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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.)

Background: Nearly 40% of patients with atrial fibrillation (AF) undergoing mitral valve surgery do not receive concomitant ablation despite societal guidelines. We assessed barriers to implementation of this evidence-based practice through a survey of cardiac surgeons in 2 statewide quality collaboratives., Methods: Adult cardiac surgeons across 2 statewide collaboratives were surveyed on their knowledge and practice regarding AF ablation. Questions concerning experience, clinical practice, case scenarios, and barriers to implementation were included., Results: Among 66 respondents (66 of 135; 48.9%), the majority reported "very comfortable/frequently use" cryoablation (53 of 66; 80.3%) and radiofrequency (55 of 66; 83.3%). Only 12.1% (8/66) were not aware of the recommendations. Approximately one-half of the respondents reported learning AF ablation in fellowship (50.0%; 33 of 66) or attending courses (47.0%; 31 of 66). Responses to clinical scenarios demonstrated wide variability in practice patterns. One-half of the respondents reported no barriers; others cited increased cross-clamp time, excessive patient risk, and arrhythmia incidence as obstacles. Desired interventions included cardiology/electrophysiology support, protocols, pacemaker rate information, and education in the form of site visits, videos and proctors., Conclusions: Knowledge of evidence-based recommendations and practice patterns vary widely. These data identify several barriers to implementation of concomitant AF ablation and suggest specific interventions (mentorship/support, protocols, research, and education) to overcome these barriers., (Copyright © 2021 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Aims: We studied the extent/area of electrical pulmonary vein isolation (PVI) after either pulsed field ablation (PFA) using a pentaspline catheter or thermal ablation technologies., Methods and Results: In a clinical trial (NCT03714178), paroxysmal atrial fibrillation (PAF) patients underwent PVI with a multi-electrode pentaspline PFA catheter using a biphasic waveform, and after 75 days, detailed voltage maps were created during protocol-specified remapping studies. Comparative voltage mapping data were retrospectively collected from consecutive PAF patients who (i) underwent PVI using thermal energy, (ii) underwent reablation for recurrence, and (iii) had durably isolated PVs. The left and right PV antral isolation areas and non-ablated posterior wall were quantified. There were 20 patients with durable PVI in the PFA cohort, and 39 in the thermal ablation cohort [29 radiofrequency ablation (RFA), 6 cryoballoon, and 4 visually guided laser balloon]. Pulsed field ablation patients were younger with shorter follow-up. Left atrial diameter and ventricular systolic function were preserved in both cohorts. There was no significant difference between the PFA and thermal ablation cohorts in either the left- and right-sided PV isolation areas, or the non-ablated posterior wall area. The right superior PV isolation area was smaller with PFA than RFA, but this disappeared after propensity score matching. Notch-like normal voltage areas were seen at the posterior aspect of the carina in the balloon sub-cohort, but not the PFA or RFA cohorts., Conclusion: Catheter-based PVI with the pentaspline PFA catheter creates chronic PV antral isolation areas as encompassing as thermal energy ablation., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Importance: Early rhythm control of atrial fibrillation (AF) with either antiarrhythmic drugs (AADs) or catheter ablation has been reported to improve cardiovascular outcomes compared with usual care; however, the optimal therapeutic modality to achieve early rhythm control is unclear., Objective: To assess the safety and efficacy of AF ablation as first-line therapy when compared with AADs in patients with paroxysmal AF., Data Sources: PubMed/MEDLINE, Scopus, Google Scholar, and various major scientific conference sessions from January 1, 2000, through November 23, 2020., Study Selection: Randomized clinical trials (RCTs) published in English that had at least 12 months of follow-up and compared clinical outcomes of ablation vs AADs as first-line therapy in adults with AF. The quality of individual studies was assessed using the Cochrane risk of bias tool. Six RCTs met inclusion criteria, including 1212 patients., Data Extraction and Synthesis: Two investigators independently extracted data. Reporting was performed in compliance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) guidelines. Analysis was performed using a random-effects model with the Mantel-Haenszel method, and results are presented as 95% CIs., Main Outcomes and Measures: Main outcomes were safety and efficacy of AF ablation as first-line therapy when compared with AADs. Trials were evaluated as having low risk of selection and attrition biases, high risk of performance bias, and with unclear risk for detection biases due to unblinding and open-label designs., Results: A total of 6 RCTs involving 1212 patients with AF were included (609 were randomized to AF ablation and 603 to drug therapy; mean [SD] age, 56 [11] years). Compared with AADs, catheter ablation use was associated with reductions in recurrent atrial arrhythmia (32.3% vs 53%; risk ratio [RR], 0.62; 95% CI, 0.51-0.74; P < .001; I2 = 40%), with a number needed to treat with ablation to prevent 1 arrhythmia of 5. Use of ablation was also associated with reduced symptomatic atrial arrhythmia (11.8% vs 26.4%; RR, 0.44; 95% CI, 0.27-0.72; P = .001; I2 = 54%) and hospitalization (5.6% vs 18.7%; RR, 0.32; 95% CI, 0.19-0.53; P < .001) with no significant difference in serious adverse events between the groups (4.2% vs 2.8%; RR, 1.52; 95% CI, 0.81-2.85; P = .19)., Conclusions and Relevance: In this meta-analysis of randomized clinical trials including first-line therapy of patients with paroxysmal AF, catheter ablation compared with antiarrhythmic drugs was associated with reductions in recurrence of atrial arrhythmias and hospitalizations, with no difference in major adverse events.

