1
|
Masè M, Cristoforetti A, Pelloni S, Ravelli F. Systematic in-silico evaluation of fibrosis effects on re-entrant wave dynamics in atrial tissue. Sci Rep 2024; 14:11427. [PMID: 38763959 DOI: 10.1038/s41598-024-62002-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 05/13/2024] [Indexed: 05/21/2024] Open
Abstract
Despite the key role of fibrosis in atrial fibrillation (AF), the effects of different spatial distributions and textures of fibrosis on wave propagation mechanisms in AF are not fully understood. To clarify these aspects, we performed a systematic computational study to assess fibrosis effects on the characteristics and stability of re-entrant waves in electrically-remodelled atrial tissues. A stochastic algorithm, which generated fibrotic distributions with controlled overall amount, average size, and orientation of fibrosis elements, was implemented on a monolayer spheric atrial model. 245 simulations were run at changing fibrosis parameters. The emerging propagation patterns were quantified in terms of rate, regularity, and coupling by frequency-domain analysis of correspondent synthetic bipolar electrograms. At the increase of fibrosis amount, the rate of reentrant waves significantly decreased and higher levels of regularity and coupling were observed (p < 0.0001). Higher spatial variability and pattern stochasticity over repetitions was observed for larger amount of fibrosis, especially in the presence of patchy and compact fibrosis. Overall, propagation slowing and organization led to higher stability of re-entrant waves. These results strengthen the evidence that the amount and spatial distribution of fibrosis concur in dictating re-entry dynamics in remodeled tissue and represent key factors in AF maintenance.
Collapse
Affiliation(s)
- Michela Masè
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy.
| | - Alessandro Cristoforetti
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy
| | - Samuele Pelloni
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy
| | - Flavia Ravelli
- Laboratory of Biophysics and Translational Cardiology, Department of Cellular, Computational and Integrative Biology-CIBIO, University of Trento, Via Sommarive 18, 38123, Povo, Trento, Italy
- CISMed-Centre for Medical Sciences, University of Trento, 38122, Trento, Italy
| |
Collapse
|
2
|
Escribano P, Ródenas J, García M, Hornero F, Gracia-Baena JM, Alcaraz R, Rieta JJ. Novel Entropy-Based Metrics for Long-Term Atrial Fibrillation Recurrence Prediction Following Surgical Ablation: Insights from Preoperative Electrocardiographic Analysis. ENTROPY (BASEL, SWITZERLAND) 2023; 26:28. [PMID: 38248154 PMCID: PMC11154238 DOI: 10.3390/e26010028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/23/2023] [Accepted: 12/26/2023] [Indexed: 01/23/2024]
Abstract
Atrial fibrillation (AF) is a prevalent cardiac arrhythmia often treated concomitantly with other cardiac interventions through the Cox-Maze procedure. This highly invasive intervention is still linked to a long-term recurrence rate of approximately 35% in permanent AF patients. The aim of this study is to preoperatively predict long-term AF recurrence post-surgery through the analysis of atrial activity (AA) organization from non-invasive electrocardiographic (ECG) recordings. A dataset comprising ECGs from 53 patients with permanent AF who had undergone Cox-Maze concomitant surgery was analyzed. The AA was extracted from the lead V1 of these recordings and then characterized using novel predictors, such as the mean and standard deviation of the relative wavelet energy (RWEm and RWEs) across different scales, and an entropy-based metric that computes the stationary wavelet entropy variability (SWEnV). The individual predictors exhibited limited predictive capabilities to anticipate the outcome of the procedure, with the SWEnV yielding a classification accuracy (Acc) of 68.07%. However, the assessment of the RWEs for the seventh scale (RWEs7), which encompassed frequencies associated with the AA, stood out as the most promising individual predictor, with sensitivity (Se) and specificity (Sp) values of 80.83% and 67.09%, respectively, and an Acc of almost 75%. Diverse multivariate decision tree-based models were constructed for prediction, giving priority to simplicity in the interpretation of the forecasting methodology. In fact, the combination of the SWEnV and RWEs7 consistently outperformed the individual predictors and excelled in predicting post-surgery outcomes one year after the Cox-Maze procedure, with Se, Sp, and Acc values of approximately 80%, thus surpassing the results of previous studies based on anatomical predictors associated with atrial function or clinical data. These findings emphasize the crucial role of preoperative patient-specific ECG signal analysis in tailoring post-surgical care, enhancing clinical decision making, and improving long-term clinical outcomes.
