Search

Competing Interests: Funding Support and Author Disclosures This work was supported by the Agence Nationale de la Recherche (grant no. IHU LIRYC ANR-10-IAHU-04). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Competing Interests: Funding Support and Author Disclosures This paper has been partly funded by Institut Hospitalo-Universitaire LIRYCInstitut Hospitalo-Universitaire LIRYC ANR-10-IAHU-04. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Competing Interests: The authors declare that there is no conflict of interest.

Competing Interests: Funding Support and Author Disclosures Supported by the Agence Nationale de la Recherche (grant no. IHU LIRYC ANR-10-IAHU-04). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Background: Atrial fibrillation (AF) and heart failure (HF) coexist, increasing morbidity and mortality. Studies have demonstrated improved outcomes following AF ablation in HF patients with reduced ejection fraction (EF)., Objective: This study sought to assess the outcomes of pulsed field ablation (PFA) in HF., Methods: MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a multicenter, patient-level registry of consecutive patients undergoing PFA for paroxysmal AF or persistent AF (PerAF). In this substudy, patients were stratified as no history of HF (no-HF), HF with preserved EF (HFpEF) (left ventricular EF of ≥50%) or HF with reduced/mildly reduced EF (HFmr/rEF) (left ventricular EF of <50%). The primary effectiveness and safety endpoints were freedom from documented atrial arrhythmias lasting ≥30 seconds and major adverse events, respectively., Results: Of the 1,381 patients, 85% (n = 1,174) were no-HF, 6.2% (n = 87) were HFpEF, and 8.6% (n = 120) were HFmr/rEF. No-HF patients had less PerAF than patients with HF (P < 0.001), with no difference between HF subtypes (P = >0.99). The 1-year freedom from atrial arrhythmia was significantly higher in no-HF patients than in those with HFpEF or HFmr/rEF (79.9%, 71.3%, and 67.5%, respectively; P < 0.001) but similar between patients with HFmr/rEF and HFpEF (P = 0.26). However, there was no significant difference in freedom from atrial arrhythmia among patients with no-HF vs HFpEF vs HFmr/rEF for those with paroxysmal AF (82.8%, 82.4%, and 71.7%, respectively; P = 0.09) and PerAF (73.3%, 64.2%, and 64.9%, respectively; P = 0.14). Major adverse event rates were similar between the no-HF, HFpEF, and HFmr/rEF groups (1.9%, 0%, and 2.5%, respectively)., Conclusions: PFA appears to be potentially safe and effective in AF patients with HF. Freedom from atrial arrhythmia post-PFA was higher in patients without a history of HF, with no significant difference between HF subtypes., Competing Interests: Funding Support and Author Disclosures Boston Scientific provided a grant to help fund data collection but was not otherwise involved with study design or analysis and did not have access to this manuscript before submission. Dr Turagam has received consulting fees from Biosense Webster, Boston Scientific Inc, and AltaThera and speaker honoraria from Sanofi and Medtronic. Dr Neuzil has received a grant from the Ministry of Health, Czech Republic, Development of Research Organizations (DRO), Na Homolka Hospital (NHH) (0023884). Dr Schmidt has received speaker fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. Dr Reichlin has received research grants from the Swiss National Science Foundation, the Swiss Heart Foundation, and the sitem insel support fund; speaker/consulting honoraria or travel support from Abbott/SJM, Bayer, Biosense Webster, Biotronik, Boston Scientific, Daiichi Sankyo, Medtronic, and Pfizer-BMS; and support for his institution’s fellowship program from Abbott/SJM, Biosense Webster, Biotronik, Boston Journal Pre-proof 21 Scientific, and Medtronic. Dr Neven has received speaker fees from Farapulse, Inc. Dr Metzner has received a research grant and fees from Farapulse. Dr Hansen has received speaker fees and grant support from Biosense Webster and Medtronic. Dr Blaauw has received research grants from Medtronic and Atricure and consulting fees from Abbott, Biosense Webster, Boston Scientific. Dr Sommer has served as a member of the Advisory Board for Abbott, Biosense Webster, Boston Scientific, and Medtronic. He has received modest honoraria from Medtronic. Dr Anic has received consultant fees from Farapulse Inc, Boston Scientific Inc, Galaxy Medical Inc, and Biosense Webster and has performed contracted research for Farapulse Inc, Boston Scientific Inc, Galaxy Medical Inc, and Biosense Webster. Dr Anselme has received consulting fees from Boston Scientific, Medtronic, and Microport CRM. Dr Boveda has received consulting fees from Medtronic, Boston Scientific, Microport, Zoll, and BMS. Dr Deneke has received speaker honoraria from Galaxy Medical, Abbott, and Biotronik, has been a consultant to Farapulse, and has served on a Clinical Events Committee for Boston Scientific. Dr Willems has received grants and personal fees from Abbott, Boston Scientific, and Medtronic and personal fees from Boehringer Ingelheim, Brystol Myers Squibb, Bayer Vital, Accutus, Daiichi, and Farapulse Inc. Dr Tilz has received consulting fees from Boston Scientific, Abbott Medical, Biotronik, and Biosense Webster and speaker honoraria from Boston Scientific, Abbott Medical, Biotronik, and Biosense Webster. Dr Scherr has received an educational grant