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Background: Catheter ablation atrial fibrillation (AF) is effective, but 20% to 40% of patients will require a repeat ablation. The role of more than 1 repeat ablation is not well known. Objectives: The purpose of this study was to evaluate the effectiveness and incremental benefits of multiple repeat catheter ablations to treat AF in patients. Methods: We retrospectively included patients who underwent their first, second, third, and fourth AF ablation between 2004 and 2019. They were monitored with a 24-to-48-hour Holter every 3 months postablation the first year and every 6 to 12 months thereafter. Recurrence was defined as documented atrial arrhythmia >30 seconds. Outcomes are analyzed by Kaplan-Meier curves and compared by log rank test. Results: We included a total of 2,194 patients (64% with paroxysmal and 36% with nonparoxysmal AF). Mean age was 71 ± 10 years; 67% were male. After 1 ablation, freedom from AF was 52%. Among those 1,052 patients who had recurrences, 576 (55%) underwent a second ablation, 103 (10%) underwent a third procedure, and 20 (2%) underwent a fourth. Success rates for the second, third, and fourth ablation were 57%, 60%, and 40%, respectively, at 5-year follow-up. After the second ablation, freedom from AF in our entire cohort increased from 52% to 66%, with marginal changes after the third (67%) and fourth (67%) procedures. Conclusions: Although repeated ablations demonstrated significant benefits at the individual level, the success rate may drop off after a third. The overall success of the initial cohort was not significantly influenced by the success rates of multiple follow-up ablations.

Background: Endocardial catheter ablation for ventricular tachycardia (VT) may fail because of the inability to deliver transmural lesions. Ultra-low–temperature cryoablation (ULTC) uses near-critical nitrogen and can generate temperatures as low as –196 °C. We report a series of 18 patients who underwent ULTC at the McGill University Health Centre (MUHC), representing the largest single-centre experience to date. Methods: Eighteen patients with monomorphic drug-refractory VT underwent VT ablation with ULTC at our institution as part of the first-in-human CryoCure-VT trial (NCT04893317). After voltage map, the mapping catheter was replaced with the ULTC catheter, and lesions were applied over a fixed duration of time (60-180 seconds), followed by a 60-second thaw and another application at the original duration (freeze-thaw-freeze). Duration of ablation time was selected depending on the wall thickness of the left ventricle monitored with intracardiac echo to achieve tissue depths of 4.5 to 7.5 mm. Results: Baseline left ventricular ejection fraction was 32%, mean age 71 years, 94% were male. A total of 32 sustained VTs were induced in 16 of 18 patients. A total of 177 cryoablation lesions were delivered (9.8 lesions per patient). Of the 16 patients with inducible VT, 15 (94%) were rendered noninducible postablation, and 1 was inducible only for a nonclinical VT. Complications included 1 pericardial effusion that required drainage. From 18 patients, 16 (89%) were discharged within the first 24 hours postablation. Conclusions: ULTC is feasible and permits acute control of monomorphic VT during VT ablation procedures in drug-refractory patients. Résumé: Contexte: L’ablation endocardique par cathéter pour traiter la tachycardie ventriculaire (TV) peut être un échec, en raison de l’incapacité à créer des lésions transmurales. La cryoablation à ultra-basse température (ULTC, pour ultra-low-temperature cryoablation) réalisée au moyen d’azote près de son point critique liquide-vapeur peut produire des températures aussi basses que –196 °C. Nous faisons état d’une série de 18 patients ayant subi une ULTC au Centre universitaire de santé McGill (CUSM), ce qui représente la plus importante expérience menée dans un seul établissement jusqu’à ce jour. Méthodologie: Au total, 18 patients atteints de TV monomorphe pharmacorésistante ont subi une ablation de la TV par ULTC à notre établissement, dans le cadre du premier essai mené chez l’humain sur la guérison par cryothérapie de la TV (NCT04893317). Après l’obtention de la carte électrophysiologique, le cathéter de cartographie a été remplacé par le cathéter d’ULTC, qui a permis de créer des lésions par l’application de froid pendant une durée fixe (de 60 à 180 secondes), suivie d’une période de dégel de 60 secondes, puis d’une autre application de froid pendant la même durée que la première application (cycle gel-dégel-gel). La durée de l’ablation a été déterminée en fonction de l’épaisseur de la paroi du ventricule