Search

Competing Interests: Funding Support and Author Disclosures Dr Tedrow has received consulting fees from Biosense Webster and Thermedical Inc; serves on an Advisory Board for Biosense Webster; and has received honoraria for educational courses from Biosense Webster, Baylis Medical, Boston Scientific, Medtronic, and Abbot Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: Women respond more favorably to biventricular pacing (BIVP) than men. Sex differences in atrioventricular and interventricular conduction have been described in BIVP studies. Left bundle branch area pacing (LBBAP) offers advantages due to direct capture of the conduction system. We hypothesized that men could respond better to LBBAP than BIVP., Objectives: This study aims to describe the sex differences in response to LBBAP vs BIVP as the initial cardiac resynchronization therapy (CRT)., Methods: In this multicenter prospective registry, we included patients with left ventricular ejection fraction ≤35% and left bundle branch block or a left ventricular ejection fraction ≤40% with an expected right ventricular pacing exceeding 40% undergoing initial CRT with LBBAP or BIVP. The composite primary outcome was heart failure-related hospitalization and all-cause mortality. The primary safety outcome included all procedure-related complications., Results: There was no significant difference in the primary outcome when comparing men and women receiving LBBAP (P = 0.46), whereas the primary outcome was less frequent in women in the BIVP group than men treated with BIVP (P = 0.03). The primary outcome occurred less frequently in men undergoing LBBAP (29.9%) compared to those treated with BIVP (46.5%) (P = 0.004). In women, the incidence of the primary endpoint was 24.14% in the LBBAP group and 36.2% in the BIVP group; however, this difference was not statistically significant (P = 0.23). Complication rates remained consistent across all groups., Conclusions: Men and women undergoing LBBAP for CRT had similar clinical outcomes. Men undergoing LBBAP showed a lower risk of heart failure-related hospitalizations and all-cause mortality compared to men undergoing BIVP, whereas there was no difference between LBBAP and BIVP in women., Competing Interests: Funding Support and Author Disclosures Dr Diaz has received speaker honoraria and has been a proctor for Medtronic for conduction system pacing. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Funding Support and Author Disclosures Dr Sauer is a paid consultant for Biosense Webster and Boston Scientific. Dr Romero is a paid consultant for Biosense Webster, Boston Scientific, AtriCure, Abbott, and Sanofi; Dr Romero has also received research support from Biosense Webster and Boston Scientific. Dr Tedrow is a paid consultant for Biosense Webster, Abbott, Boston Scientific, and Thermedical Inc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: Catheter ablation of ventricular tachycardia (VT) typically requires radiation exposure with its potential adverse health effects. A completely fluoroless ablation approach is achievable using a combination of electroanatomical mapping and intracardiac echocardiography. Nonetheless, data in patients undergoing VT ablation are limited., Objectives: This study aimed to determine the feasibility, efficacy, and safety of VT ablation in patients with structural heart disease using a zero-fluoroscopy approach., Methods: This multicenter study included consecutive patients with ischemic and nonischemic cardiomyopathy undergoing fluoroless VT ablation. Patients requiring epicardial access or coronary angiography were excluded., Results: Between 2017 and 2023 a total of 198 patients (aged 66.4 ± 13.4 years, 76% male, 48% ischemic) were included. Most patients (95.4%) underwent left ventricular (LV) mapping and/or ablation, which was conducted via transseptal route in 54.5% (n = 103), via retrograde aortic route in 43.4% (n = 82), and using a combined approach in 2.1% (n = 4). Two-thirds of patients had a cardiac device, including a biventricular device in 15%; 2 patients had a LV assist device, and 1 patient had a mechanical aortic valve prosthesis. The mean total procedural time was 211 ± 70 minutes, and the total radiofrequency time was 30 ± 22 minutes. During a follow-up period of 22 ± 18 months, the freedom from VT recurrence was 80%, and 7.6% of patients underwent a repeated ablation. Procedural-related complications occurred in 6 patients (3.0%)., Conclusions: Fluoroless ablation of VT in structural heart disease is feasible, effective, and safe when epicardial mapping/ablation is not required., Competing Interests: Funding Support and Author Disclosures This study was supported by the Mark Marchlinski E.P. Research Fund, and the Winkleman Family Fund in Cardiac Innovation. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Electrical storm (ES) patients who fail standard therapies have a high mortality rate. Previous studies report effective management of ES with bedside, ultrasound-guided percutaneous stellate ganglion block (SGB). We report our experience with sympathetic blockade administered via a novel alternative approach: proximal intercostal block (PICB). Compared with SGB, this technique targets an area typically free of other catheters and support devices, and may pose less strict requirements for anticoagulation interruption, along with lower risk of focal neurological side effects., Objectives: The authors sought to describe the safety and efficacy of PICB in patients with refractory ES., Methods: We reviewed our institutional data on ES patients who underwent PICB between January 2018 and February 2023 to analyze procedural safety and short- and long-term outcomes., Results: A total of 15 consecutive patients with ES underwent PICB during this period. Of those, 11 patients (73.3%) were maintained on PICB alone, and 4 patients (26.6%) were maintained on combined block with SGB and PICB. Overall, 72.7% patients who were maintained on PICB alone and 77.8% patients who were maintained on bilateral PICB had excellent arrhythmia suppression. After PICB, implantable cardioverter-defibrillator therapies were significantly reduced (P < 0.05), with 93.3% of patients receiving PICB having no implantable cardioverter-defibrillator shock until discharge or heart transplant. Anticoagulation was continued in all patients and there were no procedure-related complications. Apart from mild transient neurological symptoms seen in 3 patients, no significant neurological or hemodynamic sequelae were observed., Conclusions: In patients with refractory ES, continuous PICB provided safe and effective sympathetic block (77.8% ventricular arrhythmia suppression), achievable without interruption of anticoagulation, and without significant side effects., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are considered to be acceptable as LBBAP strategies. Differences in clinical outcomes between LBBP and LVSP are yet to be determined., Objectives: The purpose of this study was to compare the outcomes of LBBP vs LVSP vs BIVP for CRT., Methods: In this prospective multicenter observational study, LBBP was compared with LVSP and BIVP in patients undergoing CRT. The primary composite outcome was freedom from heart failure (HF)-related hospitalization and all-cause mortality. Secondary outcomes included individual components of the primary outcome, postprocedural NYHA functional class, and electrocardiographic and echocardiographic parameters., Results: A total of 415 patients were included (LBBP: n = 141; LVSP: n = 31; BIVP: n = 243), with a median follow-up of 399 days (Q1-Q3: 249.5-554.8 days). Freedom from the primary composite outcomes was 76.6% in the LBBP group and 48.4% in the LVSP group (HR: 1.37; 95% CI: 1.143-1.649; P = 0.001), driven by a 31.4% absolute increase in freedom from HF-related hospitalizations (83% vs 51.6%; HR: 3.55; 95% CI: 1.856-6.791; P < 0.001) without differences in all-cause mortality. LBBP was also associated with a higher freedom from the primary composite outcome compared with BIVP (HR: 1.43; 95% CI: 1.175-1.730; P < 0.001), with no difference between LVSP and BIVP., Conclusions: In patients undergoing CRT, LBBP was associated with improved outcomes compared with LVSP and BIVP, while outcomes between BIVP and LVSP are similar., Competing Interests: Funding Support and Author Disclosures Dr Diaz has received speaker honoraria from and is a proctor for Medtronic for LBBAP. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The authors describe 3 patients presenting with cardiac sarcoidosis (CS) flare and ventricular tachycardia (VT) storm following infection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19. COVID-19-related cardiac manifestations can vary and include arrythmias, myocarditis, and exacerbation of underlying cardiovascular disease. The exact mechanism of myocardial involvement is not clear but may include abnormal host immune response and direct myocardial injury, thereby predisposing to enhanced arrhythmic risk. Arrhythmias account for 20% of COVID-19-related complications with ventricular arrythmias occurring in 5.9% of cases. Further studies are needed to better understand mechanisms underlying the intersection between COVID-19 infection and inflammatory cardiomyopathies., Competing Interests: Funding Support and Author Disclosures Dr John was supported by the Pierce Family Fellowship. Dr Winterfield has received institutional research support from Abbott Medical and Biosense Webster; and has received consulting fees from Abbott Medical, Biosense Webster, Thermedical, and Biotronik. Dr Houston has received institutional research support from Medtronic Inc and CVRx; and has received consulting fees from Edwards Lifesciences and Medtronic. Dr Tedrow has received consulting fees from Biosense Webster and Thermedical Inch; has served on an advisory board for Biosense Webster; and has received honoraria for educational courses from Biosense Webster, Boston Scientific, Medtronic, and Abbott medical. 