Background: Same-day discharge (SDD) after atrial fibrillation (AF) ablation is increasingly being considered. This study examined the barriers and financial impact associated with SDD in a contemporary cohort of patients undergoing elective AF ablation., Methods: A single center retrospective review was conducted of the 249 first case-of-the-day outpatient AF ablations performed in 2019 to evaluate the proportion of patients that could have undergone SDD. Barriers to SDD were defined as any intervention that prevented SDD by 8 p.m. The financial impact of SDD was based on savings from avoidance of the overnight hospital stay and revenue related to management of chest pain facilitated by a vacant hospital bed., Results: SDD could have occurred in 157 patients (63%) without change in management and in up to 200 patients (80%) if avoidable barriers were addressed. Barriers to SDD included non-clinical logistical issues (43%), prolonged post-procedure recovery (42%) and minor procedural complications (15%). On multivariate analysis, factors associated with barriers to SDD included increasing age (P = .01), left ventricular ejection fraction ≤ 35% (P = .04), and severely dilated left atrium (P = .04). The financial gain from SDD would have ranged from $1,110,096 (assuming discharge of 63% of eligible patients) to $1,480,128 (assuming 80% discharge) over the course of a year., Conclusions: Up to 80% of patients undergoing outpatient AF ablation were amenable to SDD if avoidable delays in care had been anticipated. Based on reduced hospital operating expenses and increased revenue from management of individuals with chest pain, this would translate to a financial savings of ∼$1.5 million., (© 2021 Wiley Periodicals LLC.)

Objectives: This study sought to determine the impact of adjunctive renal sympathetic denervation to catheter ablation in patients with atrial fibrillation (AF) and history of hypertension., Background: There are limited data regarding the impact of upstream adjunctive renal sympathetic denervation (RSDN) to pulmonary vein isolation (PVI) in patients with symptomatic atrial fibrillation (AF) and hypertension., Methods: The data for this study were obtained from 2 prospective randomized pilot studies, the HFIB (Adjunctive Renal Denervation to Modify Hypertension and Sympathetic tone as Upstream Therapy in the Treatment of Atrial Fibrillation)-1 (n = 30) and HFIB (Adjunctive Renal Denervation to Modify Hypertension and Sympathetic tone as Upstream Therapy in the Treatment of Atrial Fibrillation)-2 (n = 50) studies, and we performed a meta-analysis including all published studies comparing RSDN+PVI versus PVI alone up to January 25, 2020, in patients with AF and hypertension., Results: At 24 months, AF recurrence occurred in 53% and 38% in the PVI and PVI+RSDN groups (p = 0.43) in the HFIB-1 study, respectively, and 27% and 25% in the PVI and PVI+RSDN groups (p = 0.80) in the HFIB-2 study, respectively. When combined in a meta-analysis including 6 studies (n = 725), adjunctive RSDN significantly decreased the risk of AF recurrence (risk ratio [RR]: 0.68; 95% confidence interval [CI]: 0.55 to 0.83; p = 0.0002; I 2  = 0%) when compared with PVI. Six renal artery complications occurred in the HFIB-1 study and none occurred in the HFIB-2 study with RSDN. However, in the meta-analysis, there were no significant differences in overall complications between both groups (RR: 1.43; 95% CI: 0.63 to 3.22; p = 0.40; I 2  = 7%). When compared with baseline, RDSN significantly reduced the systolic blood pressure (-12.1 mm Hg; 95% CI: -20.9 to -3.3 mm Hg; p < 0.007; I 2  = 99%) and diastolic blood pressure (-5.60 mm Hg; 95% CI: -10.05 to -1.10 mm Hg; p = 0.01; I 2  = 98%) on follow-up., Conclusions: The pilot HFIB-1 and HFIB-2 studies did not demonstrate a benefit with RSDN as an adjunctive upstream therapy during PVI. However, in the meta-analysis, adjunctive RSDN to PVI appears to be safe, and improves clinical outcomes in AF patients with a history of hypertension., Competing Interests: Author Disclosures The HFIB-1 study was sponsored by Biosense Webster. The HFIB-2 study was sponsored by Boston Scientific. Dr. Cuoco has served as a consultant for St. Jude Medical and Boston Scientific. Dr. Mansour has received research grant support from Abbott, Biosense Webster, Johnson and Johnson, Boston Scientific, Medtronic, Pfizer, Boehringer Ingelheim, and Sentre Heart; has served as a consultant for Abbott, Biosense Webster, Jonhson and Johnson, Boston Scientific, Janssen, Medtronic, Philips, Novartis, and Sentre Heart; and owns equity interest in Affera, EPS Solutions, and NewPace Ltd. Dr. Lakkireddy has served as a steering committee member for the Amulet and Amaze IDE studies; and received consulting fees from Abbott. Dr. Michaud has served as a consultant for Biosense Webster, Boston Scientific, and Abbott; and has received honoraria from Biosense Webster, Boston Scientific, Biotronik, Medtronic, and Abbott. Dr. Dukkipati owns equity interest in Manual Surgical Sciences and Farapulse; and has received research grant support from Biosense Webster. Dr. Reddy has served as an unpaid consultant to and received grant support from Biosense Webster and Boston Scientific. Additional disclosures unrelated to this manuscript are listed in the Supplemental Appendix. 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.)