gauche surveillée par échocardiographie endocavitaire afin d’obtenir des profondeurs tissulaires de 4,5 à 7,5 mm. Résultats: La fraction d’éjection du ventricule gauche initiale était de 32 %, l’âge moyen des sujets était de 71 ans et 94 % d’entre eux étaient de sexe masculin. Au total, 32 TV soutenues ont été induites chez 16 patients sur 18. Dans l’ensemble, 177 lésions de cryoablation ont été créées (soit 9,8 lésions par patient). Après l’ablation, nous avons été incapables d’induire une TV chez 15 (94 %) des 16 patients chez qui nous en avions induit avant l’intervention et, chez le patient restant, nous avons pu induire une TV non clinique seulement. Les complications comprenaient un cas d’épanchement péricardique ayant nécessité un drainage. Au total, 16 (89 %) des 18 patients ont reçu leur congé de l’hôpital dans les 24 heures suivant l’ablation. Conclusions: L’ULTC est réalisable et permet une maîtrise rigoureuse de la TV monomorphe lors des interventions d’ablation de la TV chez les patients dont la TV est pharmacorésistante.

Background: Cardioneuroablation (CNA) is an ablation technique that targets epicardial ganglionic plexi to reduce syncope burden and avoid pacemaker implantation in patients with cardioinhibitory vasovagal syncope (VVS). This study aims to demonstrate feasibility and safety of CNA in high-risk refractory VVS patients using continuous monitoring with an implantable loop recorder (ILR). Methods: Data was collected prospectively for patients undergoing CNA. Patients were required to have recurrent syncope with documented asystole, refractory to conservative measures. Ganglionic plexi (GPs) were identified by fragmented signals and high frequency stimulation (HFS). Ablation was performed until loss of positive response to HFS, Wenckebach cycle shortening was achieved, or an increase in sinus rate of > 20 bpm. Follow-up was performed through remote and clinic follow-up of their ILRs. Results: Between December 2020 and July 2023 six patients (mean age 29 ± 3, 67 % female)underwent CNA. The baseline heart rate and Wenckebach cycle length was 63.2 ± 15 bpm and 582 ms before and 91 ± 5 bpm and 358 ms after ablation respectively. During a median follow-up of 13.4 months, 3/5 patients had no further syncopal episodes, 1 had a recurrence, underwent repeat CNA with no further episodes at 1 year, and 1 had 5 syncopal events, which was a dramatic reduction from nearly daily episodes pre-CNA. There were no procedure related complications. Conclusions: A dramatic reduction in documented pauses and syncope burden was noted post CNA. Appropriate patient selection with rigorous objective follow-up in an experienced center is necessary. Larger studies are required to confirm these findings.

BackgroundSubstrate-based ablation has become a successful technique for ventricular tachycardia (VT) ablation. High-density (HD) mapping catheters provide high-resolution electroanatomical maps and better discrimination of local abnormal electrograms. The HD Grid Mapping Catheter is an HD catheter with the ability to map orthogonal signals on top of conventional bipolar signals, which could provide better discrimination of the arrhythmic substrate. On the other hand, conventional mapping techniques, such as activation mapping, when possible, help to identify the isthmus of the tachycardia.AimThe purpose of this study was to compare clinical outcomes after using two different VT ablation strategies: one based on extensive mapping with the HD Grid Mapping Catheter, including VT isthmus analysis, and the other based on pure substrate ablation.MethodsForty consecutive patients undergoing VT ablation with extensive HD mapping method in the hospital clinic (November 2018–November 2019) were included. Clinical outcomes were compared with a historical cohort of 26 consecutive patients who underwent ablation using a scar dechanneling technique before 2018.ResultsThe density of mapping points was higher in the extensive mapping group (2370.24 ± 920.78 vs. 576.45 ± 294.46; p < 0.001). After 1 year of follow-up, VT recurred in 18.4% of patients in the extensive mapping group vs. 34.6% of patients in the historical control group (p = 0.14), with a significantly greater reduction of VT burden: VT episodes (81.7 ± 7.79 vs. 43.4 ± 19.9%, p < 0.05), antitachycardia pacing (99.45 ± 2.29 vs. 33.9 ± 102.5%, p < 0.001), and implantable cardioverter defibrillator (ICD) shocks (99 ± 4.5 vs. 64.7 ± 59.9%, p = 0.02).ConclusionThe use of a method based on extensive mapping with the HD Grid Mapping Catheter and VT isthmus analysis allows better discrimination of the arrhythmic substrate and could be associated with a greater decrease in VT burden.