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: Left bundle branch area pacing (LBBAP) for cardiac resynchronization therapy (CRT) is an alternative to biventricular pacing (BiVp)., Objectives: The purpose of this study was to compare the outcomes between LBBAP and BiVp as an initial implant strategy for CRT., Methods: In this prospective multicenter, observational, nonrandomized study, first-time CRT implant recipients with LBBAP or BiVp were included. The primary efficacy outcome was a composite of heart failure (HF)-related hospitalization and all-cause mortality. The primary safety outcomes were acute and long-term complications. Secondary outcomes included postprocedural New York Heart Association functional class and electrocardiographic and echocardiographic parameters., Results: A total of 371 patients (median follow-up of 340 days [IQR: 206-477 days]) were included. The primary efficacy outcome occurred in 24.2% in the LBBAP vs 42.4% in the BiVp (HR: 0.621 [95% CI: 0.415-0.93]; P = 0.021) group, driven by a reduction in HF-related hospitalizations (22.6% vs 39.5%; HR: 0.607 [95% CI: 0.397-0.927]; P = 0.021) without significant difference in all-cause mortality (5.5% vs 11.9%; P = 0.19) or differences in long-term complications (LBBAP: 9.4% vs BiVp: 15.2%; P = 0.146). LBBAP resulted in shorter procedural (95 minutes [IQR: 65-120 minutes] vs 129 minutes [IQR: 103-162 minutes]; P < 0.001) and fluoroscopy times (12 minutes [IQR: 7.4-21.1 minutes] vs 21.7 minutes [IQR: 14.3-30 minutes]; P < 0.001), shorter QRS duration (123.7 ± 18 milliseconds vs 149.3 ± 29.1 milliseconds; P < 0.001), and higher postprocedural left ventricular ejection fraction (34.1% ± 12.5% vs 31.4% ± 10.8%; P = 0.041)., Conclusions: LBBAP as an initial CRT strategy resulted in a lower risk of HF-related hospitalizations compared to BiVp. A reduction in procedural and fluoroscopy times, shorter paced QRS duration, and improvements in left ventricular ejection fraction compared with BiVp were observed., Competing Interests: Funding Support and Author Disclosures Dr Diaz has received speaker honoraria and is a proctor for Medtronic for conduction system pacing. 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: Epicardial access (EA) has emerged as an increasingly important approach for the treatment of ventricular arrhythmias and to perform other interventional cardiology procedures. EA is frequently underutilized because the current approach is challenging and carries a high risk of life-threatening complications., Objective: The purpose of this study was to determine the efficacy and safety of the SAFER (Sustained Apnea for Epicardial Access With Right Ventriculography) epicardial approach., Methods: Consecutive patients who underwent EA with the SAFER technique were included in this multicenter study. The primary efficacy outcome was the successful achievement of EA. The primary safety outcomes included right ventricular (RV) perforation, major hemorrhagic pericardial effusion (HPE), and bleeding requiring surgical intervention. Secondary outcomes included procedural characteristics and any complications. Our results were compared with those from previous studies describing other EA techniques to assess differences in outcomes., Results: A total of 105 patients undergoing EA with the SAFER approach from June 2021 to February 2023 were included. EA was used for ventricular tachycardia ablation in 98 patients (93.4%), left atrial appendage closure in 6 patients (5.7%), and phrenic nerve displacement in 1 patient (0.9%). EA was successful in all subjects (100%). The median time to EA was 7 minutes (IQR: 5-14 minutes). No cases of RV perforation, HPE, or need of surgical intervention were observed in this cohort. Comparing our results with previous studies about EA, the SAFER epicardial approach resulted in a significant reduction in major pericardial bleeding., Conclusions: The SAFER epicardial approach is a simple, efficient, effective, and low-cost technique easily reproducible across multiple centers. It is associated with lower complication rates than previously reported techniques for EA., Competing Interests: Funding Support and Author Disclosures All 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: 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.)