Background: Pulmonary vein (PV) stenosis is an important potential complication of PV isolation using thermal modalities such as radiofrequency ablation (RFA). Pulsed field ablation (PFA) is an alternative energy that causes nonthermal myocardial cell death., Objective: The purpose of this study was to compare the effect of PFA vs RFA on the incidence and severity of PV narrowing or stenosis., Methods: Data were analyzed from 4 paroxysmal atrial fibrillation ablation trials using either PFA or RFA; because of absent CT scans or poor computed tomography scan quality, 73 of 153 patients (47.7%) were excluded. Baseline and 3-month cardiac computed tomography scans were reconstructed into 3-dimensional images, and the long and short axes of the PV ostia were quantitatively and qualitatively assessed in a randomized blinded manner by 2 physicians., Results: A total of 299 PVs from 80 patients after either PFA (n = 37) or RFA (n = 43) were enrolled. PV ostial diameters decreased significantly less with PFA than with RFA (% change; long axis: 0.9% ± 8.5% vs -11.9% ± 16.3%; P < .001 and short axis: 3.4% ± 12.7% vs -12.9% ± 18.5%; P < .001). After a combined quantitative/qualitative analysis, mild (30%-49%), moderate (50%-69%), or severe (70%-100%) PV narrowing was observed, respectively, in 9.0% (15 of 166), 1.8% (3 of 166), and 1.2% (2 of 166) of PVs in the RFA cohort but in none of the PVs after PFA (P < .001). Overall, PV narrowing/stenosis was present in 0% and 0% vs 12.0% and 32.5% of PVs and patients who underwent PFA and RFA, respectively., Conclusion: This study indicates that unlike after RFA, the incidence and severity of PV narrowing/stenosis after PV isolation is virtually eliminated with PFA., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Aims: During atrial fibrillation ablation, oesophageal heating typically prompts reduction or termination of radiofrequency energy delivery. We previously demonstrated oesophageal temperature rises are associated with posterior left atrial pulmonary vein reconnection (PVR) during redo procedures. In this study, we assessed whether mechanical oesophageal deviation (MED) during an index procedure minimizes posterior wall PVRs during redo procedures., Methods and Results: Patients in whom we performed a first-ever procedure followed by a clinically driven redo procedure were divided based on both the use of MED for oesophageal protection and the ablation catheter employed (force or non-force sensing) in the first procedure. The PVR sites were compared between MED using a force-sensing catheter (MEDForce), or no MED with a non-force (ControlNoForce) or force (ControlForce) sensing catheter. Despite similar clinical characteristics, the MEDForce redo procedure rate (9.2%, 26/282 patients) was significantly less than the ControlNoForce (17.2%, 126/734 patients; P = 0.002) and ControlForce (17.5%, 20/114 patients; P = 0.024) groups. During the redo procedure, the posterior PVR rate with MEDForce (2%, 1/50 PV pairs) was significantly less than with either ControlNoForce (17.7%, 44/249 PV pairs; P = 0.004) or ControlForce (22.5%, 9/40 PV pairs; P = 0.003), or aggregate Controls (18.3%, 53/289 PV pairs; P = 0.006). However, the anterior PVR rate with MEDForce (8%, 4/50 PV pairs) was not significantly different than Controls (aggregate Controls-3.5%, 10/289 PV pairs, P = 0.136; ControlNoForce-2.4%, 6/249 PV pairs, P = 0.067; ControlForce-10%, 4/40 PV pairs, P = 1.0)., Conclusion: Oesophageal deviation improves the durability of the posterior wall ablation lesion set during AF ablation., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