Background: The reported success rate of His-bundle pacing (HBP) in patients with infranodal atrioventricular (AV) conduction disease is only 52%-76%. The success rate of left bundle branch area pacing (LBBAP) in this cohort is not well studied.Objective: The purpose of this study was to evaluate the feasibility, safety, and electrophysiological characteristics of LBBAP in patients with AV conduction disease.Methods: Patients with AV conduction disease referred for pacemaker implantation at 2 centers between February 2019 and June 2021 were considered for LBBAP. Baseline demographic characteristics, procedural success rates, electrophysiological parameters, and complications were assessed.Results: LBBAP was successful in 340 of 364 patients (93%). Mean age was 72 ± 13 years, and mean follow-up was 331 ± 244 days. Pacing indications were Mobitz I in 27 patients (7%), Mobitz II or 2:1 AV block or high-grade AV block in 94 patients (26%), complete heart block in 199 patients (55%), and sick sinus syndrome with isolated bundle branch block in 44 patients (12%). Left bundle branch block and right bundle branch block were present in 57 patients (16%) and 140 patients (38%), respectively. Procedural success rates did not differ between indications (92.6%, 93.6%, 92.9%, and 95%, respectively) or between patients with narrow (<120 ms) vs wide QRS (≥120 ms). Mean LBBAP threshold was 0.77 ± 0.34 V at 0.4 ms at implant and remained stable during follow-up. There were 4 (1.2%) acute LBBAP lead dislodgments.Conclusion: LBBAP is safe and feasible with high success rates for patients with AV conduction disease. In contrast to HBP, LBBAP success rates remain high over the entire spectrum of AV conduction disease, and lead parameters remain stable during follow-up. [ABSTRACT FROM AUTHOR]

Background: Substrate-based ventricular tachycardia (VT) ablation is a first-line treatment in patients with structural cardiac disease and sustained VT refractory to medical therapy. Despite technological improvements and increased knowledge of VT substrate, recurrence still is frequent. Published data are lacking on the possible reduction in VT burden after ablation despite recurrence.Objective: The purpose of this study was to assess VT burden reduction during long-term follow-up after substrate ablation and identify predictors of VT recurrence.Methods: We analyzed 234 consecutive VT ablation procedures in 207 patients (age 63 ± 14.9 years; 92% male; ischemic heart disease in 65%) who underwent substrate ablation in a single center from 2013 to 2018.Results: After follow-up of 3.14 ± 1.8 years, the VT recurrence rate was 41.4%. Overall, a 99.6% reduction in VT burden (median VT episodes per year: preprocedural 3.546 [1.347-13.951] vs postprocedural 0.001 [0-0.689]; P = .001) and a 96.3% decrease in implantable cardioverter-defibrillator (ICD) shocks (preprocedural 1.145 [0.118-4.467] vs postprocedural 0.042 [0-0.111] per year; P = .017) were observed. In the subgroup of patients who experienced VT recurrences, VT burden decreased by 69.2% (median VT episodes per year: preprocedural 2.876 [1.105-8.801] vs postprocedural 0.882 [0.505-2.283]; P <.001). Multivariable analysis showed persistence of late potentials (67% vs 19%; hazard ratio 3.18 [2.18-6.65]; P <.001) and lower left ventricular ejection fraction (EF) (30 [25-40] vs 39 [30-50]; P = .022) as predictors of VT recurrence.Conclusion: Despite a high recurrence rate during long-term follow-up, substrate-based VT ablation is related to a large reduction in VT burden and a decrease in ICD therapies. Lower EF and persistence of late potentials are predictors of recurrence. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation atrial fibrillation (AF) is effective, but 20% to 40% of patients will require a repeat ablation. The role of more than 1 repeat ablation is not well known., Objectives: The purpose of this study was to evaluate the effectiveness and incremental benefits of multiple repeat catheter ablations to treat AF in patients., Methods: We retrospectively included patients who underwent their first, second, third, and fourth AF ablation between 2004 and 2019. They were monitored with a 24-to-48-hour Holter every 3 months postablation the first year and every 6 to 12 months thereafter. Recurrence was defined as documented atrial arrhythmia >30 seconds. Outcomes are analyzed by Kaplan-Meier curves and compared by log rank test., Results: We included a total of 2,194 patients (64% with paroxysmal and 36% with nonparoxysmal AF). Mean age was 71 ± 10 years; 67% were male. After 1 ablation, freedom from AF was 52%. Among those 1,052 patients who had recurrences, 576 (55%) underwent a second ablation, 103 (10%) underwent a third procedure, and 20 (2%) underwent a fourth. Success rates for the second, third, and fourth ablation were 57%, 60%, and 40%, respectively, at 5-year follow-up. After the second ablation, freedom from AF in our entire cohort increased from 52% to 66%, with marginal changes after the third (67%) and fourth (67%) procedures., Conclusions: Although repeated ablations demonstrated significant benefits at the individual level, the success rate may drop off after a third. The overall success of the initial cohort was not significantly influenced by the success rates of multiple follow-up ablations., Competing Interests: Dr Sanchez-Somonte was supported by a grant from La Fundación Alfonso Martín Escudero (Madrid, Spain). Dr Khaykin has received research grants from Biosense Webster and Medtronic. Dr Verma has received research grants from 10.13039/100004326Bayer, 10.13039/100007497Biosense Webster, 10.13039/501100005035Biotronik, 10.13039/100004374Medtronic, and Medlumics; has received compensation for advisory boards for Thermedical, Ablacon, Adagio Medical, Biosense Webster, Boston Scientific, Galaxy Medical, Medtronic, Medlumics, and Thermedical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Background: Cardioneuroablation (CNA) is an ablation technique that targets epicardial ganglionic plexi to reduce syncope burden and avoid pacemaker implantation in patients with cardioinhibitory vasovagal syncope (VVS). This study aims to demonstrate feasibility and safety of CNA in high-risk refractory VVS patients using continuous monitoring with an implantable loop recorder (ILR)., Methods: Data was collected prospectively for patients undergoing CNA. Patients were required to have recurrent syncope with documented asystole, refractory to conservative measures. Ganglionic plexi (GPs) were identified by fragmented signals and high frequency stimulation (HFS). Ablation was performed until loss of positive response to HFS, Wenckebach cycle shortening was achieved, or an increase in sinus rate of > 20 bpm. Follow-up was performed through remote and clinic follow-up of their ILRs., Results: Between December 2020 and July 2023 six patients (mean age 29 ± 3, 67 % female)underwent CNA. The baseline heart rate and Wenckebach cycle length was 63.2 ± 15 bpm and 582 ms before and 91 ± 5 bpm and 358 ms after ablation respectively. During a median follow-up of 13.4 months, 3/5 patients had no further syncopal episodes, 1 had a recurrence, underwent repeat CNA with no further episodes at 1 year, and 1 had 5 syncopal events, which was a dramatic reduction from nearly daily episodes pre-CNA. There were no procedure related complications., Conclusions: A dramatic reduction in documented pauses and syncope burden was noted post CNA. Appropriate patient selection with rigorous objective follow-up in an experienced center is necessary. Larger studies are required to confirm these findings., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Dr. Jacqueline Joza reports investigator-initiated external grant support from Medtronic Inc. and consulting fees from Boston Scientific (Modest)and honoraria from Biosense Webster Canada (Modest). Dr. Atul Verma receives grants or consultation funds from Biosense Webster, Medtronic, Bayer, Medlumics, Adagio Medical, and Boston Scientific. Dr. Vidal Essebag has received honoraria from Abbott, Biosense Webster, Boston Scientific, and Medtronic. The other authors have no disclosures related to this publication], (© 2024 The Author(s).)

