deaths occurred; none were procedure-related., Conclusions: INA achieves improved arrhythmia control in 78% of patients with PVCs and avoids hospitalization in 69% of patients with VT refractory to standard ablation at 6-month follow-up. Procedural risks are acceptable. (Intramural Needle Ablation for Ablation of Recurrent Ventricular Tachycardia, NCT01791543; Intramural Needle Ablation for the Treatment of Refractory Ventricular Arrhythmias, NCT03204981)., Competing Interests: Funding Support and Author Disclosures Dr Kurata has received a scholarship from the Japanese Heart Rhythm Society. Dr Hasegawa has received support from the International Rotary Fellowship of Healthcare Professionals. Dr Tedrow has received honoraria from Biosense Webster, Boston Scientific, and Abbott; and consulting fees from Thermedical Inc. Dr Dukkipati has received a research grant from Biosense Webster; and reports equity in Manual Surgical Sciences and Farapulse, which was acquired by Boston Scientific. Dr Richardson has received speaker honoraria from Medtronic; research funding from Medtronic and Abbott; and served as a consultant for Philips and Biosense Webster. Dr Kanagasundram has received speaker honoraria from Biosense Webster. Dr Koruth has received research grants from Affera, Farapulse, Cardiofocus, and Biosense Webster; consulting fees from Abbott, Farapulse, and Cardiofocus; and has equity in Affera. Dr John has received speaker honoraria from Abbott and Medtronic. Dr Sapp is a coholder of a patent for irrigated needle ablation with rights assigned to Brigham and Women’s Hospital; has received research grants from Biosense Webster and Abbott; and (modest) speaker or consulting honoraria from Medtronic, Abbott, Biosense Webster, and Varian. Dr Reddy has reported consulting fees and equity from Abalcon, Acutus Medical, Affera, Apama Medical, Aquaheart, Atacor, Autonomix, Backbeat, BioSig, Circa Scientific, Corvia Medical, Dinova-Hangzhou Nuomao Medtech Co, Ltd, East End Medical, EPD, Epix Therapeutics, EpiEP, Eximo, Fire1, Javelin, Kardium, Keystone Heart, LuxCath, Medlumics, Middlepeak, Nuvera, Sirona Medical, and Valcare; equity in Manual Surgical Sciences, Newpace, Surecor, Vizaramed, and Farapulse, which was acquired by Boston Scientific; and has received consulting fees from Abbott, Axon, Biosense Webster, Biotronic, Boston Scientific, Cardiofocus, Cardionomic, CardioNXT/AFTx, EBR, Impulse Dynamics, Medtronic, Philips, Pulse Biosciences, Stimda, and Thermedical. Dr Stevenson is a coholder of a patent for irrigated needle ablation with rights assigned to Brigham and Women’s Hospital; and has received speaking honoraria from Abbott, Boston Scientific, Biotronik, Biosense Webster, and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Because of its safety, "single-shot" pulsed field ablation (PFA) catheters have been developed for pulmonary vein isolation (PVI). However, most atrial fibrillation (AF) ablation procedures are performed with focal catheters to permit flexibility of lesion sets beyond PVI., Objectives: This study sought to determine the safety and efficacy of a focal ablation catheter able to toggle between radiofrequency ablation (RFA) or PFA to treat paroxysmal or persistent AF., Methods: In a first-in-human study, a focal 9-mm lattice tip catheter was used for PFA posteriorly and either irrigated RFA (RF/PF) or PFA (PF/PF) anteriorly. Protocol-driven remapping was at ∼3 months postablation. The remapping data prompted PFA waveform evolution: PULSE1 (n = 76), PULSE2 (n = 47), and the optimized PULSE3 (n = 55)., Results: The study included 178 patients (paroxysmal/persistent AF = 70/108). Linear lesions, either PFA or RFA, included 78 mitral, 121 cavotricuspid isthmus, and 130 left atrial roof lines. All lesion sets (100%) were acutely successful. Invasive remapping of 122 patients revealed improvement of PVI durability with waveform evolution: PULSE1: 51%; PULSE2: 87%; and PULSE3: 97%. After 348 ± 652 days of follow-up, the 1-year Kaplan-Meier estimates for freedom from atrial arrhythmias were 78.3% ± 5.0% and 77.9% ± 4.1% for paroxysmal and