This article has been corrected. The original version (PDF) is appended to this article as a Supplement., Background: Atrial fibrillation (AF) and heart failure (HF) frequently coexist and are associated with increased morbidity and mortality risk., Purpose: To compare benefits and harms between catheter ablation and drug therapy in adult patients with AF and HF., Data Sources: ClinicalTrials.gov, PubMed, Web of Science (Clarivate Analytics), EBSCO Information Services, Cochrane Central Register of Controlled Trials, Google Scholar, and various scientific conference sessions from 1 January 2005 to 1 October 2018., Study Selection: Randomized controlled trials (RCTs) published in English that had at least 6 months of follow-up and compared clinical outcomes of catheter ablation versus drug therapy in adults with AF and HF., Data Extraction: 2 investigators independently extracted data and assessed study quality., Data Synthesis: 6 RCTs involving 775 patients met inclusion criteria. Compared with drug therapy, AF ablation reduced all-cause mortality (9.0% vs. 17.6%; risk ratio [RR], 0.52 [95% CI, 0.33 to 0.81]) and HF hospitalizations (16.4% vs. 27.6%; RR, 0.60 [CI, 0.39 to 0.93]). Ablation improved left ventricular ejection fraction (LVEF) (mean difference, 6.95% [CI, 3.0% to 10.9%]), 6-minute walk test distance (mean difference, 20.93 m [CI, 5.91 to 35.95 m]), peak oxygen consumption (Vo2max) (mean difference, 3.17 mL/kg per minute [CI, 1.26 to 5.07 mL/kg per minute]), and quality of life (mean difference in Minnesota Living with Heart Failure Questionnaire score, -9.02 points [CI, -19.75 to 1.71 points]). Serious adverse events were more common in the ablation groups, although differences between the ablation and drug therapy groups were not statistically significant (7.2% vs. 3.8%; RR, 1.68 [CI, 0.58 to 4.85])., Limitation: Results driven primarily by 1 clinical trial, possible patient selection bias in the ablation group, lack of patient-level data, open-label trial designs, and heterogeneous follow-up length among trials., Conclusion: Catheter ablation was superior to conventional drug therapy in improving all-cause mortality, HF hospitalizations, LVEF, 6-minute walk test distance, Vo2max, and quality of life, with no statistically significant increase in serious adverse events., Primary Funding Source: None.

In contrast to ventricular tachycardia (VT) that occurs in the setting of a structurally normal heart, VT that occurs in patients with structural heart disease carries an elevated risk for sudden cardiac death (SCD), and implantable cardioverter-defibrillators (ICDs) are the mainstay of therapy. In these individuals, catheter ablation may be used as adjunctive therapy to treat or prevent repetitive ICD therapies when antiarrhythmic drugs are ineffective or not desired. However, certain patients with frequent premature ventricular contractions (PVCs) or VT and tachycardiomyopathy should be considered for ablation before ICD implantation because left ventricular function may improve, consequently decreasing the risk of SCD and obviating the need for an ICD. The goal of this paper is to review the pathophysiology, mechanism, and management of VT in the setting of structural heart disease and discuss the evolving role of catheter ablation in decreasing ventricular arrhythmia recurrence., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Catheter ablation of ventricular tachycardia (VT) is being increasingly performed; yet, there is often confusion regarding indications, outcomes, and how to identify those patient populations most likely to benefit. The management strategy differs between those with structural heart disease and those without. For the former, an implantable cardioverter-defibrillator (ICD) is typically required due to an elevated risk for sudden cardiac death, and catheter ablation can be used as adjunctive therapy to treat or prevent repetitive ICD therapies. In contrast, VT or premature ventricular contractions in the setting of a structurally normal heart carries a low risk for sudden cardiac death; accordingly, there is typically no indication for an ICD. In these patients, catheter ablation is considered for symptom management or to treat tachycardiomyopathy and is potentially curative. Here, the authors discuss the pathophysiology, mechanism, and management of VT that occurs in the setting of a structurally normal heart and the role of catheter ablation., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Introduction: There is a paucity of data in favor of mechanical support during catheter ablation of ventricular tachycardia (VT). This study investigated the outcomes of VT ablation associated with mechanical support using percutaneous ventricular assist device (PVAD) versus intra-aortic balloon pump (IABP)., Methods and Results: We retrospectively examined the outcomes of patients who underwent VT ablation associated with PVAD versus IABP from 2010 to 2013, captured by the Medicare Inpatient Standard Analytic File database. Data from 345 patients (PVAD = 230, IABP = 115) were examined. On admission, the incidence of heart failure was higher in PVAD (84.3% vs. 73.0%; P = 0.01) with similar rates of renal failure in PVAD versus IABP (33.0% vs. 37.4%; P = 0.42). However, PVAD was associated with reduced in-hospital cardiogenic shock (9.1% vs. 23.5%; P  <  0.001), renal failure (11.7% vs. 21.7%; P = 0.01), and length of stay (8.4 ± 7.9 vs. 10.6 ± 7.5; P < 0.001), but with greater hospital discharges to home/self-care (66.0% vs. 51.6%; P = 0.02). Index mortality (6.5% vs. 19.1%; P = 0.001) and mortality in patients with cardiogenic shock (18.2% vs. 41.2%; P = 0.03) were significantly lower with PVAD versus IABP. Furthermore, PVAD was associated with lower all-cause (27.0% vs. 38.7%; P = 0.04) and heart failure-related (21.4% vs. 33.3%; P = 0.03) 30-day hospital readmissions, but with similar redo-VT ablation rates at 1 year (10.2% vs. 14.0%; P = 0.34)., Conclusion: Among the cases captured by the Medicare database, catheter ablation of VT associated with mechanical support using PVAD was associated with reduced in-hospital cardiogenic shock, renal failure, length of stay, hospital readmissions and mortality, but no difference in redo-VT ablation at 1 year., (© 2017 Wiley Periodicals, Inc.)