Collapse
Affiliation(s)
- Pilar Escribano
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain; (P.E.); (J.R.); (M.G.); (R.A.)
| | - Juan Ródenas
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain; (P.E.); (J.R.); (M.G.); (R.A.)
| | - Manuel García
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain; (P.E.); (J.R.); (M.G.); (R.A.)
| | - Fernando Hornero
- Cardiovascular Surgery Department, Hospital Clínico Universitario de Valencia, 46010 Valencia, Spain; (F.H.); (J.M.G.-B.)
| | - Juan M. Gracia-Baena
- Cardiovascular Surgery Department, Hospital Clínico Universitario de Valencia, 46010 Valencia, Spain; (F.H.); (J.M.G.-B.)
| | - Raúl Alcaraz
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain; (P.E.); (J.R.); (M.G.); (R.A.)
| | - José J. Rieta
- BioMIT.org, Electronic Engineering Department, Universitat Politecnica de Valencia, 46022 Valencia, Spain
| |
Collapse
|
3
|
Pancorbo L, Ruipérez-Campillo S, Tormos Á, Guill A, Cervigón R, Alberola A, Chorro FJ, Millet J, Castells F. Vector Field Heterogeneity for the Assessment of Locally Disorganised Cardiac Electrical Propagation Wavefronts From High-Density Multielectrodes. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2023; 5:32-44. [PMID: 38445238 PMCID: PMC10914212 DOI: 10.1109/ojemb.2023.3344349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/22/2023] [Accepted: 11/28/2023] [Indexed: 03/07/2024] Open
Abstract
High-density multielectrode catheters are becoming increasingly popular in cardiac electrophysiology for advanced characterisation of the cardiac tissue, due to their potential to identify impaired sites. These are often characterised by abnormal electrical conduction, which may cause locally disorganised propagation wavefronts. To quantify it, a novel heterogeneity parameter based on vector field analysis is proposed, utilising finite differences to measure direction changes between adjacent cliques. The proposed Vector Field Heterogeneity metric has been evaluated on a set of simulations with controlled levels of organisation in vector maps, and a variety of grid sizes. Furthermore, it has been tested on animal experimental models of isolated Langendorff-perfused rabbit hearts. The proposed parameter exhibited superior capturing ability of heterogeneous propagation wavefronts compared to the classical Spatial Inhomogeneity Index, and simulations proved that the metric effectively captures gradual increments in disorganisation in propagation patterns. Notably, it yielded robust and consistent outcomes for [Formula: see text] grid sizes, underscoring its suitability for the latest generation of orientation-independent cardiac catheters.
Collapse
Affiliation(s)
- Lucía Pancorbo
- ITACA InstituteUniversitat Politècnica de València46022ValenciaSpain
| | | | - Álvaro Tormos
- ITACA InstituteUniversitat Politècnica de València46022ValenciaSpain
| | - Antonio Guill
- ITACA InstituteUniversitat Politècnica de València46022ValenciaSpain
| | | | - Antonio Alberola
- Departamento de FisiologíaUniversidad de València46010ValenciaSpain
- Instituto de Investigación INCLIVA46010ValenciaSpain
- CIBER E. Cardiovasculares28029MadridSpain
| | - Francisco Javier Chorro
- CIBER E. Cardiovasculares28029MadridSpain
- Departamento de MedicinaUniversidad de València46010ValenciaSpain
- Instituto de Investigación INCLIVA46010ValenciaSpain
- Servicio de CardiologíaHospital Clínic Universitari de València46010ValenciaSpain
| | - José Millet
- ITACA InstituteUniversitat Politècnica de València46022ValenciaSpain
- Centro de Investigación Biomédica en Red Enfermedades Cardiovascular28029MadridSpain
| | | |
Collapse
|
4
|