Objectives: This study aimed to determine the feasibility of using radioablation for arrhythmogenic a substrate modification., Background: Stereotactic body radiation therapy (SBRT) is a promising therapy for ventricular tachycardia (VT) refractory to catheter ablation., Methods: A total of 6 male patients (median age 72 years) with ischemic cardiomyopathy (left ventricular ejection fraction 20% [interquartile range (IQR): 16%-25%]) and VT refractory to antiarrhythmic medications and catheter ablations underwent SBRT to extensive scar substrate. In addition to electroanatomical mapping, 5 of 6 patients had computed tomography segmentation using MUSIC (IHU Liryc, Univ. Bordeaux and Inria Sophia Antipolis, France). Regions of wall thinning <5 mm, calcification, and intramyocardial fat were targeted for radioablation at 25 Gy., Results: The median planning target volume was 319 (IQR: 280-330) mL. Device-treated or sustained VT episodes were not significantly reduced by radioablation (median 42 [IQR: 19-269] to 29 [IQR: 0-81]; P = 0.438). However, a reduction in device shocks was observed from 12 (IQR: 3-19) to 0 (IQR: 0-1) (P = 0.046). Over a follow-up period of 231 (IQR: 212-311) days, 3 patients died of end-stage heart failure and 3 of 6 patients had possible adverse events (heart failure exacerbation, pneumonia, and an asymptomatic pericardial effusion)., Conclusions: Substrate modification using SBRT assisted by computed tomography segmentation is feasible for treatment of VT in patients with ischemic cardiomyopathy. Although a significant reduction in device shocks was observed, suboptimal VT burden reduction and significant mortality rate in this cohort of patients with advanced cardiomyopathy underscore the need to improve mechanistic understanding for antiarrhythmic effects to guide dosing and targeting of scar substrates., Competing Interests: Funding Support and Author Disclosures Dr Qian was supported by a Bushell Travelling Fellowship from the Royal Australasian College of Physicians. Dr Cochet has received speaking honoraria from Siemens Healthineers, Abbott Medical, and Biosense Webster; has received consulting fees from Farapulse; and is a shareholder in inHEART. Dr Sauer has received consulting fees from Biosense Webster. Dr Tedrow has received speaking honoraria from Abbott Medical, Biosense Webster, Medtronic, and Boston Scientific. Dr Zei has received research support and consulting fees from Varian and Biosense Webster; and has received consulting fees from 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: This study sought to identify midmyocardial arrhythmogenic substrates by examining the frequency content of unipolar endocardial surface electrograms, comparing sites with transmural scar versus sites with intramural excitable substrate (IES) as identified during needle catheter ablation for ventricular tachycardia (VT)., Background: Midmyocardial arrhythmogenic substrates are a common reason catheter ablation for VT may fail., Methods: A total of 659 intramural needle sites were studied in 26 patients (age 61 ± 9 years, 85% male, 69% nonischemic cardiomyopathy) who underwent intramural needle catheter ablation for VT. Among 136 sites where endocardial pacing did not capture (threshold >10 mA), needle pacing captured at 29 indicating IES, and did not capture at 107 indicating transmural scar. Intramural needle ablation was performed at 21 of 29 IES sites. Analysis of voltage amplitude, duration, and power spectra of endocardial and intramural needle electrograms was performed., Results: IES sites compared with transmural scar had higher endocardial unipolar electrogram voltage, 0.99 (interquartile range [IQR]: 0.69 to 1.62) mV versus 0.78 (IQR: 0.61 to 1.09) mV; p = 0.038; higher unipolar intramural needle electrogram voltage, 1.16 (0.80 to 1.69) mV versus 0.76 (0.6 to 1.12) mV; p = 0.003; higher endocardial unipolar frequency power particularly in the 5- to 20-Hz band, 1.97 (IQR: 0.93 to 3.89) mV 2 /s versus 1.03 (IQR: 0.63 to 2.22) mV 2 /s; p = 0.002; and higher unipolar intramural electrogram frequency particularly in the 0 to 10 Hz range, 3.02 (IQR: 0.98 to 6.95) mV 2 /s versus 1.33 (IQR: 0.70 to 3.13) mV 2 /s; p = 0.018. Endocardial unipolar frequency in the 5- to 20-Hz band identified sites with IES, area under the curve of 0.676; p = 0.002; power frequency integral of >0.77 mV 2 /s provided a 90% sensitivity and 41% specificity., Conclusions: The frequency content of unipolar electrograms may complement voltage in the detection of deep intramural substrates to facilitate VT catheter ablation. (Intramural Needle Ablation for Ablation of Recurrent Ventricular Tachycardia; NCT01791543)., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to investigate the value of electroanatomical voltage mapping (EAVM) to distinguish cardiac sarcoidosis (CS) from arrhythmogenic right ventricular cardiomyopathy (ARVC) in patients with ventricular tachycardia from the right ventricle (RV)., Background: CS can mimic ARVC. Because scar in ARVC is predominantly subepicardial, this study hypothesized that the relative sizes of endocardial low bipolar voltage (BV) to low unipolar voltage (UV) areas may distinguish CS from ARVC., Methods: Patients with CS affecting the RV (n = 14), patients with gene-positive ARVC (n = 13), and a reference group of patients without structural heart disease (n = 9) who underwent RV endocardial EAVM were included. RV region-specific BV and UV cutoffs were derived from control subjects. In CS and ARVC, segmental involvement was determined and low-voltage areas were measured, using <1.5 mV for BV and <3.9 mV, <4.4 mV, and <5.5 mV for UV. The ratio between low BV and low UV area was calculated generating 3 parameters: Ratio 3.9 , Ratio 4.4 and Ratio 5.5 , respectively., Results: In control subjects, BV and UV varied significantly among RV regions. The basal septum was involved in 71% of CS patients and in none of ARVC patients. Ratio 5.5 discriminated CS from ARVC the best. An algorithm including Ratio 5.5  ≥0.45 and basal septal involvement identified CS with 93% sensitivity and 85% specificity. This was validated in a separate population (CS [n = 6], ARVC [n = 10]) with 100% sensitivity and 100% specificity., Conclusions: EAVM provides detailed information about scar characteristics and scar distribution in the RV. An algorithm combining Ratio 5.5 (area BV <1.5 mV/area UV <5.5 mV) and bipolar basal septal involvement allows accurate diagnosis of (isolated) CS in patients presenting with monomorphic ventricular tachycardia from the RV., (Copyright © 2020 American College of Cardiology Foundation. All rights reserved.)