persistent AF, respectively, and 84.8% ± 4.9% for the subset of persistent AF patients receiving the PULSE3 waveform. There was 1 primary adverse event-inflammatory pericardial effusion not requiring intervention., Conclusions: AF ablation with a focal RF/PF catheter allows efficient procedures, chronic lesion durability, and good freedom from atrial arrhythmias-for both paroxysmal and persistent AF. (Safety and Performance Assessment of the Sphere-9 Catheter and the Affera Mapping and RF/PF Ablation System to Treat Atrial Fibrillation; NCT04141007 and NCT04194307)., Competing Interests: Funding Support and Author Disclosures This study was funded by a research grant from Affera Inc. Drs Reddy and Anter have received research grants from Affera, Inc. Drs Reddy, Anter, Koruth, and Jais hold stock options in Affera, Inc. Dr Reddy has served as a consultant to Kardium Inc (including Equity); is a consultant to Abbott, Ablacon, Acutus Medical, Affera-Medtronic, Apama Medical-Boston Scientific, APN Health, Aquaheart, Atacor, AtiAN, Autonomix, Axon Therapies, Backbeat, BioSig, Biosense-Webster, BioTel Heart, Biotronik, Boston Scientific, Cairdac, CardiaCare, Cardiofocus, Cardionomic, CardioNXT / AFTx, Circa Scientific, CoreMap, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNovA EP Technology, East End Medical, EBR, EPD-Philips, EP Frontiers, Epix Therapeutics, EpiEP, Eximo, Farapulse-Boston Scientific, Fire1, Focused Therapeutics, Gore & Associates, HRT, Impulse Dynamics, Intershunt, Javelin, Keystone Heart, LuxMed, Medlumics, Medtronic, Middlepeak, Neutrace, Nuvera-Biosense Webster, Oracle Health, Philips, Pulse Biosciences, Restore Medical, Sirona Medical, SoundCath, and Valcare; and has equity from Ablacon, Acutus Medical, Affera-Medtronic, Apama Medical-Boston Scientific, APN Health, Aquaheart, Atacor, Autonomix, Axon Therapies, Backbeat, BioSig, CardiaCare, CardioNXT / AFTx, Circa Scientific, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNovA EP Technology, East End Medical, EPD-Philips, EP Frontiers, Epix Therapeutics, EpiEP, Eximo, Farapulse-Boston Scientific, Focused Therapeutics, HRT, Intershunt, Javelin, Keystone Heart, LuxMed, Manual Surgical Sciences, Medlumics, Middlepeak, Neutrace, Newpace, Nuvera-Biosense Webster, Nyra Medical, Oracle Health, Restore Medical, Sirona Medical, SoundCath, Surecor, Valcare, and Vizaramed. Dr Peichl has received speaker honoraria from Abbott, Biosense Webster, Biotronik, Medtronic, MSD, Pfizer, and ProMed sro. Dr Anter has received research grants from Biosense Webster and Boston Scientific; and stock options from Itamar Medical. Dr Natale has received speaker honoraria from Boston Scientific, Biosense Webster, St. Jude Medical, Biotronik, and Medtronic; and is a consultant for Biosense Webster, Baylis Medical, Boston Scientific, Bristol-Myers Squibb, Biotronik, St. Jude Medical, and Medtronic. Dr Kautzner has received personal fees from Bayer, Biosense Webster, Boehringer Ingelheim, Medtronic, Merck Sharp & Dohme, Merit Medical, and St. Jude Medical (Abbott) for participation in scientific advisory boards; and has received speaker honoraria from Bayer, Biosense Webster, Biotronik, Boehringer Ingelheim, Boston Scientific, Daiichi Sankyo, Medtronic, Merck Sharp & Dohme, Mylan, Pfizer, ProMed sro, and St. Jude Medical (Abbott). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Preclinical studies have revealed that pulsed field ablation (PFA) lesion dimensions increase with repetitive applications at a similar electric field., Objectives: This study investigated whether pulmonary vein isolation (PVI) durability varies with single vs repetitive pulsed field (PF) applications., Methods: Atrial fibrillation patients underwent PVI using a spherical multielectrode array PFA catheter delivered with a 19-F deflectable sheath under intracardiac echocardiographic guidance. Esophagogastroduodenoscopy and brain magnetic resonance imaging were performed within 1 to 3 days, and invasive remapping at ∼2 to 3 months., Results: The patient cohort (n = 21; age 63 ± 11 years; 67% women) underwent PVI in either of 2 groups: group 1 (n = 11)-single PF application/PV; and group 2 (n = 10)-3 PF applications/PV. In both groups, PVI was acutely successful in all (100%) patients. Despite significantly longer pulse delivery times (75.2 ± 7.4 s/patient vs 24.5 ± 5.5 s/patient) the procedure times (73.2 ± 13.7 minutes vs 93.7 ± 18.5 minutes) were shorter with group 2 vs group 1. There was no stroke/transient ischemic attack, pericardial effusion, phrenic nerve injury, or esophageal complications. Esophagogastroduodenoscopy was normal in both groups of patients (n = 9). Screening brain magnetic resonance imaging revealed asymptomatic cerebral lesions (diffusion weighted imaging+/fluid attenuated inversion recovery-) in 3 of 16 (18.7%) patients. PV remapping revealed durable PVI in 62.5% PVs in group 1 (n = 10), compared with all 100% PVs in group 2 (n = 9); this translates to all PVs being durably isolated in 30% vs 100% (P < 0.05) of patients in groups 1 and 2, respectively., Conclusions: In his first-in-human trial, the "single-shot" spherical array PFA catheter was shown to safely isolate PVs. Repetitive PF application is key for lesion consolidation to maximize PVI durability., Competing Interests: Funding Support and Author Disclosures Drs Neuzil and Koruth have received grant support from Kardium Inc. Dr Reinders is an employee of and holds stock in Kardium Inc. Dr Reddy has served as a consultant to Kardium Inc (including Equity); is a consultant to Abbott, Ablacon, Acutus Medical, Affera-Medtronic, Apama Medical-Boston Scientific, APN Health, Aquaheart, Atacor, AtiAN, Autonomix, Axon Therapies, Backbeat, BioSig, Biosense-Webster, BioTel Heart, Biotronik, Boston Scientific, Cairdac, CardiaCare, Cardiofocus, Cardionomic, CardioNXT / AFTx, Circa Scientific, CoreMap, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNovA EP Technology, East End Medical, EBR, EPD-Philips, EP Frontiers, Epix Therapeutics, EpiEP, Eximo, Farapulse-Boston Scientific, Fire1, Focused Therapeutics, Gore & Associates, HRT, Impulse Dynamics, Intershunt, Javelin, Keystone Heart, LuxMed, Medlumics, Medtronic, Middlepeak, Neutrace, Nuvera-Biosense Webster, Oracle Health, Philips, Pulse Biosciences, Restore Medical, Sirona Medical, SoundCath, and Valcare; and has equity from Ablacon, Acutus Medical, Affera-Medtronic, Apama Medical-Boston Scientific, APN Health, Aquaheart, Atacor, Autonomix, Axon Therapies, Backbeat, BioSig, CardiaCare, CardioNXT / AFTx, Circa Scientific, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNovA EP Technology, East End Medical, EPD-Philips, EP Frontiers, Epix Therapeutics, EpiEP, Eximo, Farapulse-Boston Scientific, Focused Therapeutics, HRT, Intershunt, Javelin, Keystone Heart, LuxMed, Manual Surgical Sciences, Medlumics, Middlepeak, Neutrace, Newpace, Nuvera-Biosense Webster, Nyra Medical, Oracle Health, Restore Medical, Sirona Medical, SoundCath, Surecor, Valcare, and Vizaramed. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: During atrial fibrillation ablations using thermal energy, the treatment effect is attributed to not just pulmonary vein isolation (PVI), but also to modulation of the autonomic nervous system by ablation of cardiac ganglionated plexi (GP)., Objectives: This study sought to assess the impact of pulsed field ablation (PFA) on the GP in patients undergoing PVI., Methods: In the retrospective phase, heart rate was assessed pre- versus post-PVI using PFA, cryoballoon ablation, or radiofrequency ablation. In the prospective phase, a pentaspline PFA catheter was used in a protocol: 1) pre-PFA, high-frequency stimulation (HFS) identified GP sites by vagal effects; 2) PVI was performed assessing for repetitive vagal effects over each set of PF applications; 3) mapping defined PVI extent to identify those GP in the ablation zone; and 4) repeat HFS at GP sites to assess for persistence of vagal effects., Results: Between baseline and 3 months, heart rates in the retrospective radiofrequency ablation (n = 40), cryoballoon (n = 40), and PFA (n = 40) cohorts increased by 8.9 ± 11.4, 11.1 ± 9.4, and -0.1 ± 9.2 beats/min, respectively (P= 0.01 PFA vs