Aims: Conducting channels (CCs) detected by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) are related to ventricular tachycardia (VT). The aim of this work was to study the ability of post-ablation LGE-CMR to evaluate ablation lesions., Methods and Results: This is a prospective study of consecutive patients referred for a scar-related VT ablation. LGE-CMR was performed 6-12 months prior to ablation and 3-6 months after ablation. Scar characteristics of pre- and post-ablation LGE-CMR were compared. During the study period (March 2019-April 2021), 61 consecutive patients underwent scar-related VT ablation after LGE-CMR. Overall, 12 patients were excluded (4 had poor-quality LGE-CMR, 2 died before post-ablation LGE-CMR, and 6 underwent post-ablation LGE-CMR 12 months after ablation). Finally, 49 patients (age: 65.5 ± 9.8 years, 97.9% male, left ventricular ejection fraction: 34.8 ± 10.4%, 87.7% ischaemic cardiomyopathy) were included. Post-ablation LGE-CMR showed a decrease in the number (3.34 ± 1.03 vs. 1.6 ± 0.2; P < 0.0001) and mass (8.45 ± 1.3 vs. 3.5 ± 0.6 g; P < 0.001) of CCs. Arrhythmogenic CCs disappeared in 74.4% of patients. Dark core was detected in 75.5% of patients, and its presence was not related to CC reduction (52.2 ± 7.4% vs. 40.8 ± 10.6%, P = 0.57). VT recurrence after one year follow-up was 16.3%. The presence of two or more channels in the post-ablation LGE-CMR was a predictor of VT recurrence (31.82% vs. 0%, P = 0.0038) with a sensibility of 100% and specificity of 61% (area under the curve 0.82). In the same line, a reduction of CCs < 55% had sensibility of 100% and specificity of 61% (area under the curve 0.83) to predict VT recurrence., Conclusion: Post-ablation LGE-CMR is feasible, and a reduction in the number of CCs is related with lower risk of VT recurrence. The dark core was not present in all patients. A decrease in VT substrate was also observed in patients without a dark core area in the post-ablation LGE-CMR., Competing Interests: Conflict of interest: L.M. and J.B. report activities as a consultant, lecturer, and advisory board member for Abbott Medical, Boston Scientific, Biosense Webster, Medtronic, and Biotronik. They are also shareholders of Adas3D Medical S.L. I.R.-L. and A.P.-S. have served as a consultant for Biosense Webster, Medtronic, Boston Scientific, and Abbott Medical. M.S. reports activities as a consultant, lecturer, advisory board member, and grant recipient for Abbott Medical, Edwards Lifesciences, Sanofi, General Electric, and Medtronic. All other authors report that they have no relationships relevant to the contents of this paper to disclose., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Endocardial catheter ablation for ventricular tachycardia (VT) may fail because of the inability to deliver transmural lesions. Ultra-low-temperature cryoablation (ULTC) uses near-critical nitrogen and can generate temperatures as low as -196 °C. We report a series of 18 patients who underwent ULTC at the McGill University Health Centre (MUHC), representing the largest single-centre experience to date., Methods: Eighteen patients with monomorphic drug-refractory VT underwent VT ablation with ULTC at our institution as part of the first-in-human CryoCure-VT trial (NCT04893317). After voltage map, the mapping catheter was replaced with the ULTC catheter, and lesions were applied over a fixed duration of time (60-180 seconds), followed by a 60-second thaw and another application at the original duration (freeze-thaw-freeze). Duration of ablation time was selected depending on the wall thickness of the left ventricle monitored with intracardiac echo to achieve tissue depths of 4.5 to 7.5 mm., Results: Baseline left ventricular ejection fraction was 32%, mean age 71 years, 94% were male. A total of 32 sustained VTs were induced in 16 of 18 patients. A total of 177 cryoablation lesions were delivered (9.8 lesions per patient). Of the 16 patients with inducible VT, 15 (94%) were rendered noninducible postablation, and 1 was inducible only for a nonclinical VT. Complications included 1 pericardial effusion that required drainage. From 18 patients, 16 (89%) were discharged within the first 24 hours postablation., Conclusions: ULTC is feasible and permits acute control of monomorphic VT during VT ablation procedures in drug-refractory patients., (© 2023 The Authors.)