from Farapulse Inc and is a consultant for Boston Scientific Inc. Dr Wakili has received investigator-initiated funding for research projects (initiated by him) from Bristol Myers Squibb, Pfizer, and Boston Scientific and speaking honoraria from Boston Scientific, Biotronik, and Medtronic. Dr Steven has received speaker fees from Pfizer, Bayer, Abbott, Johnson & Johnson, and Medtronic; grants from Abbott, Johnson & Johnson, and Boston Scientific; and consulting fees from Boston Scientific and Johnson & Johnson. Dr Kautzner has received personal fees from Bayer, Biosense Webster, Boehringer Ingelheim, Medtronic, and Abbott for participation in Scientific Advisory Boards and speaker honoraria from Bayer, Biosense Webster, Biotronik, Boehringer Ingelheim, CathVision, Medtronic, Mylan, Pfizer, ProMed, and Abbott. Dr Jais has received partial funding from L'institut Des Maladies Du Rythme Cardiaque, LIRYC ANR-10-IAHU-04, equity from Farapulse, and consulting fees and a grant from Boston Scientific. Dr Chun has received speaker fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. Dr Roten has received research grants from Medtronic, the Swiss National Foundation, the Swiss Heart Foundation, the Immanuel and Ilse Straub Foundation, and the Sitem Insel Support Fund and speaker fees/honoraria from Biosense Webster, Boston Scientific, Abbott, and Medtronic. Dr Lemoine has received a research grant from Farapulse. Dr Rollin has received a research grant from Farapulse. Dr Gunawardene has received grants from Farapulse Inc and Abbott. Dr Heeger has received travel grants and research grants from Boston Scientific, Lifetech, Biosense Webster, and Cardiofocus and speaker honoraria from Boston Scientific, Lifetech. Biosense Webster, Bayer, and Cardiofocus and he has served as a consultant for Medtronic, Journal Pre-proof 22 Lifetech, Boston Scientific, Biosense Webster, and Cardiofocus. Dr Manninger has received speaker fees from Bayer, Biosense Webster, Biotronik, Amomed, AOP Orphan, Boston Scientific, Daiichi Sankyo, and BMS/Pfizer and research grants from Biosense Webster and Abbott. Dr Sultan has received lecture and consulting honoraria from Medtronic, Abbott, and Bayer. Dr Derval has received receiving consulting fees from Boston Scientific. Dr Reddy has received consulting fees (and equity—now divested) from Farapulse Inc; has served as a consultant for Boston Scientific Inc; unrelated to this manuscript, has also served as a consultant for and has equity in Ablacon, Acutus Medical, Affera-Medtronic, Anumana, Apama Medical–Boston Scientific, APN Health, Aquaheart, Atacor, Autonomix, Axon Therapies, Backbeat, BioSig, CardiaCare, Cardiofocus, CardioNXT/AFTx, Circa Scientific, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNovA EP Technology, East End Medical, EPD-Philips, EP Frontiers, Epix Therapeutics–Medtronic, EpiEP, Eximo, Field Medical, Focused Therapeutics, HRT, Intershunt, Javelin, Kardium, Keystone Heart, Laminar Medical, LuxMed, Medlumics, Middlepeak, Neutrace, Nuvera–Biosense Webster, Oracle Health, Restore Medical, Sirona Medical, SoundCath, and Valcare; unrelated to this work, has served as a consultant for Abbott, Adagio Medical, Append Medical, AtriAN, Biosense Webster, BioTel Heart, Biotronik, Cairdac, Cardionomic, CoreMap, Fire1, Gore & Associates, Impulse Dynamics, Medtronic, Novartis, Novo Nordisk, Philips, Pulse Biosciences; and unrelated to this work, has equity in Atraverse, DRS Vascular, Manual Surgical Sciences, Newpace, Nyra Medical, Soundcath, Surecor, and Vizaramed. 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.)

Background: Atrial fibrillation (AF) and heart failure (HF) coexist, increasing morbidity and mortality. Studies have demonstrated improved outcomes following AF ablation in HF patients with reduced ejection fraction (EF)., Objective: To assess the outcomes of pulsed-field ablation (PFA) in HF., Methods: MANIFEST-PF is a multicenter patient-level registry of consecutive patients undergoing PFA for paroxysmal (PAF) or persistent AF (PerAF). In this sub-study, patients were stratified as: no history of HF (no-HF), HF with preserved EF (HF P EF; LVEF≥50%) or HF with reduced/mildly-reduced EF (HF MR/R EF; LVEF<50%). The primary effectiveness and safety endpoints were freedom from documented atrial arrhythmias lasting ≥30s and major adverse events (MAEs), respectively., Results: Of the 1,381 patients, 85% (n=1,174) were no-HF, 6.2% (n=87) were HF P EF, and 8.6% (n=120) were HF MR/R EF. No-HF patients had less PerAF than patients with HF (p<0.001), with no difference between HF subtypes (p=1.00). The 1-year freedom from atrial arrhythmia was significantly higher in no-HF than with HF P EF or HF MR/R EF (79.9%, 71.3%, 67.5%, p<0.001), but similar between HF MR/R EF and HF P EF (p=0.26). However, there was no significant difference in freedom from atrial arrhythmia among patients with no-HF vs HF P EF vs HF MR/R EF for those with PAF (82.8%/82.4%/71.7%, p=0.09) and PerAF (73.3%, 64.2%, and 64.9%, p=0.14.MAE rates were similar between the no-HF, HF P EF and HF MR/R EF groups (1.9%, 0%, and 2.5%, respectively)., Conclusion: PFA appears to be potentially safe and effective in AF patients with HF. Freedom from atrial arrhythmia post-PFA was higher in patients without a history of HF, with no significant difference between HF subtypes., (Copyright © 2024. Published by Elsevier Inc.)