Zhong G, Feng X, Yuan H, Yang C. A 3D-CNN with temporal-attention block to predict the recurrence of atrial fibrillation based on body-surface potential mapping signals. Front Physiol 2022; 13:1030307. [DOI: 10.3389/fphys.2022.1030307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022] Open
Abstract
Catheter ablation has become an important treatment for atrial fibrillation (AF), but its recurrence rate is still high. The aim of this study was to predict AF recurrence using a three-dimensional (3D) network model based on body-surface potential mapping signals (BSPMs). BSPMs were recorded with a 128-lead vest in 14 persistent AF patients before undergoing catheter ablation (Maze-IV). The torso geometry was acquired and meshed by point cloud technology, and the BSPM was interpolated into the torso geometry by the inverse distance weighted (IDW) method to generate the isopotential map. Experiments show that the isopotential map of BSPMs can reflect the propagation of the electrical wavefronts. The 3D isopotential sequence map was established by combining the spatial–temporal information of the isopotential map; a 3D convolutional neural network (3D-CNN) model with temporal attention was established to predict AF recurrence. Our study proposes a novel attention block that focuses the characteristics of atrial activations to improve sampling accuracy. In our experiment, accuracy (ACC) in the intra-patient evaluation for predicting the recurrence of AF was 99.38%. In the inter-patient evaluation, ACC of 3D-CNN was 81.48%, and the area under the curve (AUC) was 0.88. It can be concluded that the dynamic rendering of multiple isopotential maps can not only comprehensively display the conduction of cardiac electrical activity on the body surface but also successfully predict the recurrence of AF after CA by using 3D isopotential sequence maps.
Collapse
|
5
|
Escribano P, Ródenas J, García M, Arias MA, Hidalgo VM, Calero S, Rieta JJ, Alcaraz R. Preoperative Prediction of Catheter Ablation Outcome in Persistent Atrial Fibrillation Patients through Spectral Organization Analysis of the Surface Fibrillatory Waves. J Pers Med 2022; 12:jpm12101721. [PMID: 36294860 PMCID: PMC9604697 DOI: 10.3390/jpm12101721] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022] Open
Abstract
Catheter ablation (CA) is a commonly used treatment for persistent atrial fibrillation (AF). Since its medium/long-term success rate remains limited, preoperative prediction of its outcome is gaining clinical interest to optimally select candidates for the procedure. Among predictors based on the surface electrocardiogram, the dominant frequency (DF) and harmonic exponential decay (γ) of the fibrillatory waves (f-waves) have reported promising but clinically insufficient results. Hence, the main goal of this work was to conduct a broader analysis of the f-wave harmonic spectral structure to improve CA outcome prediction through several entropy-based measures computed on different frequency bands. On a database of 151 persistent AF patients under radio-frequency CA and a follow-up of 9 months, the newly introduced parameters discriminated between patients who relapsed to AF and those who maintained SR at about 70%, which was statistically superior to the DF and approximately similar to γ. They also provided complementary information to γ through different combinations in multivariate models based on lineal discriminant analysis and report classification performance improvement of about 5%. These results suggest that the presence of larger harmonics and a proportionally smaller DF peak is associated with a decreased probability of AF recurrence after CA.