Objectives: The goal of this study was to report a multicenter series of left-sided catheter ablations performed by using intravenous direct thrombin inhibitors (DTIs) as an alternative to heparin., Background: Amidst a looming worldwide shortage of heparin, there are insufficient data to guide nonheparin-based peri-procedural anticoagulation in patients undergoing catheter ablation., Methods: This study reviewed all catheter ablations at 6 institutions between 2006 and 2019 to assess the safety and efficacy of DTIs for left-sided radiofrequency catheter ablation of atrial fibrillation and ventricular tachycardia., Results: In total, 53 patients (age 63.0 ± 9.3 years, 68% male, CHA₂DS₂-VASc [congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65 to 74 years, sex category] score 2.8 ± 1.6, left ventricular ejection fraction 46 ± 15%) underwent ablation with DTIs (75% bivalirudin, 25% argatroban) due to heparin contraindication(s) (72% heparin-induced thrombocytopenia, 21% heparin allergy, 4% protamine reaction, and 4% religious reasons). The patient's usual oral anticoagulant was continued without interruption in 69%. Procedures were performed for atrial fibrillation (64%) or ventricular tachycardia/premature ventricular contractions (36%). Transseptal puncture was undertaken in 81%, and a contact force-sensing catheter was used in 70%. Vascular ultrasound was used in 71%, and femoral arterial access was gained in 36%. A bolus followed by infusion was used in all but 4 cases, and activated clotting time was monitored peri-procedurally in 72%, with 32% receiving additional boluses. Procedure duration was 216 ± 116 min, and ablation time was 51 ± 22 min. No major bleeding or embolic complications were observed. Four patients had minor self-limiting bleeding complications, including a small pericardial effusion (<1 cm), a small groin hematoma, and hematuria., Conclusions: In this multicenter series, intravenous DTIs were safely used as an alternative to heparin for left-sided catheter ablation., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to evaluate the incidence and significance of atrioventricular (AV) block associated with ventricular arrhythmia (VA) ablation., Background: Attempted ablation of VAs that arise from the septum carries a risk of AV block., Methods: Data from 1,418 patients who had catheter ablation for drug-refractory VAs were evaluated. Two analyses were conducted. The first analysis assessed the patient and procedure characteristics associated with ablation-induced AV block. The second analysis investigated outcome differences between patients with and without AV block. For the second analysis, patients with AV block (Group I) were compared with a 1:2 propensity score-matched control group (Group II) and with patients with pre-existing AV block before ablation (Group III)., Results: Twenty-one (1.6%) patients developed AV block. In multivariable analysis, nonischemic cardiomyopathy (odds ratio: 3.33; 95% confidence interval: 1.32 to 8.40; p = 0.011) and transcoronary ethanol ablation (odds ratio: 46.50; 95% confidence interval: 14.10 to 153.00; p < 0.001) were independently associated with AV block. Subsequent to the AV block, 9 patients were upgraded from an implantable cardioverter-defibrillator to cardiac resynchronization therapy with defibrillator (CRT-D), 2 had de novo CRT-D implantation, 5 had pre-existing CRT-D, and 5 had pacing without CRT. VAs recurred in 33% of patients in Group I, 17% in Group II (log-rank p = 0.842), and 35% in Group III (p = 0.636). The composite outcome of heart failure hospitalization, heart transplantation, or death occurred in 29% of patients in Group I, 17% in Group II (p = 0.723), and 45% in Group III (p = 0.303)., Conclusions: Complete AV block occurs in fewer