Background: Pulmonary vein isolation (PVI) alone is insufficient to treat many patients with persistent atrial fibrillation (PersAF). Adjunctive left atrial posterior wall (LAPW) ablation with thermal technologies has revealed lack of efficacy, perhaps limited by the difficulty in achieving lesion durability amid concerns of esophageal injury., Objectives: This study aims to compare the safety and effectiveness of PVI + LAPW ablation vs PVI in patients with PersAF using pulsed-field ablation (PFA)., Methods: In a retrospective analysis of the MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-approval Clinical Use of Pulsed Field Ablation) registry, we studied consecutive PersAF patients undergoing post-approval treatment with a pentaspline PFA catheter. The primary effectiveness outcome was freedom from any atrial arrhythmia of ≥30 seconds. Safety outcomes included the composite of acute and chronic major adverse events., Results: Of the 547 patients with PersAF who underwent PFA, 131 (24%) received adjunctive LAPW ablation. Compared to PVI-alone, patients receiving adjunctive LAPW ablation were younger (65 vs 67 years of age, P = 0.08), had a lower CHA 2 DS 2 -VASc score (2.3 ± 1.6 vs 2.6 ± 1.6, P = 0.08), and were more likely to receive electroanatomical mapping (48.1% vs 39.0%, P = 0.07) and intracardiac echocardiography imaging (46.1% vs 17.1%, P < 0.001). The 1-year Kaplan-Meier estimate for freedom from atrial arrhythmias was not statistically different between groups in the full (PVI + LAPW: 66.4%; 95% CI: 57.6%-74.4% vs PVI: 73.1%; 95% CI: 68.5%-77.2%; P = 0.68) and propensity-matched cohorts (PVI + LAPW: 71.7% vs PVI: 68.5%; P = 0.34). There was also no significant difference in major adverse events between the groups (2.2% vs 1.4%, respectively, P = 0.51)., Conclusions: In patients with PersAF undergoing PFA, as compared to PVI-alone, adjunctive LAPW ablation did not improve freedom from atrial arrhythmia at 12 months., Competing Interests: Funding Support and Author Disclosures Boston Scientific provided a grant to help fund data collection but was not otherwise involved with study design or analysis nor did they have access to this manuscript before submission. Dr Turagam has received consulting fees from Biosense Webster; and has received speaker honorarium from Sanofi and Medtronic. Dr Neuzil has received grants from the Ministry of Health, Czech Republic, DRO (NHH, 00023884). Dr Schmidt has received speaker fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. Dr Reichlin has received grants from the Swiss National Science Foundation, the Swiss Heart Foundation, and the sitem insel support fund; has received speaker/consulting honoraria or travel support from Abbott/SJM, Bayer, Biosense Webster, Biotronik, Boston Scientific, Daiichi Sankyo, Medtronic, and Pfizer-BMS; and has received support for his institution’s fellowship program from Abbott/SJM, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. Dr Metzner has received grants and fees from Farapulse. Dr Hansen has received speaker fees and grant support from Biosense Webster and Medtronic. Dr Blaauw has received grants from Medtronic and Atricure; and has received consulting fees from Abbott, Biosense Webster, and Boston Scientific. Dr Sommer has been a member of the advisory boards for Abbott, Biosense Webster, Boston Scientific, and Medtronic. Dr Anic has received consultant fees from Farapulse Inc, Boston Scientific Inc, Galaxy Medical Inc, Biosense Webster; and has performed contracted research for Farapulse Inc, Boston Scientific Inc, Galaxy Medical Inc, and Biosense Webster. Dr Anselme has received consulting fees from Boston Scientific, Medtronic, and Microport CRM. Dr Boveda has received consulting fees from Medtronic, Boston Scientific, Microport, Zoll, and BMS. Dr Deneke has received speaker honoraria from Galaxy Medical, Abbott, and Biotronik; has received consulting fees from Farapulse; and has served on a Clinical Events Committee for Boston Scientific. Dr Willems has received grants and personal fees from Abbott, Boston Scientific, and Medtronic; and has received personal fees from Boehringer Ingelheim, Brystol Myers Squibb, Bayer Vital, Accutus, Daiichi, and Farapulse Inc. Dr Tilz reports receiving consulting fees from Boston Scientific, Abbott Medical, Biotronik, Biosense Webster and speaker honorarium from Boston Scientific, Abbott Medical, Biotronik, Biosense Webster. Dr Scherr has received an educational grant from Farapulse Inc; and is a consultant For Boston Scientific Inc. Dr Wakili has received consulting fees and travel expenses from Boston Scientific and Biotronik; has received investigator-initiated funding for research projects (initiated by him) from Bristol-Myers Squibb, Pfizer, and Boston Scientific; and has received speaking honoraria from Boston Scientific, Biotronik, and Medtronic. Dr Scherr has received speaking fees from Pfizer, Bayer, Abbott, Johnson & Johnson, and Medtronic; has received grants from Abbott, Johnson & Johnson, and Boston Scientific; and has received consulting fees from Boston Scientific and Johnson & Johnson. Dr