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Background: Pulmonary vein isolation (PVI) has become the cornerstone treatment of atrial fibrillation (AF). While in cryoablation cell damage is caused by thermal effects, lately, pulsed field ablation (PFA) has been established as a novel non-thermal tissue-specific ablation modality for PVI. However, data comparing outcomes of patients undergoing either PFA or cryoballoon ablation (CBA) for primary PVI are sparse., Methods: Consecutive patients with AF undergoing PVI by either CBA or PFA were included in the analysis. The primary outcome was the time to AF/AT recurrence. For secondary outcomes, clinical and periprocedural parameters were compared., Results: In total, outcomes of 141 AF patients treated by PFA (94 patients) or CBA (47 patients) were compared. After 365 days, 70% of patients in the PFA group and 61% of patients in the CBA group were free from AF/AT (HR 1.35, 95% CI 0.60-3.00; p = 0.470). No deaths occurred. While symptoms alleviated in both groups, only after PFA, we observed significant improvement of left atrial volume index (PFA group baseline: 40 [31;62] ml/m 2 , PFA group follow-up: 35 [29;49] ml/m 2 ; p = 0.015), NT-pro BNP levels (PFA group baseline: 1106 ± 2479 pg/ml, PFA group follow-up: 1033 ± 1742 pg/ml; p = 0.048), and left ventricular ejection fraction (LVEF) (PFA group baseline: 55 [48;60] %, PFA group follow-up: 58 [54;63] %; p = 0.006). PVI by PFA was the only independent predictor of LVEF improvement., Conclusion: In our study, we show that CBA and PFA for PVI are of similar efficacy when it comes to AF recurrence. However, our findings suggest that PFA rather than CBA might induce left atrial reverse remodeling thereby contributing to left ventricular systolic function., (© 2024. The Author(s).)

Pulsed field ablation (PFA) is an emerging technology for the treatment of atrial fibrillation (AF), for which pre-clinical and early-stage clinical data are suggestive of some degree of preferentiality to myocardial tissue ablation without damage to adjacent structures. Here in the MANIFEST-17K study we assessed the safety of PFA by studying the post-approval use of this treatment modality. Of the 116 centers performing post-approval PFA with a pentaspline catheter, data were received from 106 centers (91.4% participation) regarding 17,642 patients undergoing PFA (mean age 64, 34.7% female, 57.8% paroxysmal AF and 35.2% persistent AF). No esophageal complications, pulmonary vein stenosis or persistent phrenic palsy was reported (transient palsy was reported in 0.06% of patients; 11 of 17,642). Major complications, reported for ~1% of patients (173 of 17,642), were pericardial tamponade (0.36%; 63 of 17,642) and vascular events (0.30%; 53 of 17,642). Stroke was rare (0.12%; 22 of 17,642) and death was even rarer (0.03%; 5 of 17,642). Unexpected complications of PFA were coronary arterial spasm in 0.14% of patients (25 of 17,642) and hemolysis-related acute renal failure necessitating hemodialysis in 0.03% of patients (5 of 17,642). Taken together, these data indicate that PFA demonstrates a favorable safety profile by avoiding much of the collateral damage seen with conventional thermal ablation. PFA has the potential to be transformative for the management of patients with AF., (© 2024. The Author(s).)

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.)

Aims: Recent trial data demonstrate beneficial effects of active rhythm management in patients with atrial fibrillation (AF) and support the concept that a low arrhythmia burden is associated with a low risk of AF-related complications. The aim of this document is to summarize the key outcomes of the 9th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA)., Methods and Results: Eighty-three international experts met in Münster for 2 days in September 2023. Key findings are as follows: (i) Active rhythm management should be part of the default initial treatment for all suitable patients with AF. (ii) Patients with device-detected AF have a low burden of AF and a low risk of stroke. Anticoagulation prevents some strokes and also increases major but non-lethal bleeding. (iii) More research is needed to improve stroke risk prediction in patients with AF, especially in those with a low AF burden. Biomolecules, genetics, and imaging can support this. (iv) The presence of AF should trigger systematic workup and comprehensive treatment of concomitant cardiovascular conditions. (v) Machine learning algorithms have been used to improve detection or likely development of AF. Cooperation between clinicians and data scientists is needed to leverage the potential of data science applications for patients with AF., Conclusions: Patients with AF and a low arrhythmia burden have a lower risk of stroke and other cardiovascular events than those with a high arrhythmia burden. Combining active rhythm control, anticoagulation, rate control, and therapy of concomitant cardiovascular conditions can improve the lives of patients with AF., Competing Interests: Conflict of interest The 9th AFNET/EHRA consensus conference was partially supported by the European Union MAESTRIA project (grant agreement 965286) to AFNET. The following participants and authors are employees of companies active in cardiovascular health as indicated in their affiliations: M.D.M., E.D., C.E., G.H., L.H.H., T.H., R.H.v.L., M.W., and H.W. P.K. was partially supported by the European Union AFFECT-AF (grant agreement 847770) and MAESTRIA (grant agreement 965286), German Center for Cardiovascular Research supported by the German Ministry of Education and Research (DZHK, grant numbers DZHK FKZ 81X2800182, 81Z0710116, and 81Z0710110), German Research Foundation (Ki 509167694), and Leducq Foundation. He receives research support for basic, translational, and clinical research projects from several drug and device companies active in AF and has received honoraria from several such companies in the past, but not in the last 3 years. He is listed as an inventor on two issued patents held by the University of Hamburg (Atrial Fibrillation Therapy WO 2015140571, Markers for Atrial Fibrillation WO 2016012783). J.G.A. was partially supported by the Canadian Arrhythmia Network and the Michael Smith Foundation for Health Research, Baylis Medical. He receives consulting fees/honoraria from Bayer, BMS/Pfizer Alliance, Servier, and Medtronic Inc. E.A. receives consulting fees/honoraria from Biosense Webster and Bayer. G.B. receives consulting fees/honoraria from Bayer, BMS, Boston Scientific, Daiichi Sankyo, Sanofi, and Janssen. A.J.C. receives consulting fees/honoraria from Bayer, Pfizer/BMS, Daiichi Sankyo, Menarini, Sanofi, Boston Scientific, Biosense Webster, Abbott, Acesion Pharma, Huya Bio, and Milestone. V.C. receives consulting fees/honoraria from Bayer, Boehringer Ingelheim, and Ever Pharma (paid to the institution of employment). W.D. receives consulting fees/honoraria from Reata and research grants from MicroPort, Boston Scientific, and Abbott. S.Z.D. receives consulting fees from BMS/Pfizer, Cortrium, and Acesion Pharma and speaker fees from MS/Pfizer and Bayer. He is listed as a medical advisor for Vital Beats. Dobromir D. receives consulting fees/honoraria from Elsevier, Springer Healthcare Ltd, and Daiichi Sankyo and research grants as follows: four NIH grants (partially) from Baylor College of Medicine, Houston; one NIH grant from UC Davis, one NIH grant from the University of Minnesota, and one EU-Project H2020. David D. receives consulting fees/honoraria from Abbott, Astra Zeneca, Biotronik, Boehringer Ingelheim, Boston Scientific, BMS/Pfizer, CVRx, Medtronic, MicroPort, and Zoll and research grants from Roche, CVRx, and Zoll. L.E. has received lecture fees from various companies in AF in the past but none related to the present work. L.F. receives consulting fees/honoraria from Roche (paid to the institution of employment). She is currently employed at the UKE and previously at the University of Birmingham. She was partially supported by the European Union AFFECT-EU (grant agreement 847770), MAESTRIA (grant agreement 965286), CATCH ME (grant agreement 633196), and the British Heart Foundation (AA/18/2/3218). D.F.-R. receives research grants from Abbott. He is listed as an inventor on two issued patents: EP3636147A1 (method for the identification of cardiac fibrillation drivers and/or the footprint of rotational activations) and PCT/EP2022/071364 (system and method of assessment of electromechanical remodelling). A.G. receives consulting fees/honoraria from Daiichi Sankyo, Bayer, BMS/Pfizer, Medtronic, Abbott, and Boston Scientific and was partially supported by the European Union MAESTRIA (grant agreement 965286). K.G.H. receives consulting fees/honoraria from Abbott, Alexion, Amarin, Astra Zeneca, Bayer Healthcare, Biotronik, Boehringer Ingelheim, Boston Scientific, BMS/Pfizer, Daiichi Sankyo, Edwards Lifesciences, Medtronic, Novaris, Portola, Premier Research, Sanofi, SUN Pharma, and W. L. Gore and Associates. J.S.H. receives speaking fees from BMS/Pfizer, Bayer, Servier, and Boston Scientific and consulting fees from Bayer and Boston Scientific. He receives research grants from BMS/Pfizer, Servier, Novartis, Boston Scientific, and Medtronic. H.H. receives lecture and consulting fees from Bayer, Biotronik, BMS/Pfizer, Daiichi Sankyo, Milestone Pharmaceuticals, Centrix India, C.T.I. Germany, ESC, Medscape, and Springer Healthcare Ltd. He receives research grants (paid to the institution of employment, University of Antwerp and/or University of Hasselt) from Abbott, Bayer, Biosense Webster, Boston Scientific, Daiichi Sankyo, Fibricheck/Qompium, Medtronic, and BMS/Pfizer. Z.H. receives consulting fees/honoraria from Boehringer Ingelheim, BMS/Pfizer, and Roche Diagnostics. He was partially supported by The Swedish Society for Medical Research (S17-0133), Hjärt-Lungfonden (The Swedish Heart-Lung Foundation, 20200722), and the institution he is currently employed at (Uppsala University Hospital). L.H.-M. receives research grants from the Spanish Ministry of Science and Innovation (PID2020-116927RB-C21) and Fondo Europeo de Desarrollo Regional (FEDER). D.K. receives consulting fees/honoraria from Bayer, Amomed, and Protherics Medicines Development. He receives research grants from the National Institute for Health Research (NIHR CDF-2015-08-074 RAE-AF; NIHR130280 DaRe2THINK; NIHR13274 D2T-NeuroVascular; and NIHR203326 Biomedical Research Centre), the British Heart Foundation (PG/17/55/33087, AA/182/3218, and FS/CDRF/21/21032), the EU/EFPIA Innovative Medicines Initiative (BigData@Heart 116074), EU Horizon and UKRI (HYPERMARKER 101095480) UK National Health Service—Data for R&D-Subnational Secure Data Environment programme, UK Department for Business, Energy Industrial Strategy Regulators Pioneer Fund, the Cook & Wolstenholme Charitable Trust, and the European Society of Cardiology supported by educational grants from Boehringer Ingelheim, BMS/Pfizer, Alliance, Bayer, Daiichi Sankyo, Boston Scientific, the NIHR/University of Oxford Biomedical Research Centre, and the British Hear Foundation, the University of Birmingham Accelerator Award (STEEER-AF). J.L.M. receives consulting fees/honoraria from Biotronik, Medtronic, MicroPort, and Milestone Pharmaceuticals. A.M. receives consulting fees/honoraria from Medtronic, Biosense Webster, and Boston Scientific and lecture fees from Medtronic, Boston Scientific, Biosense Webster, BMS, and Bayer. L.M. receives consulting fees/honoraria from Abbott, Medtronic, Boston Scientific, and Johnson & Johnson. G.A.N. receives lecture fees from AliveCor, consultant fees from Biosense Webster, and research grants from Abbott and Biosense Webster. H.P. receives consulting fees/honoraria from Abbott, Boston Scientific, Biosense Webster, Medtronic, Daiichi Sankyo, Bayer, and Pfizer. P.S. receives consulting fees/honoraria from Medtronic, Boston Scientific, Abbott, CathRx, and PaceMate (paid to the institution of employment). He is currently employed at the University of Adelaide, which receives research grants from Medtronic, Boston Scientific, and Becton-Dickenson. R.B.S. receives consulting fees/honoraria from BMS/Pfizer. She was partially supported by the European Union Horizon 2020 research and innovation programme (grant agreement 648131 and 847770), German Center for Cardiovascular Research supported by the German Ministry of Education and Research (DZHK, grant numbers 81Z1710103 and 81Z0710114), German Ministry of Research and Education (BMBF 01ZX1408A), ERACoSysMed3 (031L0239), Wolfgang Seefried project funding German Heart Foundation. U.S. receives consulting fees/honoraria from University Svizzerra Italiana, Stanford, and Johnson & Johnson and research grants from the European Union, Dutch Heart Foundation, Roche, and EP Solution. He is a shareholder of YourRhythmics B.V. T.T. receives consulting fees/honoraria from Boston Scientific and Medtronic. I.C.v.G. receives consulting fees/honoraria from Bayer (paid to the institution of employment). She is currently employed at the University of Groningen. K.V. receives consulting fees/honoraria from Abbott, Philips, Medtronic, Biosense Webster, and Boston Scientific and research grants from Medtronic and Biosense Webster. R.W. receives consulting fees/honoraria from Boehringer Ingelheim, BMS/Pfizer, Daiichi Sankyo, Boston Scientific, Biotronik, Abiomed, and Zoll and a research grant from Boston Scientific, BMS/Pfizer, and Abiomed. S.W. receives consulting fees/honoraria from Boehringer Ingelheim, Boston Scientific, Abbott, and Bayer Vital and a research grant from Boston Scientific. All remaining authors (G.B., J.C.N., T.D.P., N.D., M.F., E.G., S.H., S.K., D.L., K.M.-R., M.O., A.S.P., U.R., M.R., D.S., C.S., G.S., D.S., S.T., R.H.v.L., and S.Z.) have declared no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Importance: Previous studies evaluating the association of patient sex with clinical outcomes using conventional thermal ablative modalities for atrial fibrillation (AF) such as radiofrequency or cryoablation are controversial due to mixed results. Pulsed field ablation (PFA) is a novel AF ablation energy modality that has demonstrated preferential myocardial tissue ablation with a unique safety profile., Objective: To compare sex differences in patients undergoing PFA for AF in the Multinational Survey on the Methods, Efficacy, and Safety on the Postapproval Clinical Use of Pulsed Field Ablation (MANIFEST-PF) registry., Design, Setting, and Participants: This was a retrospective cohort study of MANIFEST-PF registry data, which included consecutive patients undergoing postregulatory approval treatment with PFA to treat AF between March 2021 and May 2022 with a median follow-up of 1 year. MANIFEST-PF is a multinational, retrospectively analyzed, prospectively enrolled patient-level registry including 24 European centers. The study included all consecutive registry patients (age ≥18 years) who underwent first-ever PFA for paroxysmal or persistent AF., Exposure: PFA was performed on patients with AF. All patients underwent pulmonary vein isolation and additional ablation, which was performed at the discretion of the operator., Main Outcomes and Measures: The primary effectiveness outcome was freedom from clinically documented atrial arrhythmia for 30 seconds or longer after a 3-month blanking period. The primary safety outcome was the composite of acute (<7 days postprocedure) and chronic (>7 days) major adverse events (MAEs)., Results: Of 1568 patients (mean [SD] age, 64.5 [11.5] years; 1015 male [64.7%]) with AF who underwent PFA, female patients, as compared with male patients, were older (mean [SD] age, 68 [10] years vs 62 [12] years; P < .001), had more paroxysmal AF (70.2% [388 of 553] vs 62.4% [633 of 1015]; P = .002) but had fewer comorbidities such as coronary disease (9% [38 of 553] vs 15.9% [129 of 1015]; P < .001), heart failure (10.5% [58 of 553] vs 16.6% [168 of 1015]; P = .001), and sleep apnea (4.7% [18 of 553] vs 11.7% [84 of 1015]; P < .001). Pulmonary vein isolation was performed in 99.8% of female (552 of 553) and 98.9% of male (1004 of 1015; P = .90) patients. Additional ablation was performed in 22.4% of female (124 of 553) and 23.1% of male (235 of 1015; P = .79) patients. The 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was similar in male and female patients (79.0%; 95% CI, 76.3%-81.5% vs 76.3%; 95% CI, 72.5%-79.8%; P = .28). There was also no significant difference in acute major AEs between groups (male, 1.5% [16 of 1015] vs female, 2.5% [14 of 553]; P = .19)., Conclusion and Relevance: Results of this cohort study suggest that after PFA for AF, there were no significant sex differences in clinical effectiveness or safety events.