Aim: During ablation of the posterior wall (PW), luminal oesophageal temperature elevation (OTE) prompts attenuation of radiofrequency (RF) energy delivery to minimize oesophageal injury. This strategy on lesion efficacy is unknown. The goal of this study was to analyse the relationship between OTE and pulmonary vein reconnection (PVR)., Methods and Results: During the index antral pulmonary vein (PV) isolation procedure with an irrigated RF ablation catheter, OTE was detected with a multisensor oesophageal temperature probe. Posterior wall ablation did not exceed 25 W and was terminated when the temperature was ≥38.5°C. Patients undergoing redo procedures (n = 142) were studied for PW sites of PVR along 4 segments: left and right superior, and left and right inferior. Pulmonary vein reconnections had occurred in 51 of the 142 patients (36%), in 58 of 284 PV pairs (20%). Among these 58 reconnected pairs, 83% (n = 48) were along the PW. Oesophageal temperature elevation had occurred in 30 patients (59%). No difference in characteristics was seen between the patients with OTE (n = 30) and those without (n = 21). For superior segments, there was no interaction between the presence or absence of OTE and PVR. For inferior segments, there were more PVRs in the group with OTE: for the right-inferior segment, the PVR rate was 72% for OTE cases vs. 42% without (P = 0.04), and for the left-inferior segment, the PVR rate was 44% for OTE cases vs. 22.9% without (P = 0.12)., Conclusion: Pulmonary vein reconnections are predominantly posteriorly located. Along the right- and left-inferior PW segments, there was an association with elevated oesophageal temperature during the index procedure., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.)

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.)

Background: Although percutaneous left ventricular assist devices (pLVADs) facilitate mapping and ablation of hemodynamically unstable ventricular tachycardia (VT), there is limited data whether clinical outcomes are improved. We sought to retrospectively compare the outcomes of patients undergoing scar-related VT ablation with and without pLVAD support., Methods and Results: The study population comprised 194 patients (109 pLVAD and 85 non-pLVAD). The pLVAD group more often had dilated cardiomyopathy (33% versus 13%; P =0.001), New York Heart Association heart failure class ≥III (51% versus 25%; P <0.001), lower left ventricular ejection fractions (26±10% versus 39±16%; P <0.001), and electrical storm (49% versus 34%; P =0.04). Procedure times (422±112 versus 330±92 minutes; P <0.001), postablation VT inducibility (20% versus 7%; P =0.02), and length of subsequent hospitalization (median 6 versus 4 days; P =0.001) were all higher in the pLVAD group. During median follow-up of 215 days, the primary end point (recurrent VT, heart transplantation, or death) occurred in 36% of the pLVAD versus 26% of the non-pLVAD groups ( P =0.14). After propensity matching for differences between groups, no differences were seen between groups for both acute procedural outcomes and the primary end point., Conclusions: In this large single-center scar-related VT ablation experience, despite the worse clinical status of the patients selected for pLVAD support, clinical outcomes were better than expected and were similar to healthier patients not receiving hemodynamic support. Patients with dilated cardiomyopathy presenting with electrical storm, advanced heart failure, and severe left ventricular dysfunction most frequently received hemodynamic support during VT ablation., (© 2017 American Heart Association, Inc.)

This review discusses the role of hemodynamic support for catheter ablation of unstable ventricular tachycardia, using commercially available mechanical circulatory support devices (intra-aortic balloon pump, Impella, TandemHeart, extracorporeal membrane oxygenation) and analyzes the published clinical experience of the safety and efficacy of these devices during ventricular tachycardia ablation. Appropriate selection of patients, device-specific characteristics, and hemodynamic monitoring is also discussed., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Among patients undergoing mitral-valve surgery, 30 to 50% present with atrial fibrillation, which is associated with reduced survival and increased risk of stroke. Surgical ablation of atrial fibrillation has been widely adopted, but evidence regarding its safety and effectiveness is limited., Methods: We randomly assigned 260 patients with persistent or long-standing persistent atrial fibrillation who required mitral-valve surgery to undergo either surgical ablation (ablation group) or no ablation (control group) during the mitral-valve operation. Patients in the ablation group underwent further randomization to pulmonary-vein isolation or a biatrial maze procedure. All patients underwent closure of the left atrial appendage. The primary end point was freedom from atrial fibrillation at both 6 months and 12 months (as assessed by means of 3-day Holter monitoring)., Results: More patients in the ablation group than in the control group were free from atrial fibrillation at both 6 and 12 months (63.2% vs. 29.4%, P<0.001). There was no significant difference in the rate of freedom from atrial fibrillation between patients who underwent pulmonary-vein isolation and those who underwent the biatrial maze procedure (61.0% and 66.0%, respectively; P=0.60). One-year mortality was 6.8% in the ablation group and 8.7% in the control group (hazard ratio with ablation, 0.76; 95% confidence interval, 0.32 to 1.84; P=0.55). Ablation was associated with more implantations of a permanent pacemaker than was no ablation (21.5 vs. 8.1 per 100 patient-years, P=0.01). There were no significant between-group differences in major cardiac or cerebrovascular adverse events, overall serious adverse events, or hospital readmissions., Conclusions: The addition of atrial fibrillation ablation to mitral-valve surgery significantly increased the rate of freedom from atrial fibrillation at 1 year among patients with persistent or long-standing persistent atrial fibrillation, but the risk of implantation of a permanent pacemaker was also increased. (Funded by the National Institutes of Health and the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00903370.).