Aims: Heterogeneous tissue channels (HTCs) detected by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) are related to ventricular arrhythmias, but there are few published data about their arrhythmogenic characteristics., Methods and Results: We enrolled 34 consecutive patients with ischaemic and non-ischaemic cardiomyopathy who were referred for ventricular tachycardia (VT) ablation. LGE-CMR was performed prior to ablation, and the HTCs were analyzed. Arrhythmogenic HTCs linked to induced VT were identified during the VT ablation procedure. The characteristics of arrhythmogenic HTCs were compared with those of non-arrhythmogenic HTCs. Three patients were excluded due to low-quality LGE-CMR images. A total of 87 HTCs were identified on LGE-CMR in 31 patients (age:63.8 ± 12.3 years; 96.8% male; left ventricular ejection fraction: 36.1 ± 10.7%). Of the 87 HTCs, only 31 were considered arrhythmogenic because of their relation to a VT isthmus. The HTCs related to a VT isthmus were longer [64.6 ± 49.4 vs. 32.9 ± 26.6 mm; OR: 1.02; 95% CI: (1.01-1.04); P < 0.001] and had greater mass [2.5 ± 2.2 vs. 1.2 ± 1.2 grams; OR: 1.62; 95% CI: (1.18-2.21); P < 0.001], a higher degree of protectedness [26.19 ± 19.2 vs. 10.74 ± 8.4; OR 1.09; 95% CI: (1.04-1.14); P < 0.001], higher transmurality [number of wall layers with CCs: 3.8 ± 2.4 vs. 2.4 ± 2.0; OR: 1.31; 95% CI: (1.07-1.60); P = 0.008] and more ramifications [3.8 ± 2.0 vs. 2.7 ± 1.1; OR: 1.59; 95% CI: (1.15-2.19); P = 0.002] than non-arrhythmogenic HTCs. Multivariate logistic regression analysis revealed that protectedness was the strongest predictor of arrhythmogenicity., Conclusion: The protectedness of an HTC identified by LGE-CMR is strongly related to its arrhythmogenicity during VT ablation., Competing Interests: Conflict of interest: I.R.L. and J.M.T. have served as consultants for Boston Scientific and Abbott Medical.L.M. and J.B. report activities as consultants, lecturers, and advisory board members for Abbott Medical, Boston Scientific, Biosense Webster, Medtronic, and Biotronik. They are also shareholders of Galgo Medical, S.L. M.S and R.FV work for ADAS3D Medical S.L. All other authors declare no conflict of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation ablation. Radiofrequency ablation has been the most common source of energy used to achieve PVI until now. In recent years, cryoballoon ablation has gained popularity due to its ability to perform PVI in a 'single-shot' fashion. In both cases (radiofrequency and cryoablation), the main limitation is their inability to achieve durable lesions without causing collateral damage to adjacent structures. In contrast, pulsed electric field (PEF) ablation is a non-thermal energy source that causes cell apoptosis by applying an electric current to the tissue. Lesions created by a field of energy seem to be more contiguous than traditional ablation, and the risk of damage to adjacent tissues is largely avoided due to the properties of the tissues and electrical fields. In recent years, new catheters capable of delivering PEF have been developed and are now undergoing clinical testing. In this article, we describe a complete solution for PVI: a single multielectrode catheter with 3D mapping capabilities that can deliver PEF in a single-shot PVI fashion with targeting beyond the pulmonary veins., Competing Interests: Disclosures: Paula Sanchez-Somonte is supported by a grant from La Fundación Alfonso Martín Escudero (Madrid, Spain). Atul Verma reports research grants from Bayer, Biosense Webster, Biotronik, Medtronic and Medlumics. He also receives compensation for advisory boards from Thermedical, Ablacon, Adagio Medical, Biosense Webster, Boston Scientific, Galaxy Medical, Medtronic, Medlumics and Thermedical., (© Touch Medical Media 2022.)