Collapse
Affiliation(s)
- Pilar Escribano
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain
- Correspondence:
| | - Juan Ródenas
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain
| | - Manuel García
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain
| | - Miguel A. Arias
- Cardiac Arrhythmia Department, Complejo Hospitalario Universitario de Toledo, 45007 Toledo, Spain
| | - Víctor M. Hidalgo
- Cardiac Arrhythmia Department, Complejo Hospitalario Universitario de Albacete, 02006 Albacete, Spain
| | - Sofía Calero
- Cardiac Arrhythmia Department, Complejo Hospitalario Universitario de Albacete, 02006 Albacete, Spain
| | - José J. Rieta
- BioMIT.org, Electronic Engineering Department, Universitat Politecnica de Valencia, 46022 Valencia, Spain
| | - Raúl Alcaraz
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, 02071 Albacete, Spain
| |
Collapse
|
6
|
Correlation between conduction velocity and frequency analysis in patients with atrial fibrillation using high-density charge mapping. Med Biol Eng Comput 2022; 60:3081-3090. [DOI: 10.1007/s11517-022-02659-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 08/22/2022] [Indexed: 10/14/2022]
|
7
|
Chu GS, Li X, Stafford PJ, Vanheusden FJ, Salinet JL, Almeida TP, Dastagir N, Sandilands AJ, Kirchhof P, Schlindwein FS, Ng GA. Simultaneous Whole-Chamber Non-contact Mapping of Highest Dominant Frequency Sites During Persistent Atrial Fibrillation: A Prospective Ablation Study. Front Physiol 2022; 13:826449. [PMID: 35370796 PMCID: PMC8966840 DOI: 10.3389/fphys.2022.826449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/21/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose Sites of highest dominant frequency (HDF) are implicated by many proposed mechanisms underlying persistent atrial fibrillation (persAF). We hypothesized that prospectively identifying and ablating dynamic left atrial HDF sites would favorably impact the electrophysiological substrate of persAF. We aim to assess the feasibility of prospectively identifying HDF sites by global simultaneous left atrial mapping. Methods PersAF patients with no prior ablation history underwent global simultaneous left atrial non-contact mapping. 30 s of electrograms recorded during AF were exported into a bespoke MATLAB interface to identify HDF regions, which were then targeted for ablation, prior to pulmonary vein isolation. Following ablation of each region, change in AF cycle length (AFCL) was documented (≥ 10 ms considered significant). Baseline isopotential maps of ablated regions were retrospectively analyzed looking for rotors and focal activation or extinction events. Results A total of 51 HDF regions were identified and ablated in 10 patients (median DF 5.8Hz, range 4.4-7.1Hz). An increase in AFCL of was seen in 20 of the 51 regions (39%), including AF termination in 4 patients. 5 out of 10 patients (including the 4 patients where AF termination occurred with HDF-guided ablation) were free from AF recurrence at 1 year. The proportion of HDF occurrences in an ablated region was not associated with change in AFCL (τ = 0.11, p = 0.24). Regions where AFCL decreased by 10 ms or more (i.e., AF disorganization) after ablation also showed lowest baseline spectral organization (p < 0.033 for any comparison). Considering all ablated regions, the average proportion of HDF events which were also HRI events was 8.0 ± 13%. Focal activations predominated (537/1253 events) in the ablated regions on isopotential maps, were modestly associated with the proportion of HDF occurrences represented by the ablated region (Kendall's τ = 0.40, p < 0.0001), and very strongly associated with focal extinction events (τ = 0.79, p < 0.0001). Rotors were rare (4/1253 events). Conclusion Targeting dynamic HDF sites is feasible and can be efficacious, but lacks specificity in identifying relevant human persAF substrate. Spectral organization may have an adjunctive role in preventing unnecessary substrate ablation. Dynamic HDF sites are not associated with observable rotational activity on isopotential mapping, but epi-endocardial breakthroughs could be contributory.
Collapse
Affiliation(s)
- Gavin S. Chu
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- Lancashire Cardiac Centre, Blackpool Teaching Hospitals NHS Foundation Trust, Blackpool, United Kingdom
| | - Xin Li
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- School of Engineering, University of Leicester, Leicester, United Kingdom
| | - Peter J. Stafford
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | | | - João L. Salinet
- Center for Engineering, Modeling and Applied Social Sciences, University Federal of ABC, Santo André, Brazil
| | - Tiago P. Almeida
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- School of Engineering, University of Leicester, Leicester, United Kingdom
| | - Nawshin Dastagir
- Department of International Foundation, Massey University, Auckland, New Zealand
| | - Alastair J. Sandilands
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Paulus Kirchhof
- University Heart and Vascular Centre, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fernando S. Schlindwein
- School of Engineering, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - G. André Ng
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| |
Collapse
|
8
|
Diaz-Maue L, Steinebach J, Richter C. Patterned Illumination Techniques in Optogenetics: An Insight Into Decelerating Murine Hearts. Front Physiol 2022; 12:750535. [PMID: 35087413 PMCID: PMC8787046 DOI: 10.3389/fphys.2021.750535] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 12/02/2021] [Indexed: 11/21/2022] Open
Abstract
Much has been reported about optogenetic based cardiac arrhythmia treatment and the corresponding characterization of photostimulation parameters, but still, our capacity to interact with the underlying spatiotemporal excitation patterns relies mainly on electrical and/or pharmacological approaches. However, these well-established treatments have always been an object of somehow heated discussions. Though being acutely life-saving, they often come with potential side-effects leading to a decreased functionality of the complex cardiac system. Recent optogenetic studies showed the feasibility of the usage of photostimulation as a defibrillation method with comparatively high success rates. Although, these studies mainly concentrated on the description as well as on the comparison of single photodefibrillation approaches, such as locally focused light application and global illumination, less effort was spent on the description of excitation patterns during actual photostimulation. In this study, the authors implemented a multi-site photodefibrillation technique in combination with Multi-Lead electrocardiograms (ECGs). The technical connection of real-time heart rhythm measurements and the arrhythmia counteracting light control provides a further step toward automated arrhythmia classification, which can lead to adaptive photodefibrillation methods. In order to show the power effectiveness of the new approach, transgenic murine hearts expressing channelrhodopsin-2 ex vivo were investigated using circumferential micro-LED and ECG arrays. Thus, combining the best of two methods by giving the possibility to illuminate either locally or globally with differing pulse parameters. The optical technique presented here addresses a number of challenges of technical cardiac optogenetics and is discussed in the context of arrhythmic development during photostimulation.