Introduction: Standard unipolar radiofrequency ablation (RFA) is typically successful in eliminating premature ventricular contractions (PVCs) originating from the ventricular outflow tract region. In a minority of cases, this approach may be ineffective. We report 4 cases where bipolar RFA was attempted after failed unipolar RFA., Methods: From a total of 73 consecutive PVC ablations, 4 patients underwent bipolar RFA after failed unipolar ablation. Three-dimensional electroanatomic activation mapping of the right and left ventricular outflow (RVOT and LVOT), coronary sinus, and aortic root was performed., Results: Mean age was 53 ± 22 years, 3 male. The mean 24-hour PVC burden in these patients was 33,107 ± 8,712. In 3 of 4 patients, the RVOT activation was earlier than the left side. The earliest activation on the left was in the right coronary cusp in 2 patients and left coronary cusp in 2. Unipolar RFA delivered sequentially at the site of earliest RVOT and then earliest aortic cusp sites failed to eradicate the PVCs in all 4 patients. Subsequently, bipolar RFA was applied between irrigated catheters placed at the earliest RVOT and aortic root sites. This approach eliminated PVCs in 3 of 4 (75%) cases. At a median follow-up of 4 months, those with successful bipolar RFA had no recurrence of clinical PVCs., Conclusions: This report demonstrates the potential utility of bipolar RFA in patients with outflow tract PVCs that fail unipolar RFA., (© 2014 Wiley Periodicals, Inc.)

Background: The disparity between catheter and tissue temperatures during irrigated RF ablation frustrates one's ability to predict steam pops. Microwave radiometry allows for "volumetric" temperature assessment-i.e., within a circumscribed volume around the catheter tip-permitting, direct assessment of temperature during ablation. The aim of this study was to examine (i) the ability of microwave radiometry to predict steam pops, and (ii) compare this to traditional parameters such as power, catheter temperature, and impedance., Methods and Results: Irrigated RF ablation was performed in 8 sheep using the Tempasure ablation catheter in all chambers. Power, impedance, catheter tip, and volumetric temperature were continually monitored. Ablation was terminated after a pop or at 60 seconds. A pop was defined as an audible or visualized pop (intracardiac echocardiography). Predictors of pops were determined by univariate and multivariate GEE logistic regression modeling. A total of 48 pops occurred during 143 lesions applied at 20-50 W. There was no association between the chamber of the heart and the occurrence of pops. The rate of rise of volumetric temperature (greater than 1.5 °C/s) was the single best predictor of pops (OR: 88.8 [95% CI: 12-604], P < 0.0007). Pops only occurred above a maximum volumetric temperature threshold of 89 °C., Conclusions: During irrigated RF ablation, steam pop occurrence can be predicted by both, the rate of rise and the maximum volumetric temperature measured by microwave radiometry., (© 2013 Wiley Periodicals, Inc.)

Background: The initial experience with left atrial esophageal fistula (LAEF) secondary to atrial fibrillation (AF) ablation procedures revealed a near-universal mortality. A comprehensive description of the principles of LAEF repair in the modern era and its resulting impact on morbidity and mortality are lacking in the literature., Objective: To describe the presentation, surgical management, and outcomes of patients with LAEF., Methods: A retrospective cohort analysis of 29 patients was performed, including previously unpublished cases of surgically repaired LAEF from 4 institutions (n = 6), and all published cases of surgically repaired (n = 16) or stented (n = 7) LAEF., Results: The mean age was 55 ± 13 years, and 75% were men who were undergoing radiofrequency energy catheter ablation (n = 26), cryoablation (n = 1), high-intensity focused ultrasound ablation (n = 1), and surgical mini-MAZE procedure (n = 1) and presented 30 ± 12 days postablation procedure. Overall, 55% of the patients receiving an intervention for LAEF died (41% surgical repair; 100% stent). Patients who did not receive primary esophageal repair were more likely to experience postoperative complications, including mediastinitis, need for percutaneous endoscopic gastrostomy (PEG) feeds, esophageal stent, or death (P = .05). In addition, interposing tissue between the repaired esophagus and the left atrium resulted in fewer postoperative complications (P = .02)., Conclusions: While improved relative to initial reports, mortality associated with LAEF remains high after corrective intervention. Primary esophageal repair with the placement of tissue between the repaired esophagus and the left atrium may result in lower morbidity and mortality., (© 2013 Heart Rhythm Society. All rights reserved.)

Background: Hypertension is the most important risk factor directly attributable to the high prevalence of atrial fibrillation (AF), and is one of the few modifiable risk factors for AF. Activation and overactivity of the sympathetic nervous system (SNS) have been implicated in the pathogenesis of both essential hypertension and AF. Catheter-based renal sympathetic denervation (RSDN) appears to be an effective adjunctive treatment for refractory hypertension, and may be beneficial in other conditions characterized by SNS overactivity, such as left ventricular hypertrophy and atrial arrhythmias., Objective: The H-FIB study is a multicenter prospective, double-blind, randomized (1:1) controlled trial. The primary efficacy endpoint is antiarrhythmic drug-free freedom from AF recurrence through 12 months., Methods: Patients with a history of significant hypertension who are receiving treatment with at least one antihypertensive agent who are planned for a first time ablation for symptomatic paroxysmal or persistent AF will be randomized to either AF ablation alone (control group) or AF ablation + RSDN (study group)., Conclusions: H-FIB is a multicenter, randomized trial that will test the hypothesis that adjunctive renal sympathetic denervation, at the time of AF ablation, will increase the freedom from recurrent AF., (© 2013 Wiley Periodicals, Inc.)