radiofrequency ablation; P= 0.01 PFA vs cryoballoon ablation). In the prospective phase, pre-PFA HFS in 20 additional patients identified 65 GP sites. During PFA, vagal effects were noted in 45% of first PF applications, persisting through all applications in 83%. HFS post-PFA reproduced vagal effects in 29 of 38 sites (76%) in low-voltage tissue., Conclusions: PFA has minimal effect on GP. Unlike with thermal ablation, the mechanism by which PFA treats atrial fibrillation is mediated solely by durable PVI., Competing Interests: Funding Support and Author Disclosures Dr Neuzil has received grant support from, and has served as a consultant to Farapulse Inc. Dr Dukkipati has equity in Farapulse Inc. Dr Reddy has served as a consultant to and owns equity in Farapulse Inc, Ableton, Acutus Medical, Affera, Apama Medical–Boston Scientific, APN Health, Aquaheart, Atacor, Autonomix, Axon Therapies, Backbeat, BioSig, CardiaCare, CardioNXT/AFTx, Circa Scientific, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNOVA EP Technology, East End Medical, EPD-Philips, EP Frontiers, EPIX Therapeutics, EpiEP, Eximo, HRT, Intershunt, Javelin, Kardium, Keystone heart, LuxMed, Medlumics, Middlepeak, Neutrace, Nuvera-Biosense Weber, Oracle Health, Restore Medical, Sirona Medical, and Valcare, is a consultant to Abbott, AtiAN, Biosense-Webster, BioTel Heart, Biotronik, Boston Scientific, Cardiofocus, Cardionomic, CoreMap, EBR, Fire1, W. L. Gore and Associates, Impulse Dynamics, Medtronic, Philips, and Pulse Biosciences, and holds equity in Manual Surgical Sciences, Newpace, Surecor, and Vizaramed. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023. Published by Elsevier Inc.)

Objectives: This study sought to examine the effect of the return electrode's surface area on bipolar RFA lesion size., Background: Bipolar radiofrequency ablation (RFA) is typically performed between 2 3.5-mm tip catheters serving as active and return electrodes. We hypothesized that increasing the surface area of the return electrode would increase lesion dimensions by reducing the circuit impedance, thus increasing the current into a larger tissue volume enclosed between the electrodes., Methods: In step 1, ex vivo bipolar RFA was performed between 3.5-mm and custom-made return electrodes with increasing surface areas (20, 80, 180 mm 2 ). In step 2, ex vivo bipolar RFA was performed between 3.5-mm and 3.5-mm or 8-mm electrode catheters positioned perpendicular or parallel to the tissue. In step 3, in vivo bipolar RFA was performed between 3.5-mm and either 3.5-mm or 8-mm parallel electrode at the: 1) left ventricular summit; 2) interventricular septum; and 3) healed anterior infarction., Results: In step 1, increasing the surface area of the return electrode resulted in lower circuit impedance (R = -0.65; P < 0.001), higher current (R = +0.80; P < 0.001), and larger lesion volume (R = +0.88; P < 0.001). In step 2, an 8-mm return electrode parallel to tissue produced larger and deeper lesions compared with a 3.5-mm return electrode (P = 0.014 and P = 0.02). Similarly, in step 3, compared with a 3.5-mm, bipolar RFA with an 8-mm return electrode produced larger (volume: 1,525 ± 871 mm 3 vs 306 ± 310 mm 3 , respectively; P < 0.001) and more transmural lesions (88% vs 0%; P < 0.001)., Conclusions: Bipolar RFA using an 8-mm return electrode positioned parallel to the tissue produces larger lesions in comparison with a 3.5-mm return electrode., Competing Interests: Funding Support and Author Disclosures Mr Bubar is an employee of Biosense Webster. Dr Tarakji receives consultation fees from AliveCor, Medtronic, Janssen, and Pfizer. Dr Anter has received research grants and speaking honoraria from Biosense Webster, Boston Scientific, Affera Inc, and Itamar Medical; and holds stock options in Affera Inc. Dr Koruth has received research grants from Affera Inc, Farapulse, Cardiofocus, Biosense, Acutus, Kardium; has equity in Affera Inc; and serves as a consultant to Farapulse and Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The goal of this study is to determine the incidence, predictors, and outcomes