Background: Atrial cardiomyopathy (atCM) is an emerging prognostic factor in cardiovascular disease. Fibrotic remodeling, cardiomyocyte hypertrophy, and capillary density are hallmarks of atCM. The contribution of etiological factors and atrial fibrillation (AF) to the development of differential atCM phenotypes has not been quantified. This study aimed to evaluate the association between histological features of atCM and the clinical phenotype., Methods and Results: We examined left atrial (LA, n=95) and right atrial (RA, n=76) appendages from a European cohort of patients undergoing cardiac surgery. Quantification of histological atCM features was performed following wheat germ agglutinin/CD31/vimentin staining. The contributions of AF, heart failure, sex, and age to histological characteristics were determined with multiple linear regression models. Persistent AF was associated with increased endomysial fibrosis (LA: +1.13±0.47 μm, P =0.038; RA: +0.94±0.38 μm, P =0.041), whereas total extracellular matrix content was not. Men had larger cardiomyocytes (LA: +1.92±0.72 μm, P <0.001), while women had more endomysial fibrosis (LA: +0.99±0.56 μm, P =0.003). Patients with heart failure showed more endomysial fibrosis (LA: +1.85±0.48 μm, P <0.001) and extracellular matrix content (LA: +3.07±1.29%, P =0.016), and a higher capillary density (LA: +0.13±0.06, P =0.007) and size (LA: +0.46±0.22 μm, P =0.044). Fuzzy k-means clustering of histological features identified 2 subtypes of atCM: 1 characterized by enhanced endomysial fibrosis (LA: +3.17 μm, P <0.001; RA: +2.86 μm, P <0.001), extracellular matrix content (LA: +3.53%, P <0.001; RA: +6.40%, P <0.001) and fibroblast density (LA: +4.38%, P <0.001), and 1 characterized by cardiomyocyte hypertrophy (LA: +1.16 μm, P =0.008; RA: +2.58 μm, P <0.001). Patients with fibrotic atCM were more frequently female (LA: odds ratio [OR], 1.33, P =0.002; RA: OR, 1.54, P =0.004), with persistent AF (LA: OR, 1.22, P =0.036) or heart failure (LA: OR, 1.62, P <0.001). Hypertrophic features were more common in men (LA: OR=1.33, P =0.002; RA: OR, 1.54, P =0.004)., Conclusions: Fibrotic atCM is associated with female sex, persistent AF, and heart failure, while hypertrophic features are more common in men.

Background: Although atrial inflammation has been implicated in the pathophysiology of atrial fibrillation (AF), the identification of atrial inflammation remains challenging. We aimed to establish a positron emission tomography/computed tomography (PET/CT) protocol with 18 Fluor-labeled fluorodeoxyglucose ( 18 F-FDG) for the detection of atrial hypermetabolism as surrogate for inflammation in AF., Methods: We included n = 75 AF and n = 75 non-AF patients undergoing three common PET/CT protocols (n = 25 per group) optimized for the detection of (a) inflammation and (b) malignancy in predefined fasting protocols, and (c) cardiac viability allowing for maximized glucose uptake. 18 F-FDG-uptake was analyzed in predefined loci., Results: Differences of visual atrial uptake in AF vs non-AF patients were observed in fasting (inflammation [13/25 vs 0/25] and malignancy [10/25 vs 0/25]) protocols while viability protocols showed non-specific uptake in both the groups. In the inflammation protocol, AF patients showed higher uptake in the right atrium [(SUVmax: 2.5 ± .7 vs 2.0 ± .7, P = .01), atrial appendage (SUVmax: 2.4 ± .7 vs 2.0 ± .6, P = .03), and epicardial adipose tissue (SUVmax: 1.4 ± .5 vs 1.1 ± .4, P = .04)]. Malignancy and viability protocols failed to differentiate between AF and non-AF., Conclusion: Glucose uptake suppression protocols appear suitable in detecting differential atrial 18 F-FDG uptake between AF and non-AF patients. Imaging-based assessment of inflammation might help to stratify AF patients offering individualized therapeutic approaches., (© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.)

Background: Pulsed field ablation is a novel nonthermal cardiac ablation modality using ultra-rapid electrical pulses to cause cell death by a mechanism of irreversible electroporation. Unlike the traditional ablation energy sources, pulsed field ablation has demonstrated significant preferentiality to myocardial tissue ablation, and thus avoids certain thermally mediated complications. However, its safety and effectiveness remain unknown in usual clinical care., Methods: MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a retrospective, multinational, patient-level registry wherein patients at each center were prospectively included in their respective center registries. The registry included all patients undergoing postapproval treatment with a multielectrode 5-spline pulsed field ablation catheter to treat atrial fibrillation (AF) between March 1, 2021, and May 30, 2022. The primary effectiveness outcome was freedom from clinical documented atrial arrhythmia (AF/atrial flutter/atrial tachycardia) of ≥30 seconds on the basis of electrocardiographic data after a 3-month blanking period (on or off antiarrhythmic drugs). Safety outcomes included the composite of acute (<7 days postprocedure) and latent (>7 days) major adverse events., Results: At 24 European centers (77 operators) pulsed field ablation was performed in 1568 patients with AF: age 64.5±11.5 years, female 35%, paroxysmal/persistent AF 65%/32%, CHA 2 DS 2 -VASc 2.2±1.6, median left ventricular ejection fraction 60%, and left atrial diameter 42 mm. Pulmonary vein isolation was achieved in 99.2% of patients. After a median (interquartile range) follow-up of 367 (289-421) days, the 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was 78.1% (95% CI, 76.0%-80.0%); clinical effectiveness was more common in patients with paroxysmal AF versus persistent AF (81.6% versus 71.5%; P =0.001). Acute major adverse events occurred in 1.9% of patients., Conclusions: In this large observational registry of the postapproval clinical use of pulsed field technology to treat AF, catheter ablation using pulsed field energy was clinically effective in 78% of patients with AF., Competing Interests: Disclosures Dr Reddy reports receiving consulting fees (and equity—now divested) from Farapulse Inc. and is a consultant for Boston Scientific Inc; unrelated to this manuscript, Dr Reddy also serves 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, LuxMed, Medlumics, Middlepeak, Neutrace, Nuvera-Biosense Webster, Oracle Health, Restore Medical, Sirona Medical, SoundCath, Valcare; unrelated to this work, has served as a consultant for AtriAN, Biosense-Webster, BioTel Heart, Biotronik, Cairdac, Cardiofocus, Cardionomic, CoreMap, Fire1, Gore & Associates, Impulse Dynamics, Medtronic, Novartis, Philips, Pulse Biosciences; and has equity in Manual Surgical Sciences, Newpace, Nyra Medical, Surecor, and Vizaramed. Dr Schmidt reports receiving speaker’s fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. Dr Reichlin reports 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. Support for his institution’s fellowship programme from Abbott/SJM, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. Dr Roten reports receiving speaker honoraria from Abbott/SJM, consulting honoraria from Medtronic, and research funding to the institution from Medtronic. Dr Neven reports speaker’s fees from Farapulse, Inc. Dr Metzner reports research grant and fees from Farapulse. Dr Rollin reports receiving research grant from Farapulse. Dr Lemoine reports receiving research grant from Farapulse. Dr Hansen reports receiving speaker fees and grant support from Biosense Webster, and Medtronic. Dr Blaauw reports receiving research grants from Medtronic and Atricure and consulting fees from Abbott, Biosense Webster, Boston Scientific. Dr Sommer reports member of the advisory board for Abbott, Biosense Webster, Boston Scientific, and Medtronic. Dr Anic reports receiving consultant fees from Farapulse Inc., Boston Scientific Inc., Galaxy Medical Inc., Biosense Webster, and performs contracted research for Farapulse Inc., Boston Scientific Inc., Galaxy Medical Inc., and Biosense Webster. Dr Anselme reports receiving consulting fees from Boston Scientific, Medtronic, and Microport CRM. Dr Boveda reports receiving consulting fees from Medtronic, Boston Scientific, Microport, Zoll, and BMS. Dr Deneke reports receiving speaker honoraria from Galaxy Medical, Abbott, and Biotronik, being a consultant to Farapulse, and serving on a Clinical Events Committee for Boston Scientific. Dr Willems reports receiving grants and personal fees from Abbott, Boston Scientific, Medtronic, and personal fees from Boehringer Ingelheim, Brystol Myers Squibb, Bayer Vital, Accutus, Daiichi, and Farapulse Inc. Dr Gunawardene reports grants from Farapulse Inc. and Abbott. Dr Tilz reports receiving consulting fees from Boston Scientific, Abbott Medical, Biotronik, Biosense Webster and speaker honorarium from Boston Scientific, Abbott Medical, Biotronik, and Biosense Webster. Dr Heeger received travel grants and research grants by Boston Scientific, Lifetech, Biosense Webster, and Cardiofocus and Speaker´s Honoraria from Boston Scientific, Lifetech. Biosense Webster, Bayer, and Cardiofocus. He is a consultant of Medtronic, Lifetech, Boston Scientific, Biosense Webster, and Cardiofocus. Dr Scheer reports receiving an educational grant from Farapulse Inc. and is a consultant for Boston Scientific Inc. Dr Wakili reports receiving consultant fees and travel expenses from Boston Scientific and Biotronik; 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 reports receiving speaking 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 Sultan reports receiving lecture and consulting honoraria from Medtronic, Abbott, and Bayer. Dr Kautzner reports 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 reports receiving equity from Farapulse and consulting fees and grant from Boston Scientific. Dr Derval reports receiving consulting fees from Boston scientific. Dr Chun reports receiving speaker’s fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. Dr Neuzil reports receiving grants from the Ministry of Health, Czech Republic, DRO (NHH, 00023884). Dr Manninger reports receiving speaker fees from Bayer, Biosense Webster, Biotronik, Amomed, AOP Orphan, Boston Scientific, Daiichi Sankyo, BMS/Pfizer and research grants from Biosense Webster and Abbott. All remaining authors have declared no conflict of interest.