Kautzner has received personal fees from Bayer, Biosense Webster, Boehringer Ingelheim, Medtronic, and Abbott for participation in scientific advisory boards; and has received speaker honoraria from Bayer, Biosense Webster, Biotronik, Boehringer Ingelheim, CathVision, Medtronic, Mylan, Pfizer, ProMed, and Abbott. Dr Jais has received partial funding from IHU LIRYC ANR-10-IAHU-04; has received equity from Farapulse; and has received consulting fees and grants from Boston Scientific. Dr Chun has received speaker fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. Dr Roten has received speaker honoraria from Abbott/SJM; has received consulting honoraria from Medtronic; and has received research funding to the institution from Medtronic. Dr Lemoine has received grants from Farapulse. Dr Rollin has received grants from Farapulse. Dr Nentwich has received speaker fees from Farapulse, Inc. Dr Gunawardine has received grants from Farapulse Inc and Abbott. Dr Heeger has received travel grants and research grants from Boston Scientific, Lifetech, Biosense Webster, and Cardiofocus; has received speaker honoraria from Boston Scientific, Lifetech, Biosense Webster, Bayer, and Cardiofocus; and has received consulting fees from Medtronic, Lifetech, Boston Scientific, Biosense Webster, and Cardiofocus. Dr Manninger has received speaker fees from Bayer, Biosense Webster, Biotronik, Amomed, AOP Orphan, Boston Scientific, Daiichi Sankyo, and BMS/Pfizer; and has received grants from Biosense Webster and Abbott. Dr Sultan has received lecture and consulting honoraria from Medtronic, Abbott, and Bayer. Dr Derval has received consulting fees from Boston Scientific. Dr Reddy has received consulting fees (and equity – now divested) from Farapulse Inc; has received consulting fees from Boston Scientific Inc; and, unrelated to this manuscript, has served as a consultant for and has equity in Ablacon, Acutus Medical, Affera-Medtronic, Apama Medical-Boston Scientific, Anumana, APN Health, Aquaheart, Atacor, Autonomix, Axon Therapies, Backbeat, BioSig, CardiaCare, CardioNXT/AFTx, Circa Scientific, CoRISMA, Corvia Medical, Dinova-Hangzhou DiNovA EP Technology, East End Medical, EPD-Philips, EP Frontiers, Epix Therapeutics-Medtronic, EpiEP, Eximo, Field Medical, Focused Therapeutics, HRT, Intershunt, Javelin, Kardium, Keystone Heart, Laminar, LuxMed, Medlumics, Middlepeak, Neutrace, Nuvera-Biosense Webster, Oracle Health, Restore Medical, Sirona Medical, SoundCath, Valcare; also unrelated to this work, he has received consulting fees from AtriAN, Biosense-Webster, BioTel Heart, Biotronik, Cairdac, Cardiofocus, Cardionomic, CoreMap, Fire1, Gore & Associates, Impulse Dynamics, Medtronic, Novartis, Philips, and Pulse Biosciences; and he has equity in Manual Surgical Sciences, Newpace, Nyra Medical, Surecor, and Vizaramed. 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: None.

Background: Substrate abnormalities can alter atrial activation during atrial tachycardias (ATs) thereby influencing AT-wave morphology on the surface electrocardiogram., Objectives: This study sought to identify determinants of isoelectric intervals during ATs with complex atrial activation patterns., Methods: High-density activation maps of 126 ATs were studied. To assess the impact of the activated atrial surface on the presence of isoelectric intervals, this study measured the minimum activated area throughout the AT cycle, defined as the smallest activated area within a 50-millisecond period, by using signal processing algorithms (LUMIPOINT)., Results: ATs with isoelectric intervals (P-wave ATs) included 23 macro-re-entrant ATs (40%), 26 localized-re-entrant ATs (46%), and 8 focal ATs (14%), whereas those without included 46 macro-re-entrant ATs (67%), 21 localized-re-entrant ATs (30%), and 2 focal ATs (3%). Multivariable regression identified smaller minimum activated area and larger very low voltage area as independent predictors of P-wave ATs (OR: 0.732; 95% CI: 0.644-0.831; P < 0.001; and OR: 1.042; 95% CI: 1.006-1.080; P = 0.023, respectively). The minimum activated area with the cutoff value of 10 cm 2 provided the highest predictive accuracy for P-wave ATs with sensitivity, specificity, and positive and negative predictive values of 96%, 97%, 97%, and 95%, respectively. In re-entrant ATs, smaller minimum activated area was associated with lower minimum conduction velocity within the circuit and fewer areas of delayed conduction outside of the circuit (standardized β: 0.524; 95% CI: 0.373-0.675; P < 0.001; and standardized β: 0.353; 95% CI: 0.198-0.508; P < 0.001, respectively)., Conclusions: Reduced atrial activation area and voltage were associated with isoelectric intervals during ATs., Competing Interests: Funding Support and Author Disclosures This research was partly funded by a grant from Investissement d’avenir: IHU LIRYC ANR-10-IAHU-04. Ms Carapezzi is an employee of Boston Scientific. Dr Jaïs has received speaking honoraria and consulting fees from Boston Scientific. 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.)

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.