of atrial fibrillation (AF) or atrial flutter (AFL) in patients hospitalized with coronavirus disease-2019 (COVID-19)., Background: COVID-19 results in increased inflammatory markers previously associated with atrial arrhythmias. However, little is known about their incidence or specificity in COVID-19 or their association with outcomes., Methods: This is a retrospective analysis of 3,970 patients admitted with polymerase chain reaction-positive COVID-19 between February 4 and April 22, 2020, with manual review performed of 1,110. The comparator arm included 1,420 patients with influenza hospitalized between January 1, 2017, and January 1, 2020., Results: Among 3,970 inpatients with COVID-19, the incidence of AF/AFL was 10% (n = 375) and in patients without a history of atrial arrhythmias it was 4% (n = 146). Patients with new-onset AF/AFL were older with increased inflammatory markers including interleukin 6 (93 vs. 68 pg/ml; p < 0.01), and more myocardial injury (troponin-I: 0.2 vs. 0.06 ng/ml; p < 0.01). AF and AFL were associated with increased mortality (46% vs. 26%; p < 0.01). Manual review captured a somewhat higher incidence of AF/AFL (13%, n = 140). Compared to inpatients with COVID-19, patients with influenza (n = 1,420) had similar rates of AF/AFL (12%, n = 163) but lower mortality. The presence of AF/AFL correlated with similarly increased mortality in both COVID-19 (relative risk: 1.77) and influenza (relative risk: 1.78)., Conclusions: AF/AFL occurs in a subset of patients hospitalized with either COVID-19 or influenza and is associated with inflammation and disease severity in both infections. The incidence and associated increase in mortality in both cohorts suggests that AF/AFL is not specific to COVID-19, but is rather a generalized response to the systemic inflammation of severe viral illnesses., Competing Interests: Funding Support and Author Disclosures Dr Koruth has received consulting fees from Abbott Laboratories, CardioFocus, Farapulse, and Vytron US, Inc. Dr Dukkipati has received grant support from Biosense Webster; and has equity with Farapulse and Manual Surgical Sciences, LLC. Dr Halperin has received consulting fees from Boehringer Ingelheim, Johnson & Johnson-Janssen Pharmaceuticals, and Medtronic. Dr Reddy is a consultant with Abbott, Ablacon, Acutus Medical, Affera, Apama Medical, Aquaheart, Atacor, Autonomix, Axon, Backbeat, BioSig, Biosense Webster, Biotronik, Boston Scientific, Cardiofocus, Cardionomic, CardioNXT/AFTx, Circa Scientific, Corvia Medical, Dinova-Hangzhou Nuomao Medtech Co., Ltd., East End Medical, EBR, EPD, Epix Therapeutics, EpiEP, Eximo, Fire1, Impulse Dynamics, Javelin, Kardium, Keystone Heart, LuxCath, Manual Surgical Sciences, Medlumics, Medtronic, Middlepeak, Newpace, Nuvera, Philips, Pulse Biosciences, Sirona Medical, Stimda, Surecor, Thermedical, and Valcare; and has equity in Ablacon, Acutus Medical, Affera, Apama, Aquaheart, Atacor, Autonomix, Backbeat, BioSig, Circa Scientific, Corvia Medical, Dinova-Hangzhou Nuomao Medtech Co., Ltd., East End Medical, EPD, Epix Therapeutics, EpiEP, Eximo, Fire 1, Javelin, Kardium, Keystone Heart, LuxCath, Manual Surgical Sciences, Medlumics, Middlepeak, Newpace, Nuvera, Sirona Medical, Surecor, Valcare, and Vizaramed. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study retrospectively assessed the safety and efficacy of permanent His bundle pacing (HBP) in patients with congenital complete heart block (CCHB)., Background: HBP has become an accepted form of pacing in adults. Its role in CCHB is not known., Methods: Seventeen patients with CCHB who underwent successful HBP were analyzed at 6 academic centers between 2016 and 2019. Nine patients had de novo implants, and 8 patients had previous right ventricular (RV) leads. Three RV paced patients had reduced left ventricular ejection fractions at the time of HBP. Implant/follow-up device parameters, New York Heart Association functional class, QRS duration, and left ventricular ejection fraction data were analyzed., Results: Patients' mean age was 27.4 ± 11.3 years, 59% were women, and mean follow-up was 