Despite marked progress in the management of atrial fibrillation (AF), detecting AF remains difficult and AF-related complications cause unacceptable morbidity and mortality even on optimal current therapy. This document summarizes the key outcomes of the 8th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA). Eighty-three international experts met in Hamburg for 2 days in October 2021. Results of the interdisciplinary, hybrid discussions in breakout groups and the plenary based on recently published and unpublished observations are summarized in this consensus paper to support improved care for patients with AF by guiding prevention, individualized management, and research strategies. The main outcomes are (i) new evidence supports a simple, scalable, and pragmatic population-based AF screening pathway; (ii) rhythm management is evolving from therapy aimed at improving symptoms to an integrated domain in the prevention of AF-related outcomes, especially in patients with recently diagnosed AF; (iii) improved characterization of atrial cardiomyopathy may help to identify patients in need for therapy; (iv) standardized assessment of cognitive function in patients with AF could lead to improvement in patient outcomes; and (v) artificial intelligence (AI) can support all of the above aims, but requires advanced interdisciplinary knowledge and collaboration as well as a better medico-legal framework. Implementation of new evidence-based approaches to AF screening and rhythm management can improve outcomes in patients with AF. Additional benefits are possible with further efforts to identify and target atrial cardiomyopathy and cognitive impairment, which can be facilitated by AI., Competing Interests: Conflict of interest: RBS has received lecture fees and advisory board fees from BMS/Pfizer outside this work and has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme under the grant agreement No 648131, from the European Union's Horizon 2020 research and innovation programme under the grant agreement No 847770 (AFFECT-EU) and German Center for Cardiovascular Research (DZHK e.V.) (8121710103); German Ministry of Research and Education (BMBF 01ZX1408A) and ERACoSysMed3 (031L0239).EAM is employee of Daiichi Sankyo Europe GmbH producing and marketing an oral anticoagulant (edoxaban). EA has received consulting / speaker fees for Biosense Webster. GB has received speaker's fees of small amount from Boston, Bayer, Daiichi, Boehringer. SB is consultant for Medtronic, Boston Scientific, Microport, and Zoll. JC has received consulting fees / honoraria fees from Acesion, Allergan, Alta Thera, Arca, lncarda, Menarini, Milestone, Sanofi, Bayer, Daiichi Sankyo, Pfizer, Abbott, Biosense Webster, Biotronik, Boston Scientific, Lilly, Medtronic, Johnson and Johnson. BC has received in kind contribution for research Support from iRhythm. WC has received advisory board fees for Roche Diagnostics AG. MDM is employee of Medtronic. SZB has received fees as member of Advisory Board in Bristol Myers Squibb-Pfizer. DD has received fees from Abbott, Astra Zenica, Bayer, Bosten Scientific, Bristol Myers Squibb-Pfizer, Medtonic, Zoll. LE has received lecture Honoria from Medtronic, Biotronik, Boston Scientific, Boehringer Ingelheim, Daiichy Sankyo, Bayer, MMS, Pfizer, Sanofi and received research grants from DFG and DGK. CE is employee of Preventicus GmbH. LF has received institutional research grants and non-financial support from European Union, DFG, British Heart Foundation, Medical Research Council (UK), NIHR, and several biomedical companies. The Institute of Cardiovascular Research, University of Birmingham, has received an Accelerator Award by the British Heart Foundation M/18/2/34218. LF is listed as inventor of two patents held by University of Birmingham (Atrial Fibrillation Therapy WO 2015140571, Markers for Atrial Fibrillation WO 2016012783). BF receiving fees from Bristol-Myers Squibb and Pfizer Alliance, Bayer, Daiichi Sankyo, Omron. (largely speaker fees and travel support for speaking at session or official satellites of large international/continental society meetings) and investigator-initiated research grants to the institution from Bristol-Myers and Squibb and Pfizer Alliance and Ownership / Employee of Nil. LG and AZ are employees of Roche Diagnostics International Ltd. AG has received funding from Daiichi Sankyo, Astra Zenica, Bayer, Bristol Myers Squibb-Pfizer, Viola, Medtonic, Berlin Charitè. JHS has received Advisory board fees in Medtronic and Speaker fee from Medtronic. KGH has received fees from Abbott, Alexion, AMARIN, AstraZeneca, Bayer, Biotronik, Boehringer Ingelheim, Bristol-Myers-Squibb, Daiichi Sankyo, Edwards Lifesciences, Medtronic, Pfizer, Premier Research, SUN Pharma and W. L. Gare & Associates and Research Grants from Bayer Vital, Sanofi-Aventis. JSH received fees from Boston Scientific, Servier, Bayer, Myokardia, Bristol-Myers-Squibb, Pfizer, and research grants from Medtronic, Boston Scientific, Bristol-Myers-Squibb, Abbott. HH has received lecture and consultancy fees from Abbott, Biotronik, Bristol-Myers-Squibb- Pfizer, Medscape, Daiichi Sankyo, Springer Healthcare Ltd and receive un conditional research grants through the Univerity of Antwerp and/or University of Hasselt from Abbott, Bayer, Biotronik, Biosense-Webster, Fibrickeck/Qompium, Medtronic, Bristol-Myers-Squibb- Pfizer, Boston Scientific, Daiichi Sankyo and Boehringer Ingelheim. RH has received speacker fees from BI, Bayer and Bristol-Myers-Squibb- Pfizer and AZ. TH is CEO of Preventicus GmbH. DK has received funding from Bayer, AtriCure, Protherics Medicines Development and Myokardia and Research grant from rants from the National Institute for Health Research (NIHR CDF-2015-08-074 RATE-AF; NIHR HTA-130280 DaRe2THINK; NIHR EME- 132974 D2T-NV), the British Heart Foundation (PG/17/55/33087 and AA/18/2/34218), EU/EFPIA IMI (BigData@Heart 116074),the European Society of Cardiology supported by educationalgrants from Boehringer Ingelheim/BMS-Pfizer Alliance/Bayer/Daiichi Sankyo/Boston Scientific, the NIHR/the University of Ox- ford Biomedical Research Centre, and British Heart Foundation/ the University of Birmingham Accelerator Award (STEEER-AF NCT04396418), Amomed Pharma, and IRCCS San Raffaele/Menarini (beta-blockers in Heart Failure Collaborative Group NCT0083244). MK is employee of Bristol-Myers and Squibb. CL has received fees from medtonic, Boston Scientific, Biotronik and Bristol-Myers and Squibb- Pfizer and research grants from Rennes Univerity, Metronik, Biotonik and Boston Scientific. DL has received research grant for EHRA-PATHS, NovoNordisk Young Investigator Award. MLL has received lecture fees from Bristol-Myers and Squibb and research grant from H2020 AFFECT-EU (grant No. 847770). SM has received research grant from Daiichi Sankyo (EPDAURUS IIT) and Bristol-Myers and Squibb (APPROACH ACS AF IIT). JLM has received Abbott, Boston Scientific, Biotronik, Boehringer Ingelheim, Sanofi, Microport and received research grants from Medtronic, Abbott, Microport, Biosense. RM is employee of Medtronic. LM is Stockholder for Galgomedical and Corify and receiving consuting fees from Abbott, Biosense-Webster, Bosten Scientific, Medtronik and receiving research grants from Abbott, Biosense-Webster, Bosten Scientific, Medtronik. LN has received consulting fees from Bristol-Myers and Squibb- Pfizer. GP is employee of Bayer AG. HP has received consulting fees from Abbott, Biosense-Webster, Bosten Scientific, Medtronik and receiving research grants from Abbott, Bayer, Biosense-Webster, Bosten Scientific, Medtronik, Bristol-Myers and Squibb- Pfizer. MR has received consulting fees for Medtonic, Arca BiopharmaInc, Roche and received research grants from Dutch Heart Foundation: RACE V, RED-CVD, CVON-AI, DECISION studies; grant from SJM/Abbott to institution: VIP-HF study; Grant for Medtronic to institution: Cryoballoon AF registry/biobank study. The other authors declare that there is no conflict of interest.LR has received research grants from Canadian Insititute of Health research and Byer Inc. U.S. received consultancy fees or honoraria from Università della Svizzera Italiana (USI, Switzerland), Roche Diagnostics (Switzerland), EP Solutions Inc. (Switzerland), Johnson & Johnson Medical Limited, (United Kingdom), Bayer Healthcare (Germany). U.S. is co-founder and shareholder of YourRhythmics BV, a spin-off company of the University Maastricht and Research grant from the Dutch Heart Foundation (CVON RACE V, CVON2014–09) European Union's Horizon 2020 Research and Innovation Program granted to MS under the Marie Sklodowska-Curie grant agreement #813716 (TRAIN-HEART Innovative Training Network), and various other programs of the European Union granted to US (ITN Network Personalize AF: Personalized Therapies for Atrial Fibrillation: a translational network – grant #860974; CATCH ME: Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly – grant #633196; MAESTRIA: Machine Learning Artificial Intelligence Early Detection Stroke Atrial Fibrillation – grant #965286; REPAIR: Restoring cardiac mechanical function by polymeric artificial muscular tissue – grant #952166). DS has received consultation fees from Biosense Webster, Abbott, Boston Scientific, Consultant with stock option: SentiAR, Arga Medtech. RS is employee of Daiichi Sankyo Europe GmbH. DS has received consultation fees from Boston Scientific, Abbott and Research grant from Biosense Webster. ES has received lecture fees from Bayer, Bristol-Myers and Squibb- Pfizer, Boehringer Ingelheim, Johnson & Johnson, Merck Sharp & Dohme and Sanofi. DT has received lecture fees from Bayer Vital, Bristol-Myers and Squibb- Pfizer, Daiichi Sankyo, Medtonic, Zoll CMS, Sanofi, St. Jude Medical and research grant from Daiichi Sankyo. MTH is employee/owner of American Foundation of women's Health /StopAfib.org and employee/owner of True Hills Inc.. BV is employee of Bayer AG. RW has received consultation fees from Boston Scientific, Biotronic, Pfizer, Daiichi Sankyo, Bayer, Adagio Medical and Research grant from Bristol-Myers and Squibb- Pfizer, Boston Scientific. CW has received consulation fees from Biotronik, Boston Scientific, Novartis and research grant from BMBF, AFNET, DZHK, Biotronik. MW is employee and shareholder of Sanofi. SW has received Consulting fees from Boston Scientific, Abbott, Bayer, Bristol-Myers and Squibb- Pfizer, Boehringer Ingelheim and research grant from Boston Scientific. HW is employee and stockholder of Pfizer Germany. MDZ has received advisory and speaker fee from Bristol-Myers and Squibb- Pfizer. PK reports grants and non-financial support from BMBF (German Ministry of Education and Research), grants from Sanofi and Abbott, grants and non-financial support from EHRA (European Heart Rhythm Association), and grants from German Heart Foundation and DZHK (German Center for Cardiovascular Research), during the conduct of the study, and grants from European Union, British Heart Foundation, Leducq Foundation, Medical Research Council (UK), and non-financial support from German Centre for Heart Research, outside the submitted work; in addition, P.K. has a patent Atrial Fibrillation Therapy WO 2015140571 issued to University of Birmingham and a patent Markers for Atrial Fibrillation WO 2016012783 issued to University of Birmingham., (© The Author(s) 2022. Published by Oxford University Press on behalf of European Society of Cardiology.)