Collapse
Affiliation(s)
- Laura Diaz-Maue
- Department of Research Electronics, Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany.,Biomedical Physics Research Group, Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK e., V.), Göttingen, Germany
| | - Janna Steinebach
- Biomedical Physics Research Group, Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Claudia Richter
- German Center for Cardiovascular Research (DZHK e., V.), Göttingen, Germany.,Laboratory Animal Science Unit, German Primate Center, Leibniz-Institute for Primate Research, Göttingen, Germany
| |
Collapse
|
9
|
de Groot NMS, Shah D, Boyle PM, Anter E, Clifford GD, Deisenhofer I, Deneke T, van Dessel P, Doessel O, Dilaveris P, Heinzel FR, Kapa S, Lambiase PD, Lumens J, Platonov PG, Ngarmukos T, Martinez JP, Sanchez AO, Takahashi Y, Valdigem BP, van der Veen AJ, Vernooy K, Casado-Arroyo Co-Chair R. Critical appraisal of technologies to assess electrical activity during atrial fibrillation: a position paper from the European Heart Rhythm Association and European Society of Cardiology Working Group on eCardiology in collaboration with the Heart Rhythm Society, Asia Pacific Heart Rhythm Society, Latin American Heart Rhythm Society and Computing in Cardiology. Europace 2021; 24:313-330. [PMID: 34878119 DOI: 10.1093/europace/euab254] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
We aim to provide a critical appraisal of basic concepts underlying signal recording and processing technologies applied for (i) atrial fibrillation (AF) mapping to unravel AF mechanisms and/or identifying target sites for AF therapy and (ii) AF detection, to optimize usage of technologies, stimulate research aimed at closing knowledge gaps, and developing ideal AF recording and processing technologies. Recording and processing techniques for assessment of electrical activity during AF essential for diagnosis and guiding ablative therapy including body surface electrocardiograms (ECG) and endo- or epicardial electrograms (EGM) are evaluated. Discussion of (i) differences in uni-, bi-, and multi-polar (omnipolar/Laplacian) recording modes, (ii) impact of recording technologies on EGM morphology, (iii) global or local mapping using various types of EGM involving signal processing techniques including isochronal-, voltage- fractionation-, dipole density-, and rotor mapping, enabling derivation of parameters like atrial rate, entropy, conduction velocity/direction, (iv) value of epicardial and optical mapping, (v) AF detection by cardiac implantable electronic devices containing various detection algorithms applicable to stored EGMs, (vi) contribution of machine learning (ML) to further improvement of signals processing technologies. Recording and processing of EGM (or ECG) are the cornerstones of (body surface) mapping of AF. Currently available AF recording and processing technologies are mainly restricted to specific applications or have technological limitations. Improvements in AF mapping by obtaining highest fidelity source signals (e.g. catheter-electrode combinations) for signal processing (e.g. filtering, digitization, and noise elimination) is of utmost importance. Novel acquisition instruments (multi-polar catheters combined with improved physical modelling and ML techniques) will enable enhanced and automated interpretation of EGM recordings in the near future.