Objectives: This study sought to introduce a computed tomography (CT) protocol for optimal planning of vein of Marshall (VOM) catheterization., Background: Ethanol infusion into the VOM (Et-VOM) is increasingly used in atrial fibrillation ablation., Methods: Preprocedural CT was performed with either a conventional (conv-CT; n = 132) or an optimized CT protocol (VOM-CT; n = 126) designed for obtaining on a single image both left atrial and coronary sinus (CS) enhancement. The detection rate and anatomical features of the CT-derived VOM were analyzed and the utility of VOM-CT protocol was assessed by comparing the procedural data., Results: VOM was detected in 35% in conv-CT versus 63% in VOM-CT (P < 0.001). The VOM-CT protocol did not impair the assessment of left atrial anatomy and appendage patency. In VOM-CT, the detection of the VOM was related to body mass index and width of epicardial space on posterior wall. Mean distance between CS ostium and VOM was 36 ± 7 mm. Mean VOM diameter was 1.6 ± 0.3 mm. On the CS circumference, the VOM emerged superiorly in 68% and postero-superiorly in 32%. Ethanol infusion into the VOM was attempted in 165 patients (77 conv-CT, 70 VOM-CT, and 18 without-CT). After registration in CARTO, the VOM segmented on CT matched its location on venography in all cases. As compared with conv-CT and without-CT, procedures guided by VOM-CT showed significantly shorter radiation time, shorter procedure time, lower amount of the contrast medium, and fewer contrast injections to obtain VOM catheterization., Conclusions: The proposed CT protocol allows for improved visualization of the VOM, translating into easier VOM catheterization., Competing Interests: Funding Support and Author Disclosures Support was provided by the French National Agency for Research, Equipex-MUSIC ANR-11-EQPX-0030, and IHU-LIRYC ANR-10-IAHU-04. Drs Derval, Pambrun, Duchateau, and Sacher have received consulting fees and speaking honoraria from Biosense Webster. Drs Derval, Sacher, and Jaïs have received speaking honoraria from Boston Scientific. 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 systematically evaluated mechanisms of atrial tachycardia (AT) by using ultra-high-resolution mapping in a large cohort of patients., Background: An incomplete understanding of the mechanism of AT is a major determinant of ablation failure., Methods: Consecutive patients with ≥1 AT (excluding cavotricuspid isthmus-dependent flutter) were included. Mapping was performed with a 64-pole mapping catheter. The AT mechanism was defined based on activation mapping and confirmed by entrainment in selected cases., Results: A total of 132 patients were included (60 ± 12 years; 31 [23%] female; 111 [84%] previous atrial fibrillation [AF] ablation; 5 [4%] previous left atriotomy). One hundred four (94%) of the 111 post-AF ablation AT patients had substrate-based ablation during the index AF ablation. A total of 214 ATs were mapped, with complete definition of the AT mechanism in 206 (96%). A total of 129 (60%) had anatomic macro-re-entry (circuit diameter 44.2 ± 9.6 mm), 57 (27%) had scar-related localized re-entry (circuit diameter 25.8 ± 12.2 mm), and 20 (9%) had focal AT. Fifty-eight (45%) patients had multiple ATs (27 [20%] dual-loop re-entry; 60 [43%] sequential AT) with complex and highly variable transitions between AT circuits. A total of 116 (90%) of 129 macro-re-entrant ATs, 56 (98%) of 57 localized AT, and 20 (100%) of 20 focal ATs terminated after radiofrequency ablation. After a mean follow-up of 13 ± 9 months, 57 (46%) patients experienced recurrence of AT., Conclusions: Among patients with AT in the context of previous atrial interventions, particularly post-AF ablation patients, multiple complex AT circuits are common. Despite complete delineation of arrhythmia circuits using ultra-high-resolution mapping and high acute ablation success rates, long-term freedom from AT is modest., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Idiopathic ventricular fibrillation is diagnosed in patients who survived a ventricular fibrillation episode without any identifiable structural or electrical cause after extensive investigations. It is a common cause of sudden death in young adults. The study reviews the diagnostic value of systematic investigations and the new insights provided by detailed electrophysiological mapping. Recent studies have shown the high incidence of microstructural cardiomyopathic areas, which act as the substrate of ventricular fibrillation re-entries. These subclinical alterations require high-density endo- and epicardial mapping to be identified using electrogram criteria. Small areas are involved and located individually in various sites (mostly epicardial). Their characteristics suggest a variety of genetic or acquired pathological processes affecting cellular connectivity or tissue structure, such as cardiomyopathies, myocarditis, or fatty infiltration. Purkinje abnormalities manifesting as triggering ectopy or providing a substrate for re-entry represent a second important cause. The documentation of ephemeral Purkinje ectopy requires continuous electrocardiography monitoring for diagnosis. A variety of diseases affecting Purkinje cell function or conduction are potentially at play in their pathogenesis. Comprehensive investigations can therefore allow the great majority of idiopathic ventricular fibrillation to ultimately receive diagnoses of a cardiac disease, likely underlain by a mosaic of pathologies. Precise phenotypic characterization has significant implications for interpretation of genetic variants, the risk assessment, and individual therapy. Future improvements in imaging or electrophysiological