than 2% of patients undergoing VA ablation and does not appear to be associated with the worse outcome of heart failure hospitalization, heart transplantation, or death., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to evaluate the efficacy and safety of using half-normal saline (HNS) as the cooling radiofrequency ablation (RFA) irrigant among patients who had failed prior, standard RFA., Background: Effective control of ventricular arrhythmias that arise from mid-myocardium may be refractory to standard RFA. Recent data suggest that delivering fluid with decreased ionic concentration during open-irrigated RFA can produce deeper RFA lesions., Methods: A 12-center prospective analysis was performed of all ablations using HNS for the treatment of ventricular arrhythmias (premature ventricular complex [PVC]/ventricular tachycardia [VT]) refractory to standard ablation with normal saline irrigant., Results: HNS RFA was used clinically to target 94 PVC/VTs refractory to standard ablation. Acute success was achieved in 78 of 94 (83%), with longer-term success occurring in 78 subjects after a mean follow-up of 6.1 ± 6.7 months (range, 3.0 to 25.2 months). Steam pops were observed among 12 (12.6%) patients. There were no significant changes in electrolytes measured before and after the use of HNS, and there were no complications related to HNS use., Conclusions: The use of HNS instead of normal saline irrigant during high-power delivery targeting deep myocardial substrate is safe and effective. PVC/VT sources previously unaffected by standard ablation may be successfully ablated with improved efficiency of radiofrequency delivery using HNS., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to characterize ventricular tachycardia (VT) ablation outcomes across nonischemic cardiomyopathy (NICM) etiologies and adjust these outcomes by patient-related comorbidities that could explain differences in arrhythmia recurrence rates., Background: Outcomes of catheter ablation of VT in patients with NICM could be related to etiology of NICM., Methods: Data from 2,075 patients with structural heart disease referred for catheter ablation of VT from 12 international centers was retrospectively analyzed. Patient characteristics and outcomes were noted for the 6 most common NICM etiologies. Multivariable Cox proportional hazards modeling was used to adjust for potential confounders., Results: Of 780 NICM patients (57 ± 14 years of age, 18% women, left ventricular ejection fraction 37 ± 13%), underlying prevalence was 66% for dilated idiopathic cardiomyopathy (DICM), 13% for arrhythmogenic right ventricular cardiomyopathy (ARVC), 6% for valvular cardiomyopathy, 6% for myocarditis, 4% for hypertrophic cardiomyopathy, and 3% for sarcoidosis. One-year freedom from VT was 69%, and freedom from VT, heart transplantation, and death was 62%. On unadjusted competing risk analysis, VT ablation in ARVC demonstrated superior VT-free survival (82%) versus DICM (p ≤ 0.01). Valvular cardiomyopathy had the poorest unadjusted VT-free survival, at 47% (p < 0.01). After adjusting for comorbidities, including age, heart failure severity, ejection fraction, prior ablation, and antiarrhythmic medication use, myocarditis, ARVC, and DICM demonstrated similar outcomes, whereas hypertrophic cardiomyopathy, valvular cardiomyopathy, and sarcoidosis had the highest risk of VT recurrence., Conclusions: Catheter ablation of VT in NICM is effective. Etiology of NICM is a significant predictor of outcomes, with ARVC, myocarditis, and DICM having similar but superior outcomes to hypertrophic cardiomyopathy, valvular cardiomyopathy, and sarcoidosis, after adjusting for potential covariates., (Copyright © 2018 American College of Cardiology Foundation. All rights reserved.)