Background: Substrate-based ablation has become a successful technique for ventricular tachycardia (VT) ablation. High-density (HD) mapping catheters provide high-resolution electroanatomical maps and better discrimination of local abnormal electrograms. The HD Grid Mapping Catheter is an HD catheter with the ability to map orthogonal signals on top of conventional bipolar signals, which could provide better discrimination of the arrhythmic substrate. On the other hand, conventional mapping techniques, such as activation mapping, when possible, help to identify the isthmus of the tachycardia., Aim: The purpose of this study was to compare clinical outcomes after using two different VT ablation strategies: one based on extensive mapping with the HD Grid Mapping Catheter, including VT isthmus analysis, and the other based on pure substrate ablation., Methods: Forty consecutive patients undergoing VT ablation with extensive HD mapping method in the hospital clinic (November 2018-November 2019) were included. Clinical outcomes were compared with a historical cohort of 26 consecutive patients who underwent ablation using a scar dechanneling technique before 2018., Results: The density of mapping points was higher in the extensive mapping group (2370.24 ± 920.78 vs. 576.45 ± 294.46; p < 0.001). After 1 year of follow-up, VT recurred in 18.4% of patients in the extensive mapping group vs. 34.6% of patients in the historical control group ( p = 0.14), with a significantly greater reduction of VT burden: VT episodes (81.7 ± 7.79 vs. 43.4 ± 19.9%, p < 0.05), antitachycardia pacing (99.45 ± 2.29 vs. 33.9 ± 102.5%, p < 0.001), and implantable cardioverter defibrillator (ICD) shocks (99 ± 4.5 vs. 64.7 ± 59.9%, p = 0.02)., Conclusion: The use of a method based on extensive mapping with the HD Grid Mapping Catheter and VT isthmus analysis allows better discrimination of the arrhythmic substrate and could be associated with a greater decrease in VT burden., Competing Interests: LM, EA, JB, IR-L, and JT report activities as consultant, lecturer, and advisory board member for Abbott Medical, Boston Scientific, Biosense Webster, Medtronic, and Biotronik. MP-L has received honoraria from Medtronic. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Vázquez-Calvo, Garre, Sanchez-Somonte, Borras, Quinto, Caixal, Pujol-Lopez, Althoff, Guasch, Arbelo, Tolosana, Brugada, Mont and Roca-Luque.)