methods may hopefully allow the identification of the subjects at risk and the development of primary prevention strategies., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: A new electroanatomic mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) using a 64-electrode mapping basket is now available; we systematically assessed its use in complex congenital heart disease (CHD)., Background: The incidence of atrial arrhythmias post-surgery for CHD is high. Catheter ablation has emerged as an effective treatment, but is hampered by limitations in the mapping system's ability to accurately define the tachycardia circuit., Methods: Mapping and ablation data of 61 patients with CHD (35 males, age 45 ± 14 years) from 8 tertiary centers were reviewed., Results: Causes were as follows: Transposition of Great Arteries (atrial switch) (n = 7); univentricular physiology (Fontans) (n = 8); Tetralogy of Fallot (n = 10); atrial septal defect (ASD) repair (n = 15); tricuspid valve (TV) anomalies (n = 10); and other (n = 11). The total number of atrial arrhythmias was 86. Circuits were predominantly around the tricuspid valve (n = 37), atriotomy scar (n = 10), or ASD patch (n = 4). Although the majority of peri-tricuspid circuits were cavo-tricuspid-isthmus dependent (n = 30), they could follow a complex route between the annulus and septal resection, ASD patch, coronary sinus, or atriotomy. Immediate ablation success was achieved in all but 2 cases; with follow-up of 12 ± 8 months, 7 patients had recurrence., Conclusions: We demonstrate the feasibility of the basket catheter for mapping complex CHD arrhythmias, including with transbaffle and transhepatic access. Although the circuits often involve predictable anatomic landmarks, the precise critical isthmus is often difficult to predict empirically. Ultra-high-density mapping enables elucidation of circuits in this complex anatomy and allows successful treatment at the isthmus with a minimal lesion set., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to identify atrial tachycardia (AT) demonstrating atrial activation duration (AAD) lasting longer than the length of the tachycardia cycle (TCL); to assess AT prevalence; and to evaluate the mechanisms and characteristics associated with these AT episodes by using the Rhythmia system (Boston Scientific, Marlborough, Massachusetts)., Background: Ultra-high-density mapping allows very accurate characterization of mechanisms involved in AT. Some complex patterns may involve AAD which is longer than the tachycardia cycle length (TCL) which makes maps difficult to interpret. Prevalence and characteristics of such ATs are unknown., Methods: A cohort of 100 consecutive patients undergoing ablation of 125 right (n = 21) or left (n = 104) ATs using ultra-high-density mapping were retrospectively included. Offline calculation of right or left AAD was compared to TCL., Results: Mean TCL was 293 ± 65 ms, and mean AAD was 291 ± 74 ms (p = NS). AT mechanisms were macro-re-entry in 74 cases (59%), localized re-entry in 27 cases (22%), and focal AT in 21 cases (17%) (types were mixed in 3 cases). Fifteen ATs (12%) had AADs that were longer than the TCL (71 ± 45 ms longer, from 10 to 150 ms). TCL was equal to the AAD in 97 ATs (78%), whereas 13 ATs (10%) had AAD shorter than the TCL (focal AT in each case). There were no differences between right and left atria for prevalence of ATs with AADs that were longer than the TCLs. There were significant differences in AT mechanisms according to the AAD-to-TCL ratio (p < 0.0001), with localized re-entry showing more often that AAD was longer than the TCL compared to that in focal AT and macro-re-entry., Conclusions: ATs with AAD lasting longer than the TCL were present in approximately 10% of the ATs referred for ablation, mostly in ATs caused by localized re-entry. Ultra-high-density mapping allows detection of these complex patterns of activation., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study reports the use of a novel "Lumipoint" algorithm in ventricular tachycardia (VT) ablation., Background: Automatic mapping systems aid rapid acquisition of activation maps. However, they may annotate farfield rather than nearfield signal in low voltage areas, making maps difficult to interpret. The Lumipoint algorithm analyzes the complete electrogram tracing and therefore includes nearfield signals in its analysis., Methods: Twenty-two patients with ischemic cardiomyopathy and 5 with dilated cardiomyopathy underwent mapping using the ultra-high density Rhythmia system. Lumipoint algorithms were applied retrospectively., Results: In all left ventricular substrate maps, changing the window of interest to the post-QRS phase automatically identified late potentials. In 25 of 27 left ventricular VT activation maps, a minimum spatial window of interest correctly identified the VT isthmus as seen by the manually annotated map, entrainment, and response to ablation. In 6 maps, the algorithm identified the isthmus where the standard automatically annotated map did not., Conclusions: The Lumipoint algorithm automatically highlights areas with electrograms having specific characteristics or timings. This can identify late and fractionated potentials and regions that exhibit discontinuous activation, as well as the isthmus of a VT circuit. These features may enhance human interpretation of the electrogram signals during a case, particularly where the circuit lies in partial scar with low amplitude nearfield signals and potentially allow a more targeted ablation strategy., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to evaluate the relation between bipolar electrode spacing and far- and near-field