Aims: Pulmonary vein isolation (PVI) either by balloon devices or radiofrequency forms the cornerstone of invasive atrial fibrillation (AF) treatment. Although equally effective cryoballoon (CB)-based PVI offers shorter procedure duration and a better safety profile. Beside the worldwide established Arctic Front Advance system, a novel CB device, POLARx, was recently introduced. This CB incorporates unique features, which may translate into improved efficacy and safety. However, multicentre assessment of periprocedural efficacy and safety is lacking up to date., Methods and Results: A total of 317 patients with paroxysmal or persistent AF were included and underwent POLARx CB-based PVI in 6 centres from Germany and Italy. Acute efficacy and safety were assessed in this prospective multicenter observational study. In 317 patients [mean age: 64 ± 12 years, 209 of 317 (66%) paroxysmal AF], a total of 1256 pulmonary veins (PVs) were identified and 1252 (99,7%) PVs were successfully isolated utilizing mainly the short tip POLARx CB (82%). The mean minimal CB temperature was -57.9 ± 7°C. Real-time PVI was registered in 72% of PVs. The rate of serious adverse events was 6.0% which was significantly reduced after a learning curve of 25 cases (9.3% vs. 3.0%, P = 0.018). The rate of recurrence-free survival after mean follow-up of 226 ± 115 days including a 90-day blanking period was 86.1%., Conclusion: In this large multicentre assessment, the novel POLARx CB shows a promising efficacy and safety profile after a short learning curve., Competing Interests: Conflict of interest: C.-H.H. received travel grants and research grants by Boston Scientific, Biosense Webster and Cardiofocus and Speaker’s Honoraria from Boston Scientific, Biosense Webster, Bayer and Cardiofocus. He is a consultant of Medtronic, Boston Scientific, Biosense Webster and Cardiofocus. R.R.T. is a consultant of Boston Scientific, Biotronik and Biosense Webster and received Speaker’s Honoraria from Biosense Webster, Medtronic, Boston Scientific and Abbot Medical. K.-H.K. reports grants and personal fees from Abbott Vascular, Medtronic, Biosense Webster outside submitted work. A.M. received speaker's honoraria and travel grants from Medtronic, Biosense Webster and Cardiofocus. A.P. received speaker’s honoraria and consulting fees from Medtronic, Biosense Webster, Daiichi-Sankyo, Bayer and is invited fellow of the Boston Scientific EP training programme. T.D. received speaker’s honoraria and consulting fees from Medtronic, Biosense Webster, Boerhringer-Ingelheim, Bayer, Daiichi-Sankyo. C.T. received Speaker’s and Proctor’s fees from Boston Scientific, Medtronic, Abbott and Biosense Webster. He serves in the Advisory Board of Medtronic, Boston Scientific. All remaining authors have declared no conflicts of interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Little is known about genome-wide changes in the atrial transcriptome as a cause or consequence of atrial fibrillation (AF), and the effect of its common and clinically relevant comorbidity-heart failure (HF)., Objective: The purpose of this study was to explore candidate disease processes for AF by investigating gene expression changes in atrial tissue samples from patients with and without AF, stratified by HF., Methods: RNA sequencing was performed in right and left atrial appendage tissue in 195 patients undergoing open heart surgery from centers participating in the CATCH-ME consortium (no history of AF, n = 91; paroxysmal AF, n = 53; persistent/permanent AF, n = 51). Analyses were stratified into patients with/without HF (n = 75/120) and adjusted for age, sex, atrial side, and a combination of clinical characteristics., Results: We identified 35 genes associated with persistent AF compared to patients without a history of AF, both in the presence or absence of HF (false discovery rate <0.05). These were mostly novel associations, including 13 long noncoding RNAs. Genes were involved in regulation of cardiomyocyte structure, conduction properties, fibrosis, inflammation, and endothelial dysfunction. Gene set enrichment analysis identified mainly inflammatory gene sets to be enriched in AF patients without HF, and gene sets involved in cellular respiration in AF patients with HF., Conclusion: Analysis of atrial gene expression profiles identified numerous novel genes associated with persistent AF, in the presence or absence of HF. Interestingly, no consistent transcriptional changes were associated with paroxysmal AF, suggesting that AF-induced changes in gene expression predominate other changes., (Crown Copyright © 2022. Published by Elsevier Inc. All rights reserved.)

Aims: Pulsed field ablation (PFA) is a novel atrial fibrillation (AF) ablation modality that has demonstrated preferential tissue ablation, including no oesophageal damage, in first-in-human clinical trials. In the MANIFEST-PF survey, we investigated the 'real world' performance of the only approved PFA catheter, including acute effectiveness and safety-in particular, rare oesophageal effects and other unforeseen PFA-related complications., Methods and Results: This retrospective survey included all 24 clinical centres using the pentaspline PFA catheter after regulatory approval. Institution-level data were obtained on patient characteristics, procedure parameters, acute efficacy, and adverse events. With an average of 73 patients treated per centre (range 7-291), full cohort included 1758 patients: mean age 61.6 years (range 19-92), female 34%, first-time ablation 94%, paroxysmal/persistent AF 58/35%. Most procedures employed deep sedation without intubation (82.1%), and 15.1% were discharged same day. Pulmonary vein isolation (PVI) was successful in 99.9% (range 98.9-100%). Procedure time was 65 min (38-215). There were no oesophageal complications or phrenic nerve injuries persisting past hospital discharge. Major complications (1.6%) were pericardial tamponade (0.97%) and stroke (0.4%); one stroke resulted in death (0.06%). Minor complications (3.9%) were primarily vascular (3.3%), but also included transient phrenic nerve paresis (0.46%), and TIA (0.11%). Rare complications included coronary artery spasm, haemoptysis, and dry cough persistent for 6 weeks (0.06% each)., Conclusion: In a large cohort of unselected patients, PFA was efficacious for PVI, and expressed a safety profile consistent with preferential tissue ablation. However, the frequency of 'generic' catheter complications (tamponade, stroke) underscores the need for improvement., Competing Interests: Conflict of interest: V.Y.R. reports receiving consulting fees and equity (stock) from Farapulse Inc. and is a consultant for Boston Scientific Inc.; he also has additional disclosures unrelated to this manuscript that are listed in the Supplementary material online. B.S. reports receiving speaker’s fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. T.R. reports 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. Support for his institution’s fellowship programme from Abbott/SJM, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. L.R. reports receiving speaker honoraria from Abbott/SJM and consulting honoraria from Medtronic. K.N. reports speaker’s Fees from Farapulse, Inc. A.M. reports research grant and fees from Farapulse. A.R. reports receiving research grant from Farapulse. J.H. reports receiving speaker fees and grant support from Biosense Webster and Medtronic. Y.B.: reports receiving Research grant from Medtronic and Atricure and consulting fees from Abbott, Biosense Webster, Boston Scientific. P.S. reports member of the advisory board for Abbott, Biosense Webster, Boston Scientific, and Medtronic. C.S. reports receiving modest honoraria from Medtronic. A.A. reports receiving consultant fees from Farapulse Inc., Boston Scientific Inc., Galaxy Medical Inc., Biosense Webster, and performs contracted research for Farapulse Inc., Boston Scientific Inc., Galaxy Medical Inc., Biosense Webster. F.A. reports receiving consulting fees from Boston Scientific, Medtronic and Microport CRM. S.B. reports receiving consulting fees for Medtronic, Boston Scientific, Microport, Zoll, and BMS. T.D. reports receiving speaker honoraria from Galaxy Medical, Abbott and Biotronik, being a consultant to Farapulse, and serving on a Clinical Events Committee for Boston Scientific. S.W. reports receiving grants and personal fees from Abbott, Boston Scientific, Medtronic, and personal fees from Boehringer Ingelheim, Brystol Myers Squibb, Bayer Vital, Accutus, Daiichi, Farapulse Inc. M.G. reports grant from Farapulse Inc. and Abbott. R.T. reports receiving consulting fees from Boston Scientific, Abbot Medical, Biotronik, and speakers honorarium from Boston Scientific, Abbot Medical, Biotronik, Biosense Webster. B.K. reports receiving Travel and Congress Sponsoring from Biotronik, Abbott, Impulse Dynamics, DGK AG EP, EHRA, Pfizer; she also received fellowship sponsoring from Johnson & Johnson, Boston Scientific and Lecture Honorary from Biotronik, Impulse Dynamics, C.T.I. GmbH, Doctrina Med. D.S. reports receiving an educational grant from Farapulse Inc., and is a consultant For Boston Scientific Inc. R.W. reports receiving consultant fees and travel expenses from Boston Scientific and Biotronik; 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. D.S. reports receiving speaking fees from Pfizer, Bayer, Abbott, Johnson & Johnson, and Medtronic; grant from Abbott, Johnson & Johnson, and Boston Scientific; and consulting fees from Boston Scientific and Johnson & Johnson. A.S. reports receiving lecture and consulting honoraria from Medtronic, Abbott, and Bayer. J.K. reports 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. P.J. reports receiving equity from Farapulse and consulting fees and grant from Boston Scientific. N.D. reports receiving consulting fees from Boston scientific. J.C. reports receiving speaker’s fees and research grants from Boston Scientific/Farapulse, Medtronic, Biosense Webster, and Abbott. P.N. reports receiving grant from the Ministry of Health, Czech Republic, DRO (NHH, 00023884). All the remaining authors have declared no conflict of interest., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: The study aimed to investigate the prevalence, phenotypic characteristics, and predictors of atrial fibrillation (AF) in patients presenting with cardiac amyloidosis (CA) of light-chain (AL) or transthyretin (ATTR) type., Methods and Results: Clinical, biochemical, and echocardiographic data of patients presenting with CA between 2005 and 2020 were retrospectively collected. CA staging was based on established biomarker systems. Binomial logistic regression was run to analyse the effects of clinical variables on the likelihood of AF. The study included 133 patients [53% AL, 41% wild-type (wt) ATTR-CA, & 6% hereditary ATTR-CA]. Mean age was 71 years, and 80% were male patients. AF was diagnosed in 64 (48%) patients (28% in AL-CA, 80% in wtATTR, 13% in hATTR, P < 0.001). Patients with AF were older (74 vs. 69 years, P < 0.001), more likely to have wtATTR-CA (67 vs. 16%, P < 0.001), exhibited more often New York Heart Association ≥ III symptoms (66 vs. 45%, P = 0.02) and carried a higher burden of comorbidities. AF patients had lower left ventricular ejection fraction (47 vs. 53%, P < 0.005), higher left atrial volume index (54 vs. 46 mL/m 2 , P = 0.007), higher pulmonary artery pressure (42 vs. 31 mmHg, P = 0.008), and worse tricuspid annular plane systolic excursion values (17 vs. 20 mm, P = 0.01). Mitral regurgitation ≥ Grade 2 was more frequent in AF (56 vs. 25%, P < 0.001). Higher ATTR-CA stage was associated with higher AF prevalence (47% vs. 74% vs. 94%, P < 0.001, for Stages I, II, & III, respectively). Higher AL-CA stage was associated with lower AF prevalence (0% vs. 40% vs. 31% vs. 18%, P < 0.001, for Stages I, II, IIIa, & IIIb, respectively). Three independent predictors for AF were identified in a multivariate logistic regression model with 81.5% classification accuracy: AL type [odds ratio (OR) 0.1, confidence interval (CI) 0.01-0.29, P = 0.001], estimated glomerular filtration rate (OR 0.9, CI 0.93-0.99, P = 0.03), and body mass index (OR 1.3, CI 1.07-1.66, P = 0.01). ATTR amyloidosis was associated with a 10-fold higher risk of AF. During 1 year follow-up, only one episode of ischaemic stroke was reported., Conclusions: Atrial fibrillation affects nearly half of all patients with CA. Patients presenting with AF have more severe symptoms and higher burden of comorbidities. ATTR type of amyloidosis is the strongest predictor of AF. Prospective screening for occult AF may be considered in ATTR-CA., (© 2022 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Purpose: 68  Ga-fibroblast-activation protein inhibitor (FAPI) positron emission tomography (PET) is a novel technique targeting FAP-alpha. This protein is expressed by activated fibroblasts which are the main contributors to tissue remodeling. The aim of this proof-of-concept study was to assess 68  Ga-FAPI uptake in the pulmonary vein (PV) region of the left atrium after pulmonary vein isolation (PVI) with cryoballoon ablation (CBA) and radiofrequency (RFA) as a surrogate for thermal damage., Methods: Twelve PVI patients (5 RFA, 7 CBA) underwent 68  Ga-FAPI-PET 20.5 ± 12.8 days after PVI. Five patients without atrial fibrillation or previous ablation served as controls. Standardized uptake values of localized tracer uptake were calculated., Results: Focal FAPI uptake around the PVs was observed in 10/12 (83.3%) PVI patients, no uptake was observed in 2 PVI patients and all controls. Patients after PVI had higher FAPI uptake in PVs compared to controls (SUV max : 4.3 ± 2.2 vs. 1.6 ± 0.2, p < 0.01; SUV peak : 2.9 ± 1.4 vs. 1.3 ± 0.2, p < 0.01). All CBA patients had an intense uptake, while in the RFA, group 2 (40%), 1 (20%), and 2 (40%) patients had an intense, moderate, and no uptake, respectively. We observed higher uptake values (SUV peak ) in CBA compared to RFA patients (4.4 ± 1.5 vs. 2.5 ± 0.8, p = 0.02)., Conclusion: We demonstrate in-vivo visualization of 68  Ga-FAPI uptake as a surrogate for fibroblast activation after PVI. CBA seems to cause more pronounced fibroblast activation following tissue injury than RFA. Future studies are warranted to assess if this modality can contribute to a better understanding of the mechanisms of AF recurrence after PVI by lesion creation and gap assessment., (© 2021. The Author(s).)