385 ± 279 days. The following parameters were found to be statistically significant between implant and follow-up, respectively: impedance, 602 ± 173 Ω versus 460 ± 80 Ω (p < 0.001); and New York Heart Association functional class, 1.7 ± 0.9 versus 1.1 ± 0.3 (p = 0.014). In patients with previous RV pacing, HBP resulted in a significant decrease in QRS duration: 167.1 ± 14.3 ms versus 118.3 ± 13.9 ms (p < 0.0001). In de novo implants, HBP resulted in increases in QRS duration compared with baseline: 111.1 ± 19.4 ms versus 91.0 ± 4.8 ms (p = 0.016). Other parameters exhibited no statistically significant differences. During follow-up, 2 patients required lead revision due to elevated pacing thresholds., Conclusions: HBP seems to be safe and effective, with improvement in clinical outcomes in patients with CCHB. Larger studies with longer follow-up periods are required to confirm our findings., Competing Interests: Funding Support and Author Disclosures Dr. Dandamudi has served as advisory board member and consultant for Medtronic, Biotronik, and Abbott; and served as a steering committee member for a Medtronic clinical trial. Dr. Ellenbogen has served as a consultant for Medtronic, AtriCure, Abbott, Biosense-Webster, Biotronik, Merit Medical, and Boston Scientific. Dr. Vijayaraman has served on the advisory board for Boston Scientific and Eaglepoint LLC; served as a consultant for Abbott; and has served as a speaker and consultant for and received research funding from Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study aimed to assess the feasibility and success rates of permanent His-Purkinje conduction system pacing (HPCSP) in patients requiring pacing after transcatheter aortic valve replacement (TAVR)., Background: TAVR is associated with increased risk for atrioventricular block. HPCSP has the potential to reduce electromechanical dyssynchrony associated with right ventricular pacing. The feasibility and safety of HPCSP in this population are unknown., Methods: Consecutive patients requiring pacemakers after TAVR in whom His bundle pacing (HBP) and/or left bundle branch area pacing (LBBAP) was attempted at 5 centers were included in the study. Implant success rates, pacing characteristics, QRS duration, and left ventricular ejection fraction were assessed. Any procedure-related complications, lead revisions, heart failure hospitalizations, and deaths were documented., Results: HPCSP was successful in 55 of 65 (85%) patients studied. HBP was successful in 29 of 46 patients (63%), and LBBAP was successful in 26 of 28 (93%) patients in whom it was attempted. HBP was more successful in patients with Sapien valves than in those with CoreValves (69% vs. 44%; p < 0.05). LBBAP was associated with lower pacing thresholds and higher R-wave amplitudes at implantation compared with HBP (0.64 ± 0.3 at 0.5 ms vs. 1.4 ± 0.8 at 1 ms; p < 0.001; 14 ± 8 mV vs. 5.5 ± 5.6 mV; p < 0.001). Pacing thresholds remained stable and left ventricular ejection fraction remained unchanged during a mean follow-up of 12 ± 13.7 months., Conclusions: HPCSP is feasible in the majority of patients requiring pacemakers post-TAVR. Success rates of HBP were lower in patients with CoreValves compared to Sapien valves. LBBAP was associated with higher success rates and lower pacing thresholds compared with HBP., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The goal of this study was to determine the safety and feasibility of a novel esophageal balloon retractor (DV8) for MED during PVI., Background: The authors previously showed that mechanical esophageal deviation (MED) is feasible using an off-the-shelf metal stylet to allow uninterrupted ablation along the posterior left atrium during pulmonary vein isolation (PVI). Although it is an attractive strategy to avoid esophageal thermal injury, this technique was hampered by both the propensity for oropharyngeal trauma from the stiff stylet and the limited lateral esophageal displacement., Methods: In 200 consecutive patients undergoing atrial fibrillation ablation, the DV8 balloon retractor was used for MED; contrast was instilled