Aims: The aim of the study was to assess the impact of isthmus location of atypical atrial flutters/atrial tachycardias (ATs) on outcomes of catheter ablation. Atrial tachycardias are clinically challenging arrhythmias that can occur in the presence of atrial scar--often due to either cardiac surgery or prior ablation for atrial fibrillation. We previously demonstrated a catheter ablation approach employing rapid multielectrode activation mapping with targeted entrainment manoeuvrs. However, the role that AT isthmus location plays in acute and long-term success of ablation remains uncertain., Methods and Results: Retrospective multicenter analysis of 91 consecutive AT patients undergoing ablation using a systematic four-step approach: (i) high-density activation mapping; (ii) analysis of atrial activation to identify wavefronts of electrical propagation; (iii) targeted entrainment of putative channels; and (iv) irrigated radiofrequency ablation of constrained regions of the circuit. Clinical outcomes, procedural details, and clinical profiles were determined. A total of 171 ATs (1.9 ± 1.0 per patient, 26% septal ATs) were targeted for ablation. The acute success rates were 97 and 77% for patients with either non-septal ATs or septal ATs, respectively (P = 0.0023). Similarly, the long-term success rates were 82 and 67% for patients with either no septal ATs or at least one septal AT, respectively (P = 0.1057). The long-term success rates were 75, 88, and 57% for patients with ATs associated with prior catheter ablation, cardiac surgery or MAZE, and idiopathic atrial scar, respectively., Conclusion: Catheter ablation of AT can be successfully performed employing a strategy of combined high-density activation and entrainment mapping. Septal ATs are associated with higher rates of acute and long-term recurrences.

Aims: Although complex fractionated atrial electrograms (CFAEs) are purported to represent critical sites for atrial fibrillation (AF) perpetuation, the mechanism and the significance of CFAE in the genesis of AF remain poorly understood. This study evaluated the relationship between CFAE and areas of abnormal atrial tissue defined by low-voltage electrograms (LVE) and signal average of the P-wave (SAPW)., Methods and Results: Complex fractionated atrial electrogram maps were obtained after pulmonary vein isolation in 15 patients with persistent AF. Patients were then cardioverted and voltage/activation maps were acquired in normal sinus rhythm (NSR). Total left atrium (LA), CFAE and LVE areas were measured as % of total LA area (mean ± SD). Conduction velocities of normal, LVE and CFAE areas were also measured during NSR. Patients underwent signal averaged ECG of the P-wave in NSR within 24 h of the procedure. Complex fractionated atrial electrograms areas accounted for 33 ± 24% of total LA. In NSR, only 12 ± 10% of LA area had LVE. There was no anatomic correlation between CFAE sites and LVE; the area of overlap between CFAE and LVE was only 1.6 ± 1.5%. Conduction velocity was faster in CFAE areas (2.3 ± 1.4 m/s) than in normal voltage areas (1.3 ± 0.3 m/s), and LVE areas (1.1 ± 0.7 m/s, P = 0.06). A positive correlation was only found between LVE areas and SAPW duration (r = 0.7, P = 0.04)., Conclusion: Areas of CFAEs correspond to areas of normal atrial voltage and normal conduction velocity during NSR. Complex fractionated atrial electrogram probably represents the response of normal healthy atrial tissue to rapid pulmonary vein activation.

Background: Percutaneous left ventricular assist devices (pLVADs) are increasingly being used to facilitate ablation of unstable ventricular tachycardia (VT), but the safety profile and hemodynamic benefits of these devices have not been described in a systematic, prospective manner., Methods and Results: Twenty patients with scar VT underwent ablation with a pLVAD. Neuromonitoring using cerebral oximetry was performed to evaluate a cerebral desaturation threshold to guide the duration of activation/entrainment mapping. The efficacy of pLVAD support was tested in a controlled manner with simulated VT. Complete procedural success was achieved in 50% (n=8) of patients, who were initially inducible for sustained VT, and partial procedural success in 37% (n=6). Using a cerebral desaturation level of 55% as a lower safety limit to guide the duration of sustained VT, 3 patients (15%) developed mild acute kidney injury (all resolved), and 1 (5%) patient developed mild cognitive dysfunction. During fast simulated VT (300 ms), cerebral desaturation to ≤55% occurred in more than half (53%) of patients tested without pLVAD support, compared with only 5% with full pLVAD support (P=0.003)., Conclusions: In a consecutive series of patients with severe left ventricular dysfunction, pLVAD-supported scar VT ablation was safe and feasible. During fast simulated VT, a miniaturized axial flow pump imparted a more favorable hemodynamic profile compared with pharmacological agents alone. Cerebral oximetry is a complimentary monitoring modality during scar VT ablation, and avoidance of cerebral desaturations below a threshold of 55% may safely guide the duration of mapping during unstable VT.