Atrial fibrillation (AF) is the most common arrhythmia and an important risk factor for the occurrence of cardiovascular events. According to current guidelines, rhythm-controlling therapy is recommended only for symptomatic AF. Even in symptomatic AF there is still only a class IIa-recommendation for catheter ablation as initial therapy in paroxysmal AF. Meanwhile, current studies have shown an advantage of the early rhythm control compared to a rate control, as well as a benefit of catheter ablation compared to antiarrhythmic drug (AAD) treatment. The gold standard of catheter ablation for AF therapy is pulmonary vein isolation, which has been mainly radiofrequency-based in the past. However, cryoablation as a first-line therapy of paroxysmal AF is increasingly gaining importance, as the latest studies showed shorter procedure times, lower reintervention rates and improved life quality after cryoablation. Nevertheless, using these standard techniques, the risk of adverse events is still given through collateral damage. The field high-power short duration ablation is currently topic of ongoing AF research, which describes a radiofrequency ablation with higher energy levels, given over shorter duration, with a consecutive lower recurrence rate as well as procedure time. The new ablation techniques also include the pulsed field ablation, which allows ablation through very fast delivery of electrical pulses and causes isolated damage to myocardial cells without collateral damage. This promising technique passed the efficiency and safety testing in preclinical studies. To validate this technique further randomized trials are needed., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Central retinal artery occlusion ((C)RAO) is known to be associated with stroke and/or atrial fibrillation (AF). Nevertheless, patients often present at the ophthalmologist initially and it is unknown how many of these receive an adequate cardiological/neurological work-up (CWU/NWU), including a 24 h-Holter-ECG., Hypothesis: Hypothesis of this study was that patients with (C)RAO do not undergo CWU on regular basis and that new-onset AF is more often detected in patients with CWU., Methods and Results: We performed a retrospective analysis of n = 292 consecutive patients who presented at an ophthalmology department with the diagnosis of (C)RAO during a 3-year period. After excluding patients with known AF, meeting exclusion criteria, inability to comply with the protocol, missed land phoneline, or death during follow-up a total of 174 patients were enrolled; mean follow-up was 20 ± 12 months. The CHA 2 DS 2 -VASc score of the cohort was 5.3 ± 1.4. Our analysis revealed that only 50.6% of patients received a CWU including a single Holter-ECG after the index-event. In 12.6% cases new-onset AF was diagnosed, while the rate was higher in patients with CWU compared to patients without CWU (18.2 vs. 7.0%; p = 0.26). Evaluation of oral anticoagulation (OAC) therapy showed that only 66% of patients with AF were treated according to guidelines., Conclusion: Only half of patients with (C)RAO underwent CWU. Despite minimal monitoring, rate of new diagnosed AF was high. Our results confirm that (C)RAO identifies a high-risk population for AF. These results illustrate the importance to implement standardized CWU in (C)RAO patients presenting at the ophthalmologist., (© 2021 The Authors. Clinical Cardiology published by Wiley Periodicals LLC.)

Objectives: Magnetic resonance angiography (MRA) has been established as an important imaging method in cardiac ablation procedures. In pulmonary vein (PV) isolation procedures, MRA has the potential to minimize the risk of severe complications, such as atrio-esophageal fistula, by providing detailed information on esophageal position relatively to cardiac structures. However, traditional non-gated, first-pass (FP) MRA approaches have several limitations, such as long breath-holds, non-uniform signal intensity throughout the left atrium (LA), and poor esophageal visualization. The aim of this observational study was to validate a respiratory-navigated, ECG-gated (EC), saturation recovery-prepared MRA technique for simultaneous imaging of LA, LA appendage, PVs, esophagus, and adjacent anatomical structures., Methods: Before PVI, 106 consecutive patients with a history of AF underwent either conventional FP-MRA ( n = 53 patients) or our new EC-MRA ( n = 53 patients). Five quality scores (QS) of LA and esophagus visibility were assessed by two experienced readers. The non-parametric Mann-Whitney U-test was used to compare QS between FP-MRA and EC-MRA groups, and linear regression was applied to assess clinical contributors to image quality., Results: EC-MRA demonstrated significantly better image quality than FP-MRA in every quality category. Esophageal visibility using the new MRA technique was markedly better than with the conventional FP-MRA technique (median 3.5 [IQR 1] vs median 1.0, p < 0.001). In contrast to FP-MRA, overall image quality of EC-MRA was not influenced by heart rate., Conclusion: Our ECG-gated, respiratory-navigated, saturation recovery-prepared MRA technique provides significantly better image quality and esophageal visibility than the established non-gated, breath-holding FP-MRA. Image quality of EC-MRA technique has the additional advantage of being unaffected by heart rate., Advances in Knowledge: Detailed information of cardiac anatomy has the potential to minimize the risk of severe complications and improve success rates in invasive electrophysiological studies. Our novel ECG-gated, respiratory-navigated, saturation recovery-prepared MRA technique provides significantly better image quality of LA and esophageal structures than the traditional first-pass algorithm. This new MRA technique is robust to arrhythmia (tachycardic, irregular heart rates) frequently observed in AF patients.

Aims: The risk of developing atrial fibrillation (AF) and its complications continues to increase, despite good progress in preventing AF-related strokes., Methods and Results: This article summarizes the outcomes of the 7th Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA) held in Lisbon in March 2019. Sixty-five international AF specialists met to present new data and find consensus on pressing issues in AF prevention, management and future research to improve care for patients with AF and prevent AF-related complications. This article is the main outcome of an interactive, iterative discussion between breakout specialist groups and the meeting plenary. AF patients have dynamic risk profiles requiring repeated assessment and risk-based therapy stratification to optimize quality of care. Interrogation of deeply phenotyped datasets with outcomes will lead to a better understanding of the cardiac and systemic effects of AF, interacting with comorbidities and predisposing factors, enabling stratified therapy. New proposals include an algorithm for the acute management of patients with AF and heart failure, a call for a refined, data-driven assessment of stroke risk, suggestions for anticoagulation use in special populations, and a call for rhythm control therapy selection based on risk of AF recurrence., Conclusion: The remaining morbidity and mortality in patients with AF needs better characterization. Likely drivers of the remaining AF-related problems are AF burden, potentially treatable by rhythm control therapy, and concomitant conditions, potentially treatable by treating these conditions. Identifying the drivers of AF-related complications holds promise for stratified therapy., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Premature atrial complexes (PACs) are a common finding in patients with structural heart disease, as well as in healthy subjects. In addition to the clinical spectrum ranging from asymptomatic patients to irritating palpitations, PACs are suggested to be associated with an increased risk of atrial fibrillation and stroke. Medical treatment leads to a significant reduction in PACs with clear symptom relief in a large proportion of patients, but is limited in cases of PACs that are refractory to antiarrhythmic drug (AAD) treatment. Furthermore, proarrhythmic effects of AAD or the patient's refusal of AAD treatment due to side effects need to be considered. Ablation of PACs is a good alternative to medical therapy with a comparable safety profile and at least comparable efficacy. In recent years, ultra-high-density (UHD) mapping with multiple improvements for successful ablation has been evolving. Before the introduction of UHD mapping, ablation strategies included activation mapping with single-tip catheters or conventional mapping aiming for the earliest activation of the PAC locally, with the earliest activation suspected to be the origin of the PAC and targeted by radiofrequency (RF) ablation. Using UHD mapping, a three-dimensional local activation map of the atrium can be acquired, identifying the point of earliest activation within the high-resolution map. PAC ablation has therefore developed into a true alternative for the treatment of symptomatic PACs.

Introduction: Left atrial flutter predominantly occurs after surgical or ablation procedures but this entity has also been recently reported in individuals without previous interventions. The use of high-density electroanatomical mapping-systems (HDM) has improved the understanding of underlying mechanisms beyond entrainment maneuvers and substrate analyses. We aimed to evaluate the mechanism of left atrial (LA) flutters in preablated vs ablation-naïve individuals and sought to assess the efficacy of empiric ablations sets in these groups., Methods and Results: We included 55 patients admitted for ablation of LA flutter between July 2017 and August 2019. On the basis of HDM analyses the arrhythmia mechanism was determined with consecutive ablation targeting the suspected critical isthmus. Mean age was 69.8 ± 10.7 years, with 26 of 55 (47.3%) male patients. Thirty-nine (71%) patients had previously undergone LA ablation. Arrhythmia mechanisms differed between preablated and ablation-naïve patients as anatomical structure-related LA flutters (perimitral, roof-dependent, within-pulmonary veins) were more frequent in the preablated cohort compared to ablation-naïve individuals (74.4% vs 43.8%; P = .03). In ablation-naïve patients, most flutters (9 of 16, 56.3%) were related to low-voltage areas at the anterior/posterior wall. Acute termination rates were high (>90%) in both groups. Empirical mitral isthmus or roof lines showed a potential higher success rate in preablated patients., Conclusion: We identified different mechanisms of LA flutters in preablated vs ablation-naïve patients. In ablation-naïve patients, most tachycardias involved low-voltage areas rather than anatomical structures. Using HDM, acute success rates were high. Hypothetical linear ablations were less successful in ablation-naïve individuals, further highlighting the need to identify the specific individual tachycardia mechanism in these patients., (© 2020 Wiley Periodicals LLC.)

Atrial fibrillation (AF) is a major healthcare challenge contributing to high morbidity and mortality. Treatment options are still limited, mainly due to insufficient understanding of the underlying pathophysiology. Further research and the development of reliable animal models resembling the human disease phenotype is therefore necessary to develop novel, innovative and ideally causal therapies. Since ischaemic heart failure (IHF) is a major cause for AF in patients we investigated AF in the context of IHF in a close-to-human porcine ischaemia-reperfusion model. Myocardial infarction (AMI) was induced in propofol/fentanyl/midazolam-anaesthetized pigs by occluding the left anterior descending artery for 90 minutes to model ischaemia with reperfusion. After 30 days ejection fraction (EF) was significantly reduced and haemodynamic parameters (pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), left ventricular enddiastolic pressure (LVEDP)) were significantly elevated compared to age/weight matched control pigs without AMI, demonstrating an IHF phenotype. Electrophysiological properties (sinus node recovery time (SNRT), atrial/AV nodal refractory periods (AERP, AVERP)) did not differ between groups. Atrial burst pacing at 1200 bpm, however, revealed a significantly higher inducibility of atrial arrhythmia episodes including AF in IHF pigs (3/15 vs. 10/16, p = 0.029). Histological analysis showed pronounced left atrial and left ventricular fibrosis demonstrating a structural substrate underlying the increased arrhythmogenicity. Consequently, selective ventricular infarction via LAD occlusion causes haemodynamic alterations inducing structural atrial remodeling which results in increased atrial fibrosis as the arrhythmogenic atrial substrate in pigs with IHF., Competing Interests: The authors have declared that no competing interests exist.

Atrial fibrillation, the most common cardiac arrhythmia in the daily clinical routine, is a challenge in in-hospital and prehospital emergency medicine and is associated with increased morbidity and mortality if left untreated. Especially tachyarrhythmia, caused by atrial fibrillation, leads to various unspecified symptoms and in some cases to severely impaired circulation. Thus, an individualized therapeutic regimen is required. A fundamental distinction between rhythm control and rate control strategies must be made. In symptomatic but hemodynamically stable patients rate control is the method of choice. This applies in particular to patients with no pre-existing anticoagulation, especially if left atrial thrombi are not excluded. In hemodynamically unstable patients, considering the potential complications of sedation, electrical cardioversion is preferred. Pharmacological therapy of atrial fibrillation has to be divided into AV conduction modulating drugs-like short- or long-acting β‑blockers, calcium antagonists or cardiac glycosides-and the heterogeneous group of antiarrhythmic drugs aiming for rhythm control. Pulmonary vein ablation is the current long-term treatment of choice for symptomatic drug-refractory atrial fibrillation.