Ventricular tachycardia (VT) substrate-based ablation has become the gold standard treatment for patients with structural heart disease-related VT. VT is linked to re-entry in relation to myocardial scarring, with areas of conduction block (core scar) and of slow conduction (border zone). Slow conduction areas can be detected in sinus rhythm as late potentials (LPs). LP abolition has been shown to be the best end point to avoid long-term recurrences. Our study aimed to analyze the challenges of LP abolition and the predictors of failure. We analyzed 169 consecutive patients with structural heart disease (61% ischemic cardiomyopathy, left ventricular ejection fraction: 37 ± 13%) who underwent VT ablation between 2013 and 2018. A preprocedural clinical evaluation, including cardiac magnetic resonance, was done in 66% of patients. Electroanatomical mapping with the identification of LPs was performed in all patients. Noninducibility was achieved in 71% (119), and complete LP abolition was achieved in 61% (103) of patients. Incomplete LP abolition was a powerful predictor of VT recurrence (67% vs 33%, hazard ratio 3.19 [2.1 to 4.7]; p <0.001). Lack of use of a high-density mapping catheter (odds ratio 6.2, 1.2 to 38.1; p = 0.028), the septal substrate (odds ratio 9.34, 2.27 to 38.4; p = 0.002), and larger left ventricular mass (190 ± 58 g vs 156 ± 46 g, p = 0.002) were predictors of incomplete LP abolition. The main reasons that contributed to unsuccessful LP abolition were anatomic obstacles (such as the conduction system) and large extension of the LP area. In conclusion, incomplete LP abolition is related to VT recurrence. Lack of use of a high-density mapping catheter, the septal substrate, and larger left ventricular mass are related to incomplete LP abolition., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: To evaluate the safety and feasibility of left bundle branch area pacing (LBBAP) in patients with valvular interventions., Methods: Eighty-four patients were included in this study. All patients underwent recent surgical or percutaneous valvular interventions. LBBAP was attempted in all patients. Implant success rates, peri- and postprocedure electrocardiogram, pacing parameters, and complications were assessed at implant, and during follow-up., Results: LBBAP implantation was successful in 80/84 (95%) patients. Mean age was 74.1 ± 13.8 years and 56% patients were male. Prior valvular replacements included: percutaneous aortic (26), surgical aortic (36), combined surgical aortic plus mitral (6), MVR (10), tricuspid (1), and pulmonic (1). Average LVEF was 52.6 ± 11%. Majority of patients underwent LBBAP due to atrioventricular block (76%) and sinus node disease (13%). Total procedure duration was 74.1 ± 12.5 min and fluoroscopic duration was 9.7 ± 6.8 min. Pacing parameters were stable during follow-up period of 10.0 ± 6.3 months. Pacing QRS duration was significantly narrower than baseline QRS duration (131.5 ± 31.4 ms vs. 114.3 ± 13.7 ms, p < .001, respectively). No acute complications were observed. Mean follow-up was 10.0 ± 6.3 months (median: 8.4 months, min: 1 and max: 24 months). During follow-up, there were three device infections and two patients had loss of LBBA capture within 1 month of implant., Conclusions: LBBAP is a feasible and safe pacing modality in patients with prior interventions for valvular heart disease., (© 2021 Wiley Periodicals LLC.)

Objective: To evaluate the feasibility, safety, and clinical efficacy of non-fluoroscopic radiofrequency catheter ablation of atrial fibrillation (AF) in comparison to traditional fluoroscopy-guided ablation in a local Canadian community cohort., Methods: We retrospectively studied consecutive patients with paroxysmal and persistent AF undergoing pulmonary vein isolation (PVI) guided by intracardiac echocardiography (ICE) and Carto system (CartoSound module). ICE-guided PVI without fluoroscopy (Zero-fluoro group) was performed in 116 patients, and conventional fluoroscopy-guided PVI (Traditional group) was performed in 131 patients., Results: Two hundred and forty-seven patients with AF (60.7% male; mean age: 62.2 ± 10.6 years; paroxysmal AF =63.1%) who underwent PVI were studied. Mean procedure times were similar between both groups (136.8±33.4 minutes in the zero-fluoro group vs. 144.3±44.9 minutes in the traditional group; p=0.2). Acute PVI was achieved in all patients. Survival from early AF recurrence was 85% and 81% in the zero-fluoro and traditional groups, respectively (p = 0.06). Survival from late AF recurrence (12-months) between the zero-fluoro and traditional groups was also similar (p=0.1). Moreover, there were no significant differences between complication rates, including hematoma (p = 0.2) and tamponade (p = 1),between both groups., Conclusions: Zero-fluoroscopy ICE and CartoSound-guided AF ablation may be safe and feasible in patients undergoing PVI compared to conventional fluoroscopy-guided ablation.