Objectives: This study sought to examine the relationship between the number of oral antiarrhythmic drug (AAD) failures before referral for ventricular tachycardia (VT) ablation and subsequent clinical outcomes., Background: Failure of AADs prompts referral for VT ablation., Methods: Consecutive patients (n = 669) with sustained VT who were referred for a first-time ablation were divided into 2 groups according to the number of oral Class 1 or 3 AAD failures before referral: single-drug failure (≤1 AAD; n = 256) or multidrug failure (>1 AADs; n = 413). Outcomes were stratified according to underlying disease type (no structural heart disease [SHD] [n = 87]; ischemic cardiomyopathy [ICM] [n = 368]; and ischemic cardiomyopathy [NICM] [n = 214]) and reported at a mean follow-up of 35 ± 46 months., Results: Patients with multidrug failure, compared with patients with single-drug failure, had more advanced SHD and required more extensive ablation to control arrhythmia. Multidrug failure, compared with single-drug failure, was associated with lower ventricular arrhythmia-free survival in ICM (46 ± 4% vs. 58 ± 6%; p = 0.03) and NICM (26 ± 5% vs. 49 ± 6%; p = 0.008), but not in the absence of SHD (71 ± 8% vs. 85 ± 7%; p = 0.10). Overall survival was lower in multidrug failure versus single-drug failure groups in patients with ICM (71 ± 3% vs. 84 ± 4%; p = 0.03) and NICM (70 ± 5% vs. 88 ± 4%; p < 0.001). Multidrug failure was independently associated with a higher risk of ventricular arrhythmia recurrence (hazard ratio: 1.6; p = 0.01) and mortality in NICM (hazard ratio: 2.6; p = 0.008), but not in ICM., Conclusions: Patients with SHD and failure of multiple oral AADs before VT ablation referral have more advanced heart disease and worse clinical outcomes following ablation, especially in NICM., (Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to evaluate the clinical outcomes of patients receiving hemodynamic support (HS) during ventricular tacchycardia (VT) ablation., Background: There are limited real-world data evaluating its effect of HS in ablation outcomes., Methods: An analysis of 1,655 patients from the International VT Ablation Center Collaborative group was performed. A total of 105 patients received HS with percutaneous ventricular assist device., Results: Patients in the HS group had lower left ventricular ejection fraction (LVEF), higher New York Heart Association (NYHA) functional class, and more implantable cardioverter-defibrillator (ICD) shocks, VT storm, and antiarrhythmic drug use (all p < 0.05). The HS group also required significantly longer fluoroscopy, procedure, and total lesion time. Acute procedural success (71.8% vs. 73.7%; p = 0.04) was significantly lower and complications (12.5% vs. 6.5%; p = 0.03) and 1-year mortality (34.7% vs. 9.3%; p < 0.001) were significantly higher in the HS group. Multivariate Cox regression analysis demonstrated HS as an independent predictor of mortality (hazard ratio: 5.01; 95% confidence interval: 3.44 to 7.20; p < 0.001). There was no significant difference in VT recurrence between groups. In a subgroup analysis including LVEF ≤20% and NYHA functional class III to IV patients, acute procedural success (74.0% vs. 70.5%; p = 0.8), complications (15.6% vs. 7.8%; p = 0.2), VT recurrence (30.2% vs. 38.1%; p = 0.44), and 1-year mortality (40.0% vs. 28.8%; p = 0.2) were no different between the HS and no-HS groups., Conclusions: Patients requiring HS were sicker with multiple comorbidities and, as expected, had a significantly higher 1-year mortality than did those patients in the no-HS group. In patients with LVEF ≤20% and NYHA functional class III to IV, there was also no significant difference in clinical outcomes when compared with no HS. Further studies are needed to systematically evaluate patients undergoing VT ablation receiving HS., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The authors sought to investigate the effect of low irrigation flow rate on lesion characteristics and ablation outcomes in a clinicopathological study., Background: Irrigated ablation produces deeper lesions compared with nonirrigated ablation, which may not be desirable in the thin-walled posterior left atrium (LA), where collateral esophageal injury is possible., Methods: Lesions were placed on the smooth posterior right atrium in 20 swine and posterior LA in 60 patients at a maximum power of 20 to 25 W with either: 1) power-controlled ablation at an irrigation flow rate of 17 ml/min (high-flow group 10 swine; n = 40) or 2) temperature-controlled ablation at an irrigation flow rate of 2 ml/min (low-flow group 10 swine; n = 20). Safety and efficacy was also compared in 326 patients undergoing AF ablation using high-flow (n = 160) or low-flow settings (n = 166) for posterior LA ablation., Results: Low-flow, compared with high-flow, lesions in swine had a higher incidence of lesions with: impedance fall ≥10 Ω, loss of pace capture, electrograms characteristic of transmural lesions, and visible lesions on anatomic inspection (p < 0.05 for all). Low-flow lesions had a maximal diameter at the endocardial surface, whereas high-flow lesions had a maximal diameter at the epicardial surface. In humans, impedance, pace capture, and transmurality data also strongly favored low-flow lesions. There was no difference in acute pulmonary vein isolation, complications, or 12-month arrhythmia-free survival between the groups., Conclusions: Low-flow irrigated