Background: Irrigated radiofrequency (RF) ablation can be insufficient to eliminate intramurally located septal atrial flutter (AFL) and ventricular tachycardia (VT) circuits. Bipolar ablation between 2 ablation catheters may be considered for such circuits., Objective: To evaluate the utility of bipolar irrigated ablation to terminate arrhythmias resistant to unipolar ablation., Methods: In vitro: Bipolar and sequential unipolar RF ablation lesions were placed on porcine ventricular tissue in a saline bath to assess for lesion transmurality. Clinical: 3 patients with atypical septal flutter (AFL), 4 patients with septal VT, and 2 with left ventricle free-wall VT, all of whom failed sequential unipolar RF ablation, underwent bipolar RF ablation using irrigated catheters placed on either surface of the interatria/interventricular septum and left ventricle free-wall, respectively., Results: In vitro: Bipolar RF was found to be more likely to achieve transmural lesions (82% vs 33%; P = .001) and could do so in tissues with thicknesses of up to 25 mm. Clinical: All 5 AFLs (3 patients) were successfully terminated with bipolar RF. In follow-up, AFL recurred in 2 of the 3 patients and atrial fibrillation and AFL recurred in 1 of the 3. All 3 thereafter underwent repeat procedures with successful maintenance of sinus rhythm in 2 of the 3 patients (6-month follow-up). In the VT subgroup, 5 of 6 septal VTs and 2 of 3 free-wall VTs were terminated successfully during ablation. In follow-up (12 months), 2 of the 4 patients in the septal bipolar group and 1 of the 2 patients in the free-wall group remained free of VT., Conclusions: Bipolar RF can be used to terminate arrhythmias in select patients with tachyarrhythmias., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: Temporary, ablation-mediated effects such as oedema may cause reversible pulmonary vein (PV) isolation. To investigate this, point-by-point circumferential ablation was performed to achieve acute electrical PV isolation with an incomplete circumferential ablation line. Then, the impact of this intentional 'visual gap' (ViG) on the conduction properties of the ablation lesion set was assessed with adenosine and pacing manoeuvres., Methods and Results: Twenty-eight patients undergoing ablation for paroxysmal (n= 20) or persistent atrial fibrillation (n= 8) were included. Pulmonary vein (PV) ablation was performed around ipsilateral vein pairs. Once acute isolation was achieved, ablation was halted and the presence and size of the ViG were calculated. The ViG electrophysiological properties were tested with pace capture along the ViG at 10 mA/2 ms, and assessment for dormant PV conduction with adenosine. Despite electrical isolation, a ViG was present in 75% (n= 42/56) of vein pairs (21 of 28 left PVs and 21 of 28 right PVs). There was no difference in the ViG size between the left and right PVs (22.1 ± 14.2 and 17.3 ± 11.3 mm, P > 0.05). Dormant PV connections were revealed by adenosine in more than a quarter (n= 12/42) of acutely isolated PV pairs, of which the majority were dependent on conduction through the ViG., Conclusions: Electrical PV isolation can usually be achieved without complete circumferential ablation. However, more than a quarter of these 'isolated' PVs exhibit dormant conduction-predominantly via the un-ablated 'ViGs' in the ablation lesion set. These findings support the hypothesis that reversible tissue injury contributes to PV isolation that may be acute but not necessarily durable.

Objective: To determine the feasibility and safety of esophageal displacement during atrial fibrillation (AF) ablation, to prevent thermal injury., Background: Patients undergoing AF ablation are at risk of esophageal thermal injury, which ranges from superficial ulceration, to gastroparesis, to the rare but catastrophic atrioesophageal fistula. A common approach to avoid damage is luminal esophageal temperature (LET) monitoring; however, (1) temperature rises mandate interruptions in energy delivery that interrupt workflow and potentially decrease procedural efficacy, and (2) esophageal fistulas have been reported even with LET monitoring., Methods: A cohort of 20 consecutive patients undergoing radiofrequency (RF) (16 patients) or laser balloon (4 patients) ablation of AF under general anesthesia. After barium instillation, the esophagus was deviated using an endotracheal stylet placed within a thoracic chest tube. LET monitoring was used during catheter ablation. Upper GI endoscopy was performed prior to discharge., Results: At the pulmonary vein level, leftward deviation measured 2.8 ± 1.6 cm (range: 0.4-5.7) and rightward deviation 2.8 ± 1.8 cm (range: 0.5-4.9). The temperature rose to >38.5 °C in 3/20 (15%) patients. In these 3 patients, there was an average of 2 applications/patient that recorded temperatures >38.5 °C. No patient had a temperature rise > 40 °C. Endoscopy revealed no esophageal ulceration from thermal injury in 18/19 (95%) patients; the sole patient with a thermally mediated ulceration had an unusual esophageal diverticulum fully across the posterior left atrium. Twelve patients (63%) exhibited trauma related to instrumentation with no clinical sequelae., Conclusions: Mechanical esophageal deviation is feasible and allows for uninterrupted energy delivery along the posterior wall during catheter ablation of AF., (© 2011 Wiley Periodicals, Inc.)