Collapse
Affiliation(s)
- Natasja M S de Groot
- Department of Cardiology, Erasmus University Medical Centre, Rotterdam, Delft University of Technology, Delft the Netherlands
| | - Dipen Shah
- Cardiology Service, University Hospitals Geneva, Geneva, Switzerland
| | - Patrick M Boyle
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Elad Anter
- Cardiac Electrophysiology Section, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio, USA
| | - Gari D Clifford
- Department of Biomedical Informatics, Emory University, Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, USA
| | - Isabel Deisenhofer
- Department of Electrophysiology, German Heart Center Munich and Technical University of Munich, Munich, Germany
| | - Thomas Deneke
- Department of Cardiology, Rhon-klinikum Campus Bad Neustadt, Germany
| | - Pascal van Dessel
- Department of Cardiology, Medisch Spectrum Twente, Twente, the Netherlands
| | - Olaf Doessel
- Karlsruher Institut für Technologie (KIT), Karlsruhe, Germany
| | - Polychronis Dilaveris
- 1st University Department of Cardiology, National & Kapodistrian University of Athens School of Medicine, Hippokration Hospital, Athens, Greece
| | - Frank R Heinzel
- Department of Internal Medicine and Cardiology, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum and DZHK (German Centre for Cardiovascular Research), Berlin, Germany
| | - Suraj Kapa
- Department of Cardiology, Mayo Clinic, Rochester, USA
| | | | - Joost Lumens
- Cardiovascular Research Institute Maastricht (CARIM) Maastricht University, Maastricht, the Netherlands
| | - Pyotr G Platonov
- Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden
| | - Tachapong Ngarmukos
- Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Juan Pablo Martinez
- Aragon Institute of Engineering Research/IIS-Aragon and University of Zaragoza, Zaragoza, Spain, CIBER Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza, Spain
| | - Alejandro Olaya Sanchez
- Department of Cardiology, Hospital San José, Fundacion Universitaia de Ciencas de la Salud, Bogota, Colombia
| | - Yoshihide Takahashi
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Bruno P Valdigem
- Department of Cardiology, Hospital Rede D'or São Luiz, hospital Albert einstein and Dante pazzanese heart institute, São Paulo, Brasil
| | - Alle-Jan van der Veen
- Department Circuits and Systems, Delft University of Technology, Delft, the Netherlands
| | - Kevin Vernooy
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Centre, Maastricht, the Netherlands
| | | | | |
Collapse
|
10
|
Palacio LC, Ugarte JP, Saiz J, Tobón C. The Effects of Fibrotic Cell Type and Its Density on Atrial Fibrillation Dynamics: An In Silico Study. Cells 2021; 10:cells10102769. [PMID: 34685750 PMCID: PMC8534881 DOI: 10.3390/cells10102769] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/03/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Remodeling in atrial fibrillation (AF) underlines the electrical and structural changes in the atria, where fibrosis is a hallmark of arrhythmogenic structural alterations. Fibrosis is an important feature of the AF substrate and can lead to abnormal conduction and, consequently, mechanical dysfunction. The fibrotic process comprises the presence of fibrotic cells, including fibroblasts, myofibroblasts and fibrocytes, which play an important role during fibrillatory dynamics. This work assesses the effect of the diffuse fibrosis density and the intermingled presence of the three types of fibrotic cells on the dynamics of persistent AF. For this purpose, the three fibrotic cells were electrically coupled to cardiomyocytes in a 3D realistic model of human atria. Low (6.25%) and high (25%) fibrosis densities were implemented in the left atrium according to a diffuse fibrosis representation. We analyze the action potential duration, conduction velocity and fibrillatory conduction patterns. Additionally, frequency analysis was performed in 50 virtual electrograms. The tested fibrosis configurations generated a significant conduction velocity reduction, where the larger effect was observed at high fibrosis density (up to 82% reduction in the fibrocytes configuration). Increasing the fibrosis density intensifies the vulnerability to multiple re-entries, zigzag propagation, and chaotic activity in the fibrillatory conduction. The most complex propagation patterns were observed at high fibrosis densities and the fibrocytes are the cells with the largest proarrhythmic effect. Left-to-right dominant frequency gradients can be observed for all fibrosis configurations, where the fibrocytes configuration at high density generates the most significant gradients (up to 4.5 Hz). These results suggest the important role of different fibrotic cell types and their density in diffuse fibrosis on the chaotic propagation patterns during persistent AF.