Background: Atrial fibrillation (AF) is the most common clinical arrhythmia and one of the major causes of stroke, heart failure, sudden death, and cardiovascular morbidity. Despite substantial advances in (interventional) rhythm control treatment during the last decade, anticoagulation for stroke prevention remains a major component of AF treatment., Hypothesis: There are important sex-specific differences in AF-related stroke, resulting from sex-specific mechanisms and therapeutic differences., Methods: This review summarizes available data on sex differences in risk assessment and prevention of stroke and highlights current knowledge gaps in AF-related stroke mechanisms, prevention and management that warrant further research., Results: Increased thrombotic risk in women is multifactorial, involving hormonal changes after menopause, structural, endocrine and lifestyle/social factors and their interactions. It is clear from randomized studies that women benefit from anticoagulant treatment and that their bleeding risk is similar to men. Women should therefore receive equivalent treatment to men, based on the validated criteria for anticoagulation therapy. However, women are not represented equally in the large randomized studies and sex-related information in many fields is lacking., Conclusions: Female sex is an established risk factor for stroke in AF patients. The evidence for sex-specific differences in stroke risk assessment and stroke prevention is accumulating. However, the underlying biological mechanisms remain incompletely understood and further studies are required in order to decrease AF-related morbidity and mortality., (© 2019 The Authors. Clinical Cardiology published by Wiley Periodicals, Inc.)

Introduction: Periprocedural oral anticoagulation (OAC) strategies for atrial fibrillation (AF) ablation procedures are changing rapidly., Objective: To assess the management and course of periprocedural OAC for AF ablation procedures in experienced electrophysiology (EP) centers in Germany over the last 12 months., Methods: The data are based on an electronic questionnaire, which was sent to 35 experienced EP centers in September 2018 and then exactly 1 year later. Participants provided information on their periprocedural OAC management, the handling with dual therapy (OAC plus single antiplatelet therapy), the availability of specific antidotes, the transseptal puncture approach, and noteworthy complications., Results: Responses were received from all 35 centers and represent 10,010 AF ablation procedures annually. In 2018, the administration of vitamin K antagonist (VKA) was continued throughout the procedure at all centers (100%). In contrast, the majority of centers used minimally interrupted periprocedural non-vitamin K antagonist oral anticoagulants (NOAC) (54.3%), 13 centers (37.2%) completely interrupted NOAC, and only 3 centers (8.5%) continued NOAC throughout the procedure. At the 1-year follow-up survey, 32 centers were found to have continued their previous strategy of periprocedural OAC and 3 changed from a minimally interrupted to a continued NOAC strategy. Of note, 30 centers (85.7%) performed transseptal puncture fluoroscopically without additional cardiac imaging. In the setting of uninterrupted periprocedural OAC management, no relevant complications were noted., Conclusion: Our survey shows marked heterogeneous periprocedural OAC management at experienced EP centers in Germany. Whereas continuation of VKA has already been integrated into clinical practice, the majority of centers still use a minimally interrupted NOAC strategy., (© 2020 The Author(s) Published by S. Karger AG, Basel.)

Mechanistic understanding of atrial fibrillation (AF) pathophysiology and the complex bidirectional relationship with thromboembolic risk remains limited. Oral anticoagulation is a mainstay of AF management. An emerging concept is that anticoagulants may themselves have potential pleiotropic disease-modifying effects. We here review the available evidence for hemostasis-independent actions of the oral anticoagulants on electrical and structural remodeling, and the inflammatory component of the vulnerable substrate., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Pulmonary vein isolation (PVI) as interventional treatment for atrial fibrillation (AF) aims to eliminate arrhythmogenic triggers from the PVs. Improved signal detection facilitating a more robust electrical isolation might be associated with a better outcome. This retrospective cohort study compared PVI procedures using a novel high-density mapping system (HDM) with improved signal detection vs. age- and sex-matched PVIs using a conventional 3D mapping system (COM). Endpoints comprised freedom from AF and procedural parameters. In total, 108 patients (mean age 63.9 ± 11.2 years, 56.5% male, 50.9% paroxysmal AF) were included (n = 54 patients/group). Our analysis revealed that HDM was not superior regarding freedom from AF (mean follow-up of 494.7 ± 26.2 days), with one- and two-year AF recurrence rates of 38.9%/46.5% (HDM) and 38.9%/42.2% (COM), respectively. HDM was associated with reduction in fluoroscopy times (18.8 ± 10.6 vs. 29.8 ± 13.4 min; p < 0.01) and total radiation dose (866.0 ± 1003.3 vs. 1731.2 ± 1978.4 cGy; p < 0.01) compared to the COM group. HDM was equivalent but not superior to COM with respect to clinical outcome after PVI and resulted in reduced fluoroscopy time and radiation exposure. These results suggest that HDM-guided PVI is effective and safe for AF ablation. Potential benefits in comparison to conventional mapping systems, e.g. arrhythmia recurrence rates, have to be addressed in randomized trials.

During the past few decades, cardiovascular research has increasingly focused on systemic inflammatory mechanisms, particularly in the field of atherosclerosis but also in association with cardiac arrhythmogenesis. Objective inflammatory markers including C‑reactive protein and cytokines, also called "biomarkers," seem to serve as predictors of onset and prognosis of cardiac arrhythmias. This review gives an overview of potential mechanisms underlying inflammatory processes and arrhythmias, especially atrial fibrillation, which is the most common sustained arrhythmia in daily clinical routine. The association between inflammatory pathways and cardiac arrhythmia is highly complex and includes direct as well as indirect pathways. While past research into arrhythmia focused on fibrosis, altered action potential properties, and ischemia, novel concepts include coagulation and inflammation in cardiac tissue. The underlying mechanisms are altered electrophysiological properties, including ion channel disturbance, early and late afterdepolarizations, as well as enhanced fibrosis and structural remodeling in cardiomyopathies. These pathophysiological factors favor the occurrence of ectopic pacemakers as well as re-entry tachycardia. Further studies are essential to better understand the main inflammatory signal cascades and the exact proarrhythmic effect of interacting key mediators. This will facilitate the evaluation of future anti-inflammatory therapeutic approaches for arrhythmias, analogous to recent developments in atherosclerosis.

Introduction: Besides the traditional concept of atrial fibrillation (AF) perpetuating atrial structural remodeling, there is increasing evidence that atrial fibrosis might precede AF, highlighting the need for better characterization of the fibrotic substrate. We aimed to assess atrial fibrosis by use of late gadolinium enhancement magnetic resonance imaging (LGE-MRI) in non-AF individuals and to identify predisposing risk factors. A second aim was to establish a risk score for the prevalence of AF using atrial fibrosis in addition to established clinical variables., Methods and Results: Non-AF individuals without structural heart disease (n = 91) and matched AF controls (n = 91) underwent MRI for assessment of LGE. According to the established UTAH classification, atrial LGE ≥20% was considered extensive. Mean left atrial (LA) fibrosis in non-AF and AF individuals were 8.8 ± 6.5% and 12.5 ± 5.8%, respectively. Body mass index (BMI) >30 kg/m 2 and LA volume were predictors of atrial fibrosis. Diastolic function was not significantly different with respect to atrial fibrosis. A novel scoring system for the prevalence of AF (2 points for arterial hypertension and/or left ventricular ejection fraction <55%; 3 points for atrial fibrosis >6%) was derived demonstrating that patients in the intermediate/high-risk group had a significantly increased risk of AF., Conclusion: This study reports unexpectedly high atrial fibrosis in non-AF patients without apparent heart disease, highlighting the concept that structural fibrotic alterations may precede AF onset in a significant proportion of individuals. BMI as a predictor of atrial fibrosis suggests that lifestyle and drug intervention, that is, weight reduction, could positively influence fibrosis development. The derived risk score for AF prevalence provides the basis for prospective studies on AF incidence., (© 2019 Wiley Periodicals, Inc.)

In a prospective, randomized study we performed left atrial (LA) functional imaging and late gadolinium enhancement (LGE) in patients undergoing pulmonary vein isolation with ablation of the anterior mitral line to evaluate LA function and visibility of the anterior mitral line and to explore the relationship of these factors to short- and long-term procedural success. Functional imaging of the LA and LGE-visualization 15 min post i.v. administration of gadobutrol was performed on a 3 T MRI system before and after ablation. Patients were grouped in (a) subjects with sinus rhythm, and (b) subjects without sinus rhythm at the follow-up-MRI. Eight patients were excluded due to poor image quality. 37 patients were allotted to group a, 4 patients to group b. Group a showed a significant improvement in ejection fraction (22.3 ± 7.1% vs. 27.2 ± 5.5%; p < 0.001), end-systolic volume (111.6 ± 48.3 ml vs. 96.9 ± 37.2 ml; p = 0.002), stroke volume (30.2 ± 12.6 ml vs. 35.6 ± 12.6 ml; p = 0.003) and LGE (12.5% vs. 83.7%; p < 0.001). Group b showed no significant changes in functional parameters or LGE. Patients with successful therapy at 12 months showed significantly lower volumes in the baseline MRI. Scarring along the ablation pathways could be visualized with LGE. Patients with successful CA showed a significant improvement in LA cardiac parameters. Pre-ablation atrial volume seems to be a predictor for long-term success.

Arrhythmia-induced cardiomyopathy (AIC) is characterized by left ventricular systolic dysfunction for which the primary cause is arrhythmia. The hallmark of AIC is its reversibility once the arrhythmia is properly controlled. Any tachyarrhythmia can potentially cause AIC (often called "tachycardiomyopathy"), with atrial fibrillation (AF) being by far the most common in clinical practice. The pathophysiological mechanisms underlying AIC need further clarification, but the available evidence, principally from animal models, implicates metabolic dysfunction due to increased oxygen requirements, neurohormonal adaptive mechanisms, and cellular Ca 2+ mishandling as important contributors. Tachycardia is a common denominator of most cases of AIC, but other components specific to the patient and the arrhythmia have been implicated. The diagnosis of AIC requires the exclusion of a primary causative role of other conditions such as hypertension, primary cardiomyopathies, and valve disease, which may require specific pharmacological and invasive therapies. Catheter ablation is emerging as a safe and effective alternative to antiarrhythmic medication and has an established role in the management of AIC. Recent studies showing improved cardiac function and mortality rates in patients with heart failure and concomitant AF dramatically illustrate the often-unrecognized scope of AIC and the potential benefits of interventional therapy. Major AF trials do not otherwise focus specifically on AIC, and careful analysis of the literature is necessary to appreciate the clinical characteristics and therapeutic implications. This contemporary review summarizes the current understanding of pathophysiological mechanisms underlying AIC, discusses the clinical implications, and offers a general approach to management, with a particular focus on AF-induced cardiomyopathy., (Copyright © 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

There are major challenges ahead for clinicians treating patients with atrial fibrillation (AF). The population with AF is expected to expand considerably and yet, apart from anticoagulation, therapies used in AF have not been shown to consistently impact on mortality or reduce adverse cardiovascular events. New approaches to AF management, including the use of novel technologies and structured, integrated care, have the potential to enhance clinical phenotyping or result in better treatment selection and stratified therapy. Here, we report the outcomes of the 6th Consensus Conference of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA), held at the European Society of Cardiology Heart House in Sophia Antipolis, France, 17-19 January 2017. Sixty-two global specialists in AF and 13 industry partners met to develop innovative solutions based on new approaches to screening and diagnosis, enhancing integration of AF care, developing clinical pathways for treating complex patients, improving stroke prevention strategies, and better patient selection for heart rate and rhythm control. Ultimately, these approaches can lead to better outcomes for patients with AF.

Background: The relation between arrhythmias and stress is known. The aim of our current study was to elucidate whether plasma levels of previously described stress parameters are altered in highly symptomatic patients with atrial fibrillation (AF) per se and in patients undergoing ablation therapy by pulmonary vein isolation (PVI)., Methods: 96 patients with AF undergoing PVI were recruited. Plasma levels of Endothelin-1 (ET-1), MCP-1 and Chromogranin-A (CGA) were measured before and three months after ablation completed with clinical follow-up with respect to AF recurrence. Additionally, we examined 40 healthy age- and sex-matched volunteers as a reference., Results: Symptomatic AF patients showed increased levels of ET-1 compared to healthy controls (2.62pg/ml vs. 1.57pg/ml; p<0.01). Baseline levels of ET-1 were higher in patients presenting with AF after PVI (2.96pg/ml vs. 2.57pg/ml;p = 0.02). The temporal comparison revealed decreased ET-1 levels in patients without (2.57pg/ml vs. 2.33pg/ml; p<0.01) and unchanged ET-1 levels in patients with AF after PVI. Baseline MCP-1 was increased in AF patients vs. controls (268pg/ml vs. 227 pg/ml; p = 0.03). Both groups, with and without AF after PVI, showed an increase of MCP-1 compared to baseline (268pg/ml vs. 349pg/ml;p<0.01; 281pg/ml vs. 355pg/ml;p = 0.03). CGA was lower in AF patients compared to healthy controls (13.8ng/ml vs. 25.6ng/ml;p<0.01). Over time patients without AF after PVI showed an increase of CGA (14.2ng/ml vs. 20.7ng/ml;p<0.01). No change was observed in patients with AF after PVI., Conclusion: Our study demonstrated dysregulated levels of ET-1, MCP-1 and CGA in symptomatic AF patients. We could demonstrate an association between ET-1 to presence or absence of AF. Furthermore, we could show that a decrease of ET-1 as well as an increase of CGA after PVI, representing a trend towards control cohort levels, were both associated with restoration of sinus rhythm. These results provide new insights into the role of stress-related biomarkers in AF and AF treatment by ablation therapy.