electrograms., Background: The detailed effects of bipolar spacing on electrograms (EGMs) is not well described., Methods: With a HD-Grid catheter, EGMs from different bipole pairs could be created in each acquisition. This study analyzed the effect of bipolar spacing on EGMs in 7 infarcted sheep. A segment was defined as a 2-mm center-to-center bipole. In total, 4,768 segments (2,020 healthy, 1,542 scar, and 1,206 in border areas, as defined by magnetic resonance imaging [MRI]) were covered with an electrode pair of spacing of 2 mm (Bi-2), 4 mm (Bi-4), and 8 mm (Bi-8)., Results: A total of 3,591 segments in Bi-2 were free from local abnormal ventricular activities (LAVAs); 1,630 segments were within the MRI-defined scar and/or border area. Among them, 172 (10.6%) segments in Bi-4 and 219 (13.4%) segments in Bi-8 showed LAVAs. In contrast, LAVAs were identified in 1,177 segments in Bi-2; 1,118 segments were within the MRI-defined scar and/or border area. Among them, LAVAs were missed in 161 (14.4%) segments in Bi-4 and in 409 (36.6%) segments in Bi-8. In segments with LAVAs, median far-field voltage increased from 0.09 mV (25th to 75th percentile: 0.06 to 0.14 mV) in Bi-2, to 0.16 mV (25th to 75th percentile: 0.10 to 0.24 mV) in Bi-4, and to 0.28 mV (25th to 75th percentile: 0.20 to 0.42 mV) in Bi-8 (p < 0.0001). Median near-field voltage increased from 0.14 mV (25th to 75th percentile: 0.08 to 0.25 mV) in Bi-2, to 0.21 mV (25th to 75th percentile: 0.12 to 0.35 mV) in Bi-4, and to 0.32 mV (25th to 75th percentile: 0.17 to 0.48 mV) in Bi-8 (p < 0.0001). The median near-/far-field voltage ratio decreased from 1.67 in Bi-2, to 1.43 in Bi-4, and 1.23 in Bi-8 (p < 0.0001)., Conclusions: Closer spacing better discriminates surviving tissue from dead scar area. Although far-field voltage systematically increases with spacing, near-field voltages were more variable, depending on local surviving muscular bundles. Near-field EGMs are more easily observed with smaller spacing, largely due to the reduction of the far-field effect., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study evaluated a new algorithm relying on maximal pre-excitation., Background: Prior knowledge of accessory pathway (AP) location facilitates an individual ablation strategy. Delta-wave analysis on a 12-lead electrocardiogram is recognized as crucial for predicting ablation site, but can be ambiguous at basal state., Methods: An algorithm based on maximal pre-excitation, as induced by atrial pacing during an electrophysiological study, was initially developed in 132 patients with a single manifest AP. The maximally pre-excited QRS features included the global polarity in lead V 1 (step 1), inferior leads (step 2), and leads V 3 or I (step 3), as well as the morphology in lead II (step 4). Three investigators prospectively tested the new algorithm in 207 consecutive patients by comparing its efficacy to a control algorithm relying on basal pre-excitation., Results: The accuracy, defined as the percent of patients with an exact prediction of AP location, was significantly greater with the new algorithm (90% vs. 63%; p < 0.001). The reproducibility, defined as the level of agreement between investigators in determining AP location, was excellent (κ > 0.75; p < 0.05) with the new algorithm and fair (0.40 < κ < 0.75; p < 0.05) with the control algorithm., Conclusions: An algorithm based on maximal pre-excitation allows accurate and reproducible localization of manifest APs. When ablation is indicated, the analysis of maximal pre-excitation is a sensible approach for giving a head start in endocardial mapping., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to assess the relationship between fibrosis and re-entrant activity in persistent atrial fibrillation (AF)., Background: The mechanisms involved in sustaining re-entrant activity during AF are poorly understood., Methods: Forty-one patients with persistent AF (age 56 ± 12 years; 6 women) were evaluated. High-resolution electrocardiographic imaging (ECGI) was performed during AF by using a 252-chest electrode array, and phase mapping was applied to locate re-entrant activity. Sites of high re-entrant activity were defined as re-entrant regions. Late gadolinium-enhanced (LGE) cardiac magnetic resonance (CMR) was performed at 1.25 × 1.25 × 2.5 mm resolution to characterize atrial fibrosis and measure atrial volumes. The relationship between LGE burden and the number of re-entrant regions was analyzed. Local LGE density was computed and characterized at re-entrant sites. All patients underwent catheter ablation targeting re-entrant regions, the procedural endpoint being AF termination. Clinical, CMR, and ECGI predictors of acute procedural success were then analyzed., Results: Left atrial (LA) LGE burden was 22.1 ± 5.9% of the wall, and LA volume was 74 ± 21 ml/m 2 . The number of re-entrant regions was 4.3 ± 1.7 per patient. LA LGE imaging was significantly associated with the number of re-entrant regions (R = 0.52, p = 0.001), LA volume (R = 0.62, p < 0.0001), and AF duration (R = 0.54, p = 0.0007). Regional analysis demonstrated a clustering of re-entrant activity at LGE borders. Areas with high re-entrant activity showed higher local LGE density as compared with the remaining atrial areas (p < 0.0001). Failure to achieve AF termination during ablation was associated with higher LA LGE burden (p < 0.001), higher number of re-entrant regions (p < 0.001), and longer AF duration (p = 0.008)., Conclusions: The number of re-entrant regions during AF relates to the extent of LGE on CMR, with the location of these regions clustering to LGE areas. These characteristics affect procedural outcomes of ablation.