into the esophagus to accurately delineate the trailing esophageal edge. Deviation was performed to maximize the distance from the trailing esophageal edge to the closest point of the ablation line (MED Effective ) and correlated to occurrences of luminal esophageal temperature elevation., Results: In patients undergoing MED during a first-ever PVI of 304 vein pairs, the MED Effective during right and left PVI were 21.2 ± 8.7 mm and 15.5 ± 6.8 mm, respectively. Deviation of at least 5 mm of MED Effective was achievable in 97.7%. Luminal esophageal temperature increases universally occurred (100%) at MED Effective  <5 mm, less often (28%) at MED Effective 5 to 20 mm, and rarely (1.9%) at MED Effective >20 mm. There were no esophageal complications, but 2 patients experienced oropharyngeal bleeding due to trauma related to device placement., Conclusions: MED with the balloon retractor safely moved the esophagus away from the site of energy delivery during atrial fibrillation ablation., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to compare a novel lesion dimension estimation approach to actual measurements of lesion dimensions on necropsy in porcine atria and ventricles., Background: An irrigated-tip, force-sensing radiofrequency catheter with 6 temperature (tip-tissue interface) sensors allows for assessment of lesion dimensions based on estimated tissue temperature. Lesion dimension assessment has not been attempted previously in atrial tissue., Methods: Ablations were performed using this catheter in all chambers. Irrigated radiofrequency was delivered using 20 to 50 W for durations that ranged from 15 to 90 s with contact force ranging from 5 to 45 g to replicate a wide spectrum of clinical conditions. All swine were then sacrificed and lesions were identified and photographed. Three independent observers made offline measurements, which were then averaged to obtain lesion width and depth for comparison with estimated dimensions based on interface tissue temperature., Results: In 9 swine, 54 atrial and 61 ventricular lesions were assessed. In the atria, the mean difference between the measured and estimated depth and width was 0.9 ± 0.74 mm and 1.2 ± 0.9 mm, respectively. Eighty percent of all lesions had a difference of ≤1.7 mm for depth and ≤1.74 mm for width. In the ventricle, the mean difference between the measured and estimated depth and width was 0.75 ± 0.6 mm and 1.66 ± 1.1 mm, respectively. Eighty percent of all lesions had a difference of ≤1.1 mm ventricular depth and ≤2.6 mm for width., Conclusions: Estimation of lesion dimensions can be achieved with clinically relevant accuracy using unique temperature signatures. These data have important implications for understanding the adequacy of lesion overlap and assessment of transmurality., (Copyright © 2017. Published by Elsevier Inc.)

Objectives: This study sought to determine the extent of lateral esophageal displacement required during mechanical esophageal deviation (MED) and to eliminate luminal esophageal temperature elevation (LET Elev ) during pulmonary vein (PV) isolation., Background: MED is a conceptually attractive strategy of minimizing esophageal injury while allowing uninterrupted energy delivery along the posterior left atrium during PV isolation., Methods: MED was performed using a malleable metal stylet within a plastic tube placed within the esophagus. Barium was instilled to characterize the trailing esophageal edge. For each MED attempt, the MED Effective , defined as the distance from the trailing esophageal edge-to-ablation line, was correlated to occurrences of LET Elev ., Results: In 114 consecutive patients/221 PV pairs undergoing MED (age 62.1 ± 11 years, 75% men, 62%/38% paroxysmal/persistent AF), esophageal stretching invariably occurred such that the esophageal edge trailed behind the plastic tube. MED Effective distances of 0 mm to 10 mm, 10 mm to 15 mm, 15 mm to 20 mm or >20 mm were achieved in 60 (27.1%), 64 (29%), 48 (21.7%), and 49 (22.2%) attempts, respectively. Overall, LET elevation >38°C occurred in 81 of 221 (36.7%) PV pairs. The incidence of LET Elev among the 4 groups was 73.3%, 35.9%, 25%, and 4.1%, respectively. MED Effective distances were 9.1 ± 6.5 mm and 18 ± 7.6 mm in patients with and without LET Elev , respectively (p < 0.0001). Three patients (2.6%) experienced clinically significant MED-related trauma, albeit only with a stiffer stylet., Conclusions: Mechanical esophageal deviation >20 mm from the PV ablation line prevents significant esophageal heating during PV isolation, but this level of displacement was difficult to safely achieve with this off-the-shelf mechanical stylet approach., (Copyright © 2017. Published by Elsevier Inc.)