ablation provides favorable lesion characteristics for posterior LA ablation without increasing the risk of adverse events., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to categorize arrhythmia mechanisms and to summarize ablation strategies in patients with persistent pulmonary vein isolation (PVI) at the time of redo procedures., Background: Persistent PVI is more frequently seen in patients undergoing redo procedures for recurrent atrial arrhythmias after catheter ablation for atrial fibrillation (AF)., Methods: Consecutive patients who underwent their first AF ablation procedures at Brigham and Women's Hospital were screened and included if they had persistent isolation of all pulmonary veins at the time of redo procedures., Results: Of 300 consecutive patients undergoing first AF ablation procedures, redo procedures were performed in 63 (21%), and 26 patients (9%) had persistent PVI. Of those, 11 had recurred with AF and 15 with organized atrial tachycardia (AT). During the index procedure, linear ablation was performed in 46% of patients with recurrent AF and 93% with recurrent organized AT (p = 0.020). At the time of last follow-up, 2 of 10 patients (20%) in the AF group and 10 of 15 patients (67%) in AT group were in sinus rhythm, without class I or III antiarrhythmic drugs (p = 0.022)., Conclusions: Patients with recurrence of atrial arrhythmia despite persistent PVI frequently present with organized AT. Linear ablation during the index procedure is associated with recurrence of organized AT. Recurrence rates after redo procedures were higher if patients had recurrent AF after the index procedure, and these patients often presented with AF again. Patients with recurrent AF despite persistent PVI may represent a population with lower success rates of catheter ablation., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to assess the incidence, operator demographics, clinical characteristics, procedural factors, and prognosis of esophageal perforation and fistula after atrial fibrillation ablation., Background: Esophageal injury is a feared complication of atrial fibrillation ablation., Methods: An Internet-based global survey soliciting anonymous information regarding esophageal perforation and fistula was emailed to 3,080 physicians. Detailed information regarding physician, patient, and procedural characteristics related to esophageal perforation with or without fistula was collected., Results: The survey was completed by 405 of 3,080 physicians (13%). Responding physicians performed 191,215 atrial fibrillation ablations and esophageal perforation with or without fistula occurred in 31 patients (0.016%) with multiple ablation catheter types despite monitoring of esophageal position or temperature during ablation in 90% of patients. Among patients who present with esophageal perforation, death, or severe neurologic injury occurred more frequently in patients with greater body mass index (30.9 ± 6.8 kg/m 2 vs. 25.8 ± 3.3 kg/m 2 ; p = 0.03), and lower left ventricular ejection fraction (55.1 ± 9.1% vs. 61.7 ± 5.4%; p = 0.04). Among analyzed patients, atrial-esophageal fistula was seen in 72%, pericardial-esophageal fistula in 14%, and esophageal perforation without fistula in 14%. Mortality was 79% with atrial-esophageal fistula and 13% in esophageal perforation without atrial-esophageal fistula., Conclusions: Esophageal perforation is rare but continues to occur with multiple catheter types despite esophageal monitoring during ablation. The prognosis of esophageal perforation is substantially improved if diagnosed and treated before development of atrial-esophageal fistula. An early surgical approach to esophageal perforation should be strongly considered regardless of evidence of fistula., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to assess loss of pulmonary vein (PV) excitability to pacing relative to the development of entrance block and the anatomic completion of the circumferential radiofrequency ablation (RFA) line., Background: During encircling RFA for PV isolation (PVI), entrance block develops before anatomic completion of encirclement (early) in some patients. We hypothesized that early entrance block may be associated with loss of PV excitability to pacing., Methods: In 30 patients undergoing PV isolation (age 61 ± 10 years, 21 men), excitability to pacing was assessed at predefined PV sites when entrance block developed and after completion of the RFA line., Results: Of 60 PV pairs, 37 developed entrance block early, with a gap ≥10 mm in the RFA line. In only 35% of PV pairs in this subgroup, both PV sleeves captured, and all of the capturing PV pairs showed exit block (no conduction from PV to atrium) despite the presence of an excitable gap. In the remaining 23 PV pairs, entrance block did not occur until encircling RFA was anatomically complete. In 83% of these PV pairs, both sleeves captured with exit block (p < 0.001 compared with early block PVs)., Conclusions: The majority of PV pairs develops entrance and exit block before complete anatomic encircling by RFA lesions. Early entrance block is frequently associated with loss of PV sleeve excitability, consistent with a spreading wave of injury or edema rather than a permanent conduction barrier. This may help to explain the significant rate of PV conduction recovery associated with the acute endpoints of entrance and exit block., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)