Objectives: The purpose of this study was to describe and identify useful electrocardiographic characteristics to help identify the mechanism of atrial tachycardia (AT) occurring after persistent atrial fibrillation (PsAF) ablation., Background: Electrocardiographic analysis to help identify the mechanism of AT after PsAF ablation is much limited by the fact that remodeling and ablation alter the normal activation pattern., Methods: All consecutive patients who underwent mapping and ablation of AT after PsAF ablation were included. Surface P waves were analyzed during higher (>2:1) grades of atrioventricular block., Results: One hundred ninety-six ATs with visible P waves were identified in 127 patients (macro-re-entry in 57%, centrifugal AT in 43%). One-third displayed low-voltage P waves (≤0.1 mV). An isoelectric line >80 ms was more common in centrifugal compared with macro-re-entrant AT (47% vs. 24%; p < 0.001), but its positive predictive value was limited (60%). A minority of peritricuspid ATs displayed the classic saw-tooth pattern (27% [n = 22]). However, the "precordial transition" (a gradual transition from an upright component in lead V 1 to a negative component with progression across the precordium) remained often observed and specifically identified peritricuspid AT (specificity, 98%; sensitivity, 59%). Only 2 unique features could help identify perimitral AT (n = 60). First, the presence of a negative or negative-positive P-wave in any of leads V 2 to V 6 identified perimitral AT with 97% specificity and 30% sensitivity. Second, a "notched" negative component at the beginning of a positive P-wave in the inferior leads specifically identified clockwise perimitral AT (specificity, 98%; sensitivity, 25%)., Conclusions: Only few unique electrocardiographic characteristics help identify the mechanism of AT after PsAF ablation. Knowledge of these characteristics may aid in planning and performing ablation., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: Using high-resolution 3-dimensional (3D) mapping, the aim of this study was to further characterize right atrial macro-re-entrant tachycardias and answer unresolved questions in the understanding of this arrhythmia., Background: Despite advances in understanding of the mechanisms of right atrial macro-re-entrant tachycardias, many questions lack definitive answers. The advent of high-resolution 3D mapping provides an opportunity to gain further insights into the nature of these common circuits., Methods: A total of 25 patients with right atrial macro-re-entrant tachycardia were studied. High-resolution 3D mapping (Rhythmia mapping system, Boston Scientific, Natick, Massachusetts) was performed. Regional voltage and conduction velocity were determined. Maps were analyzed to characterize wave front propagation patterns in all atrial regions. The relationship between substrate and conduction was evaluated., Results: A total of 42 right atrial macro-re-entrant circuits were observed. The most common location of the posterior line of block was the posteromedial right atrium (73%). This line of block continued superiorly into the superior vena cava, taking an oblique course to finish on the anterior superior vena cava aspect in 73%. Conduction delay at the crista terminalis was less common (23%). Conduction slowing or block was seen at the limbus of the fossa ovalis (73%) and Eustachian ridge (77%). Highly variable and localized areas of slow conduction were also observed in the inferior septum (45%), superior septum (27%), anterosuperior right atrium (23%), and lateral right atrium (23%). Localized conduction slowing was seen in the cavotricuspid isthmus in 50% of patients, but there was no generalized conduction slowing in this isthmus. The voltage in regions of slow conduction was significantly lower compared with areas of normal conduction velocity (p < 0.001). Conduction channels were observed in 55% of patients., Conclusions: High-resolution 3D mapping has provided new insights into the nature of right atrial macro-re-entrant tachycardias. Variable regions of abnormal atrial substrate were associated with conduction slowing and block. Individual variation in propagation patterns was observed in association with this variable substrate. (Mapping of Atrial Arrhythmias Using High Spatial Resolution Mapping Catheters and the Rhythmia Mapping System; ACTRN12615000544572)., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to characterize the clinical characteristics, atrial substrate, and prognosis in a subgroup of patients with persistent atrial fibrillation (AF) from the onset (PsAFonset)., Background: Patients with AF frequently progress from trigger-driven paroxysmal arrhythmias to substrate-dependent persistent arrhythmias., Methods: Patients referred for persistent AF (PsAF) ablation were enrolled from 3 centers. Consecutive patients with PsAFonset (n = 129) were compared with patients with PsAF that progressed from paroxysmal AF (n = 231). In addition, 90 patients (30 patients with PsAFonset and 60 control subjects) were studied with noninvasive mapping to characterize the AF drivers. The degree of fractionation and endocardial voltages were assessed invasively., Results: Patients with PsAFonset were younger (p = 0.047) and more obese (p < 0.001); there were more men (p = 0.034), more patients with hypertension (p = 0.044), and these patients had larger left (p < 0.05) and right atria (p < 0.05). Baseline AF cycle length was shorter in the PsAFonset group (p < 0.01); the degree of fractionation was higher (p < 0.001 for both atria), and the endocardial voltage was lower (p < 0.05 for both atria). Patients with PsAFonset had higher a number of re-entrant driver regions (p < 0.001) and extrapulmonary vein regions that had re-entrant drivers (p < 0.05), whereas control subjects displayed more focal driver regions (p = 0.029). The acute AF termination rate was lower in the PsAFonset group (42% vs. 81%; p < 0.001). During a mean follow-up of 17 ± 11 months from the last procedure, patients with PsAFonset had significantly higher AF, atrial tachycardia (AT), and AF/AT recurrence rates (p < 0.01)., Conclusions: Patients with PsAFonset represent a distinct subgroup defined by specific demographics, underlying diffuse biatrial substrate disease, and worse clinical outcome. The findings highlight the importance of defining criteria for early detection of atrial substrate disease., (Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)