Aims: Pulmonary vein isolation (PVI) is an established therapy for atrial fibrillation (AF). However, PVI remains a time-consuming procedure. A novel multipolar irrigated radiofrequency (RF) ablation catheter (nMARQ™) is aiming to improve PVI. We investigated the influence on procedural parameters and assessed clinical outcomes after PVI using this novel catheter., Methods and Results: Fifty-eight consecutive patients with paroxysmal AF were equally allocated (n = 29/group) to PVI treatment with (i) the novel multipolar ablation catheter (nMARQ™) and (ii) a standard single-tip ablation catheter (SAC). Study endpoints included procedure time, fluoroscopy time, radiation dose, RF time, number of energy applications, and clinical outcome defined as freedom from AF after a single procedure. Successful PVI was confirmed by a separate circular, multipolar mapping catheter in all patients treated with the nMARQ™. Pulmonary vein isolation was achieved in 100% in the SAC group. In the nMARQ™ group, PVI was suggested in all patients. However, confirmatory mapping revealed persistent pulmonary vein (PV) conduction in 19 out of 29 nMARQ™ patients. These patients underwent further ablation, which still failed to achieve PVI in 5 of the 29 nMARQ™ patients, mainly due to significant temperature rise in the oesophagus and device-related limitations reaching the right inferior PV. Mean fluoroscopy time (31 ± 12 vs. 23 ± 10 min, P < 0.05) and (132 ± 37 vs. 109 ± 30 min, P < 0.05) were longer in nMARQ™ vs. SAC patients. Radiofrequency time was shorter in nMARQ™ vs. SAC group (21 ± 9 vs. 35 ± 12 min, P < 0.001). Radiation dose and the number of energy applications did not differ between both groups. Clinical outcome analysis revealed no significant differences (nMARQ™: 72 vs. SAC: 72%) after a mean follow-up of 373 ± 278 days., Conclusion: The use of the nMARQ™ catheter is associated with important device-related limitations to achieve successful PVI. However, clinical outcomes were equivalent in nMARQ™- and SAC-treated patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia with a strong genetic component. Molecular pathways involving the homeodomain transcription factor Shox2 control the development and function of the cardiac conduction system in mouse and zebrafish. Here we report the analysis of human SHOX2 as a potential susceptibility gene for early-onset AF. To identify causal variants and define the underlying mechanisms, results from 378 patients with early-onset AF before the age of 60 years were analyzed and compared to 1870 controls or reference datasets. We identified two missense mutations (p.G81E, p.H283Q), that were predicted as damaging. Transactivation studies using SHOX2 targets and phenotypic rescue experiments in zebrafish demonstrated that the p.H283Q mutation severely affects SHOX2 pacemaker function. We also demonstrate an association between a 3'UTR variant c.*28T>C of SHOX2 and AF (p = 0.00515). Patients carrying this variant present significantly longer PR intervals. Mechanistically, this variant creates a functional binding site for hsa-miR-92b-5p. Circulating hsa-miR-92b-5p plasma levels were significantly altered in AF patients carrying the 3'UTR variant (p = 0.0095). Finally, we demonstrate significantly reduced SHOX2 expression levels in right atrial appendages of AF patients compared to patients with sinus rhythm. Together, these results suggest a genetic contribution of SHOX2 in early-onset AF.

MicroRNAs (miRNAs) are small non-coding RNAs, which are directly involved in the regulation of post-transcriptional gene expression. Their biological function represents a repression of protein expression of the targeted messenger-RNA(s). Expression of several miRNAs is somehow tissue-specific or cell-specific and their expression pattern can reflect an underlying pathophysiological condition. Beyond this biological function their role as potential biomarkers has been emerged in the past years. This was based on the fact that miRNAs can be detected in blood samples (serum or plasma) in a surprisingly stable form, by contrast to mRNAs. This fact made miRNAs interesting candidates for biomarkers providing information with respect to a potentially ongoing pathophysiological condition and could thereby have an impact on specific treatment strategies in patients. In this review we try to provide an overview of the potential role of miRNAs as a diagnostic tool in atrial fibrillation and heart failure patients taken different methodological aspects and distinct type of patients into account., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Despite remarkable advances in antiarrhythmic drugs, ablation procedures, and stroke-prevention strategies, atrial fibrillation (AF) remains an important cause of death and disability in middle-aged and elderly individuals. Unstructured management of patients with AF sharply contrasts with our detailed, although incomplete, knowledge of the mechanisms that cause AF and its complications. Altered calcium homeostasis, atrial fibrosis and ageing, ion-channel dysfunction, autonomic imbalance, fat-cell infiltration, and oxidative stress, in addition to a susceptible genetic background, contribute to the promotion, maintenance, and progression of AF. However, clinical management of patients with AF is currently guided by stroke risk parameters, AF pattern, and symptoms. In response to this apparent disconnect between the known pathophysiology of AF and clinical management, we propose a roadmap to develop a set of clinical markers that reflect the major causes of AF in patients. Thereby, the insights into the mechanisms causing AF will be transformed into a format that can underpin future personalized strategies to prevent and treat AF, ultimately informing better patient care.

Background: Pulmonary vein isolation (PVI) is an established procedure to treat atrial fibrillation (AF). New techniques are necessary to improve procedural parameters like shortening of procedure duration. Real-time contact force (CF) catheters are new tools aiming to improve PVI by optimizing electrode-tissue contact and generating more effective lesions. Objective of this study was to investigate the influence on procedural parameters and clinical outcome by using a CF catheter for PVI., Methods: PVI was performed on 67 consecutive patients using a CF catheter (n = 32) or a standard ablation catheter (SAC, n = 35). Study endpoints included number of energy applications, impedance drop, fluoroscopy time, and left atrial (LA) procedure time and freedom from AF after 6 and 12 months., Results: Procedural endpoint was reached in all patients with a similar clinical outcome (freedom from AF) in both groups 6 months (62.9 vs. 62.5%) and 12 months post PVI (59.4 vs. 62.9% in CF vs. SAC group, respectively). However, CF-guided ablation resulted in a greater fall of impedance (6.58 ± 0.33 vs. 9.09 ± 0.53 Ω, *** p < 0.001), lower number of energy applications (44.20 ± 3.67 vs. 34.06 ± 3.11, * p < 0.05), reduction of LA procedure time (95.52 ± 7.35 vs. 78.08 ± 7.23* min) and a significant reduction of fluoroscopy time (51.4 ± 3.3 vs. 33.0 ± 2.7*** min). In addition, a detailed analysis showed a significant correlation between quantitative impedance drop and amount of CF applied, suggesting more efficient lesion creation by CF-guided ablation., Conclusion: Use of CF catheters in PVI has a beneficial effect on procedural parameters, probably by improving efficacy of transmural lesion formation.

Introduction: Pericardial adipose tissue (PAT), a visceral fat depot surrounding the heart, serves as an endocrine active organ and is associated with inflammation. There is growing evidence that atrial fibrillation (AF) is linked with inflammation, which in turn can be a promoter of left atrial remodeling. The aim of this study was to evaluate a potential correlation of PAT to AF and left atrial structural remodeling represented by LA size., Methods: PAT was measured in 1,288 patients who underwent coronary artery calcium-scanning for coronary risk stratification. LA size was determined by two independent readers. Patients were subdivided into patients without AF, patients with paroxysmal and persistent AF., Results: PAT was independently correlated with AF, persistent AF, and LA size (all p values <0.001). No association could be observed between paroxysmal AF and PAT. These associations persisted after multivariate adjustment for AF risk factors such as age, hypertension, valvular disease, heart failure, and body mass index (AF: OR 1.52, 95 % CI 1.15-2.00, p = 0.003; persistent AF: OR 2.58, 95 % CI 1.69-3.99, p = 0.001; LA size: regression coefficient 0.15 with 95 % CI 0.10-0.20, p < 0.001)., Conclusion: PAT is associated with AF, in particular with persistent AF and LA size. These findings suggest that PAT could be an independent risk factor for the development of AF and for LA remodeling.

Background: Congestive heart failure (CHF) causes atrial fibrotic remodeling, a substrate for atrial fibrillation (AF) maintenance. MicroRNA29 (miR29) targets extracellular matrix proteins. In the present study, we examined miR29b changes in patients with AF and/or CHF and in a CHF-related AF animal model and assessed its potential role in controlling atrial fibrous tissue production., Methods and Results: Control dogs were compared with dogs subjected to ventricular tachypacing for 24 hours, 1 week, or 2 weeks to induce CHF. Atrial miR29b expression decreased within 24 hours in both whole atrial tissue and atrial fibroblasts (-87% and -92% versus control, respectively; p<0.001 for both) and remained decreased throughout the time course. Expression of miR29b extracellular matrix target genes collagen-1A1 (COL1A1), collagen-3A1 (COL3A1), and fibrillin increased significantly in CHF fibroblasts. Lentivirus-mediated miR29b knockdown in canine atrial fibroblasts (-68%; p<0.01) enhanced COL1A1, COL3A1, and fibrillin mRNA expression by 28% (p<0.01), 19% (p<0.05), and 20% (p<0.05), respectively, versus empty virus-infected fibroblasts and increased COL1A1 protein expression by 90% (p<0.05). In contrast, 3-fold overexpression of miR29b decreased COL1A1, COL3A1, and fibrillin mRNA by 65%, 62%, and 61% (all p<0.001), respectively, versus scrambled control and decreased COL1A1 protein by 60% (p<0.05). MiR29b plasma levels were decreased in patients with CHF or AF (by 53% and 54%, respectively; both p<0.001) and were further decreased in patients with both AF and CHF (by 84%; p<0.001). MiR29b expression was also reduced in the atria of chronic AF patients (by 54% versus sinus rhythm; p<0.05). Adenoassociated viral-mediated knockdown of miR29b in mice significantly increased atrial COL1A1 mRNA expression and cardiac tissue collagen content., Conclusions: MiR29 likely plays a role in atrial fibrotic remodeling and may have value as a biomarker and/or therapeutic target.

Atrial fibrillation is a highly prevalent arrhythmia and a major risk factor for stroke, heart failure and death. We conducted a genome-wide association study (GWAS) in individuals of European ancestry, including 6,707 with and 52,426 without atrial fibrillation. Six new atrial fibrillation susceptibility loci were identified and replicated in an additional sample of individuals of European ancestry, including 5,381 subjects with and 10,030 subjects without atrial fibrillation (P < 5 × 10(-8)). Four of the loci identified in Europeans were further replicated in silico in a GWAS of Japanese individuals, including 843 individuals with and 3,350 individuals without atrial fibrillation. The identified loci implicate candidate genes that encode transcription factors related to cardiopulmonary development, cardiac-expressed ion channels and cell signaling molecules.

Atrial fibrillation represents the most common form of clinical arrhythmia in daily routine. However, current therapeutic options are still limited and a better understanding of the underlying molecular mechanisms is expected to contribute to the development of new therapeutic strategies. The scientific field of microRNA research has received a lot of attention in recent years, especially regarding cardiovascular research. This article gives a brief overview of the most recent developments in microRNA research in the field of atrial fibrillation and atrial remodelling processes. Furthermore, the clinical perspective of microRNAs as new therapeutic targets and as potential biomarkers is discussed.