Objectives: This in vivo ovine study describes the feasibility and safety of retrieving implanted leadless pacemakers (LPs)., Background: Although LPs have been shown to be removable soon after implantation, there are no data on the feasibility of removing chronically implanted LPs., Methods: This study was performed in 2 phases. In the mid-term cohort, 10 chronically (5.3 months) implanted animals underwent retrieval, followed by: 1) immediate necropsy in 5; and 2) in the remaining 5, reimplantation of a new LP followed by necropsy at 6 weeks. In the long-term cohort, 8 additional sheep underwent retrieval at 2.3 ± 0.1 years followed by necropsy. Retrieval was performed using either a single or triple loop snare. All 18 LPs (100%) were successfully retrieved. The time from retrieval catheter insertion to retrieval was 2:35 ± 01:11 and 3:04 ± 01:13 minutes in the mid-term and long-term study groups, respectively., Results: There were no significant differences in retrieval times using either snare. Intracardiac echocardiography was used pre- and post-retrieval to confirm the absence of pericardial effusion in all 8 sheep. On necropsy, there was no evidence of pericardial bleeding or perforation. Only minor tissue disruption and hemorrhage was noted at the implant site after retrieval. Histology demonstrated fibrous connective tissue at the contact sites of endocardium and LP can and at the helix. There was no evidence of pulmonary thromboembolism., Conclusions: We demonstrate the feasibility and safety of percutaneous, catheter-based retrieval in chronic LP implants of a maximum duration of approximately 2.5 years., (Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to assess the feasibility of pulmonary vein (PV) isolation using low-intensity collimated ultrasound., Background: Contemporary approaches to PV isolation are limited by the technical complexity of mapping and ablation. We describe a novel approach to left atrial anatomic rendering and PV isolation that aims to overcome some of these limitations by using low-intensity collimated ultrasound (LICU) system, which allows for near real-time geometry creation and automated ablation in a porcine model., Methods: Twenty swine were anesthetized, and the LICU ablation catheter was placed in the left atrium via percutaneous transseptal access. Ultrasound M-mode-based anatomies of the inferior PVs were successfully created, and ablation was performed under automatic robotic control along a user-defined lesion path. One animal was excluded because of device failure., Results: All target PVs in the 19 remaining animals were isolated acutely, requiring a mean of 1.6 applications. Ten animals were sacrificed acutely, and the remaining 9 survived for 35 ± 11 days. Of these 9, 1 animal was excluded from analysis because the index lasso position could not be reliably recreated. PVs in 5 of 8 animals remained isolated at sacrifice. Of the 77 total histological sections, 62 lesions (80.5%) were noted to be transmural. Lesions were homogeneous and characterized by coagulative necrosis and fibrous tissue. The mean myocardial thickness was 2.66 ± 1.80 mm, and the mean lesion depth was 4.28 ± 1.97 mm. No extra cardiac or collateral lesions were noted., Conclusions: This study demonstrates the safety and efficacy of a novel noncontact ultrasound mapping and ablation system to produce continuous transmural lesions that can isolate PVs in a porcine model., (Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)