Rationale: Atrial fibrillation (AF) causes atrial-tachycardia remodeling (ATR), with enhanced constitutive acetylcholine-regulated K+ current (I(KAChC)) contributing to action potential duration shortening and AF promotion. The underlying mechanisms are unknown., Objective: To evaluate the role of protein-kinase C (PKC) isoforms in ATR-induced I(KAChC) activation., Methods and Results: Cells from ATR-dogs (400-bpm atrial pacing for 1 week) were compared to control dog cells. In vitro tachypaced (TP; 3 Hz) canine atrial cardiomyocytes were compared to parallel 1-Hz paced cells. I(KAChC) single-channel activity was assessed in cell-attached and cell-free (inside-out) patches. Protein expression was assessed by immunoblot. In vitro TP activated I(KAChC), mimicking effects of in vivo ATR. Discrepant effects of PKC activation and inhibition between control and ATR cells suggested isoform-selective effects and altered PKC isoform distribution. Conventional PKC isoforms (cPKC; including PKCα) inhibited, whereas novel isoforms (including PKCε) enhanced, acetylcholine-regulated K+ current (I(KACh)) in inside-out patches. TP and ATR downregulated PKCα (by 33% and 37%, respectively) and caused membrane translocation of PKCε, switching PKC predominance to the stimulatory novel isoform. TP increased [Ca2+]i at 2 hours by 30%, with return to baseline at 24 hours. Buffering [Ca2+]i during TP with the cell-permeable Ca2+ chelator BAPTA-AM (1 μmol/L) or inhibiting the Ca2+-dependent protease calpain with PD150606 (20 μmol/L) prevented PKCα downregulation and TP enhancement of I(KAChC). PKCε inhibition with a cell-permeable peptide inhibitor suppressed TP/ATR-induced I(KAChC) activation, whereas cPKC inhibition enhanced I(KAChC) activity in 1-Hz cells., Conclusions: PKC isoforms differentially modulate I(KACh), with conventional Ca(2+)-dependent isoforms inhibiting and novel isoforms enhancing activity. ATR causes a rate-dependent PKC isoform switch, with Ca2+/calpain-dependent downregulation of inhibitory PKCα and membrane translocation of stimulatory PKCε, enhancing I(KAChC). These findings provide novel insights into mechanisms underlying I(KAChC) dysregulation in AF.

Atrial fibrillation (AF) is an extremely common cardiac rhythm disorder that causes substantial morbidity and contributes to mortality. The mechanisms underlying AF are complex, involving both increased spontaneous ectopic firing of atrial cells and impulse reentry through atrial tissue. Over the past ten years, there has been enormous progress in understanding the underlying molecular pathobiology. This article reviews the basic mechanisms and molecular processes causing AF. We discuss the ways in which cardiac disease states, extracardiac factors, and abnormal genetic control lead to the arrhythmia. We conclude with a discussion of the potential therapeutic implications that might arise from an improved mechanistic understanding.

Background: Coronary artery disease predisposes to atrial fibrillation (AF), but the effects of chronic atrial ischemia/infarction on AF-related substrates are unknown., Methods and Results: Regional right atrial myocardial infarction (MI) was created in 40 dogs by ligating an artery that supplies the right atrial free wall and not the ventricles; 35 sham dogs with the same artery isolated but not ligated were controls. Dogs were observed 8 days after MI and subjected to open-chest study, in vitro optical mapping, and/or cell isolation for patch-clamp and Ca(2+) imaging on day 8. Holter ECGs showed more spontaneous atrial ectopy in MI dogs (eg, 662±281 on day 7 versus 34±25 ectopic complexes per day at baseline; 52±21 versus 1±1 atrial tachycardia episodes per day). Triggered activity was increased in MI border zone cells, which had faster decay of caffeine-evoked Ca(2+) transients and enhanced (by ≈73%) Na(+)-Ca(2+) exchange current. Spontaneous Ca(2+) sparks (confocal microscopy) occurred under β-adrenergic stimulation in more MI dog cells (66±9%) than in control cells (29±4%; P<0.01). Burst pacing induced long-lasting AF in MI dogs (1146±259 versus 30±14 seconds in shams). Increased border zone conduction heterogeneity was confirmed by both bipolar electrode mapping in vivo and optical mapping. Optical mapping demonstrated stable border zone reentry in all 9 MI preparations but in none of 6 shams. Border zone tissue showed increased fibrous tissue content., Conclusions: Chronic atrial ischemia/infarction creates substrates for both spontaneous ectopy (Ca(2+)-release events, increased Na(+)-Ca(2+) exchange current) and sustained reentry (conduction abnormalities that anchor reentry). Thus, chronic atrial infarction in dogs promotes both AF triggers and the substrate for AF maintenance. These results provide novel insights into potential AF mechanisms in patients with coronary artery disease.

Aims: Atrial fibrillation (AF)-induced contractile dysfunction contributes importantly to thrombo-embolic stroke, the most serious AF complication. Atrial cardiomyocytes have a constitutively active acetylcholine-regulated K(+)-current (I(KAChc)) that is enhanced by atrial tachycardia (AT). I(KAChc) contributes to action potential duration (APD) shortening in AT-remodelled atrial cardiomyocytes; APD regulates contractility by controlling Ca(2+)-loading and systolic Ca(2+)-release. This study investigated the potential role of I(KAChc) in AF-related contractile dysfunction., Methods and Results: Dogs were divided into two groups: (i) unpaced control (CTL); (ii) AT (400 bpm for at least 7 days). Tertiapin-Q (TQ), a selective I(KAChc) blocker, was used to define I(KAChc) contributions to contractility. Single-cell left atrial (LA) intracellular Ca(2+)-transients (CaTrs), cell-shortening (CS), and whole LA tissue tension-generation were measured. Atrial tachycardia increased I(KAChc). Whole LA contractility was decreased in AT (0.17 ± 0.05 g) compared with CTL (0.40 ± 0.09 g), with significant reversal (0.30 ± 0.06 g) after TQ administration. Ca(2+)-transient amplitude and CS in single-cell were decreased by AT compared with CTL (167 ± 14 vs. 88 ± 10 nM; 10.3 ± 1.3 vs. 1.7 ± 0.3 µm, respectively; P < 0.001). The AT-induced reductions in single-cell CaTr amplitude and CS were partly reversed by TQ administration (88 ± 10 vs. 112 ± 16 nM; P < 0.001; 1.7 ± 0.3 vs. 3.6 ± 0.7 µm; P < 0.01). We then measured CaTr and CS with carbachol and/or TQ to vary I(KACh) at various extracellular [Ca(2+)]. The CaTr-CS relationship was linear and AT results fell on the regression line, indicating that AT-remodelling effects on contractility are attributable to reduced CaTr., Conclusion: Up-regulated I(KAChc) contributes to AF-related contractile dysfunction and could be a novel target to prevent hypocontractility-related thrombo-embolic complications.

Background: Atrial fibrillation impairs atrial contractility, inducing atrial stunning that promotes thromboembolic stroke. Action potential (AP)-prolonging drugs are reported to normalize atrial hypocontractility caused by atrial tachycardia remodeling (ATR). Here, we addressed the role of AP duration (APD) changes in ATR-induced hypocontractility., Methods and Results: ATR (7-day tachypacing) decreased APD (perforated patch recording) by ≈50%, atrial contractility (echocardiography, cardiomyocyte video edge detection), and [Ca(2+)](i) transients. ATR AP waveforms suppressed [Ca(2+)](i) transients and cell shortening of control cardiomyocytes; whereas control AP waveforms improved [Ca(2+)](i) transients and cell shortening in ATR cells. However, ATR cardiomyocytes clamped with the same control AP waveform had ≈60% smaller [Ca(2+)](i) transients and cell shortening than control cells. We therefore sought additional mechanisms of contractile impairment. Whole-cell voltage clamp revealed reduced I(CaL); I(CaL) inhibition superimposed on ATR APs further suppressed [Ca(2+)](i) transients in control cells. Confocal microscopy indicated ATR-impaired propagation of the Ca(2+) release signal to the cell center in association with loss of t-tubular structures. Myofilament function studies in skinned permeabilized cardiomyocytes showed altered Ca(2+) sensitivity and force redevelopment in ATR, possibly due to hypophosphorylation of myosin-binding protein C and myosin light-chain protein 2a (immunoblot). Hypophosphorylation was related to multiple phosphorylation system abnormalities where protein kinase A regulatory subunits were downregulated, whereas autophosphorylation and expression of Ca(2+)-calmodulin-dependent protein kinase IIδ and protein phosphatase 1 activity were enhanced. Recovery of [Ca(2+)](i) transients and cell shortening occurred in parallel after ATR cessation., Conclusions: Shortening of APD contributes to hypocontractility induced by 1-week ATR but accounts for it only partially. Additional contractility-suppressing mechanisms include I(CaL) current reduction, impaired subcellular Ca(2+) signal transmission, and altered myofilament function associated with abnormal myosin and myosin-associated protein phosphorylation. The complex mechanistic basis of the atrial hypocontractility associated with AF argues for upstream therapeutic targeting rather than interventions directed toward specific downstream pathophysiological derangements.

Background: Congestive heart failure (CHF) is a common cause of atrial fibrillation. Focal sources of unknown mechanism have been described in CHF-related atrial fibrillation. The authors hypothesized that abnormal calcium (Ca(2+)) handling contributes to the CHF-related atrial arrhythmogenic substrate., Methods and Results: CHF was induced in dogs by ventricular tachypacing (240 bpm x2 weeks). Cellular Ca(2+)-handling properties and expression/phosphorylation status of key Ca(2+) handling and myofilament proteins were assessed in control and CHF atria. CHF decreased cell shortening but increased left atrial diastolic intracellular Ca(2+) concentration ([Ca(2+)](i)), [Ca(2+)](i) transient amplitude, and sarcoplasmic reticulum (SR) Ca(2+) load (caffeine-induced [Ca(2+)](i) release). SR Ca(2+) overload was associated with spontaneous Ca(2+) transient events and triggered ectopic activity, which was suppressed by the inhibition of SR Ca(2+) release (ryanodine) or Na(+)/Ca(2+) exchange. Mechanisms underlying abnormal SR Ca(2+) handling were then studied. CHF increased atrial action potential duration and action potential voltage clamp showed that CHF-like action potentials enhance Ca(2+)(i) loading. CHF increased calmodulin-dependent protein kinase II phosphorylation of phospholamban by 120%, potentially enhancing SR Ca(2+) uptake by reducing phospholamban inhibition of SR Ca(2+) ATPase, but it did not affect phosphorylation of SR Ca(2+)-release channels (RyR2). Total RyR2 and calsequestrin (main SR Ca(2+)-binding protein) expression were significantly reduced, by 65% and 15%, potentially contributing to SR dysfunction. CHF decreased expression of total and protein kinase A-phosphorylated myosin-binding protein C (a key contractile filament regulator) by 27% and 74%, potentially accounting for decreased contractility despite increased Ca(2+) transients. Complex phosphorylation changes were explained by enhanced calmodulin-dependent protein kinase IIdelta expression and function and type-1 protein-phosphatase activity but downregulated regulatory protein kinase A subunits., Conclusions: CHF causes profound changes in Ca(2+)-handling and -regulatory proteins that produce atrial fibrillation-promoting atrial cardiomyocyte Ca(2+)-handling abnormalities, arrhythmogenic triggered activity, and contractile dysfunction.

Background: A variety of strategies have been proposed to avoid the risks of pulmonary vein ablation for atrial fibrillation. The fall of impedance during radiofrequency catheter ablation can be used as a real time measure of tissue heating. The aim of this study was to analyze the impedance fall during ostial pulmonary vein ablation and to evaluate whether adjusting power to the fall of impedance may contribute to a reduction of the risk of complications., Methods: Analysis of biophysical parameters of ablation and determination of ostial diameters during follow-up were performed in 70 patients undergoing impedance-guided segmental ostial pulmonary vein ablation. Repeat radiographic angiography, local electrograms, and baseline impedance were the criteria to define the position of the 4-mm electrode tip at atrial sites or inside the proximal pulmonary veins., Results: Energy application inside the proximal pulmonary veins led to an increased impedance fall inside the first 5-10 mm of the pulmonary veins (1.1 +/- 0.5 Omega/W) as compared to ablation at atrial sites (0.7 +/- 0.3 Omega/W) (P < 0.01). The analysis of temperature and impedance fall during ostial ablation demonstrated an increased impedance fall with heating at sites inside the proximal pulmonary veins (1.5 +/- 0.6 Omega/ degrees C) as compared to atrial sites (1.2 +/- 0.5 Omega/ degrees C) (P < 0.001). The regression lines analyzing these correlations indicated that adjusting power to a maximum impedance fall of 20 Omega would limit heating at pulmonary venous sites to lower temperatures (average maximum temperature: 48 degrees C) than at atrial sites (average maximum temperature: 63 degrees C). The ablation strategy used for segmental ostial ablation in 70 patients, which involved power limitation to a maximum impedance fall of 20 Omega, allowed isolation of 89% of targeted pulmonary veins with a low rate of impedance rises (0.3% of applications). No pulmonary vein stenoses >30% were detected by follow-up computed tomography analysis., Conclusions: An increased impedance fall as the result of heating during ostial ablation was found inside the proximal pulmonary veins as compared to atrial sites. Adjusting power to the fall of impedance during segmental ostial pulmonary vein ablation contributes to the prevention of overheating inside the pulmonary veins and may lower the risk of coagulum formation and pulmonary vein stenosis.