Collapse
Affiliation(s)
- Laura C. Palacio
- Materiales Nanoestructurados y Biomodelación (MATBIOM), Universidad de Medellín, Medellín 050032, Colombia;
| | - Juan P. Ugarte
- Grupo de Investigación en Modelamiento y Simulación Computacional (GIMSC), Universidad de San Buenaventura, Medellín 050010, Colombia;
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería (CIB), Universitat Politècnica de València, 46022 Valencia, Spain;
| | - Catalina Tobón
- Materiales Nanoestructurados y Biomodelación (MATBIOM), Universidad de Medellín, Medellín 050032, Colombia;
- Correspondence:
| |
Collapse
|
11
|
Prediction of atrial fibrillation inducibility using spatiotemporal activation analysis combined with network mapping. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
12
|
Li X, Chu GS, Almeida TP, Vanheusden FJ, Salinet J, Dastagir N, Mistry AR, Vali Z, Sidhu B, Stafford PJ, Schlindwein FS, Ng GA. Automatic Extraction of Recurrent Patterns of High Dominant Frequency Mapping During Human Persistent Atrial Fibrillation. Front Physiol 2021; 12:649486. [PMID: 33776801 PMCID: PMC7994862 DOI: 10.3389/fphys.2021.649486] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/22/2021] [Indexed: 11/30/2022] Open
Abstract
Purpose: Identifying targets for catheter ablation remains challenging in persistent atrial fibrillation (persAF). The dominant frequency (DF) of atrial electrograms during atrial fibrillation (AF) is believed to primarily reflect local activation. Highest DF (HDF) might be responsible for the initiation and perpetuation of persAF. However, the spatiotemporal behavior of DF remains not fully understood. Some DFs during persAF were shown to lack spatiotemporal stability, while others exhibit recurrent behavior. We sought to develop a tool to automatically detect recurrent DF patterns in persAF patients. Methods: Non-contact mapping of the left atrium (LA) was performed in 10 patients undergoing persAF HDF ablation. 2,048 virtual electrograms (vEGMs, EnSite Array, Abbott Laboratories, USA) were collected for up to 5 min before and after ablation. Frequency spectrum was estimated using fast Fourier transform and DF was identified as the peak between 4 and 10 Hz and organization index (OI) was calculated. The HDF maps were identified per 4-s window and an automated pattern recognition algorithm was used to find recurring HDF spatial patterns. Dominant patterns (DPs) were defined as the HDF pattern with the highest recurrence. Results: DPs were found in all patients. Patients in atrial flutter after ablation had a single DP over the recorded time period. The time interval (median [IQR]) of DP recurrence for the patients in AF after ablation (7 patients) decreased from 21.1 s [11.8 49.7 s] to 15.7 s [6.5 18.2 s]. The DF inside the DPs presented lower temporal standard deviation (0.18 ± 0.06 Hz vs. 0.29 ± 0.12 Hz, p < 0.05) and higher OI (0.35 ± 0.03 vs. 0.31 ± 0.04, p < 0.05). The atrial regions with the highest proportion of HDF region were the septum and the left upper pulmonary vein. Conclusion: Multiple recurrent spatiotemporal HDF patterns exist during persAF. The proposed method can identify and quantify the spatiotemporal repetition of the HDFs, where the high recurrences of DP may suggest a more organized rhythm. DPs presented a more consistent DF and higher organization compared with non-DPs, suggesting that DF with higher OI might be more likely to recur. Recurring patterns offer a more comprehensive dynamic insight of persAF behavior, and ablation targeting such regions may be beneficial.
Collapse
Affiliation(s)
- Xin Li
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- School of Engineering, University of Leicester, Leicester, United Kingdom
| | - Gavin S. Chu
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
| | - Tiago P. Almeida
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- School of Engineering, University of Leicester, Leicester, United Kingdom
| | | | - João Salinet
- Biomedical Engineering, Centre for Engineering, Modelling and Applied Social Sciences (CECS), Federal University of ABC, Santo André, Brazil
| | - Nawshin Dastagir
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Amar R. Mistry
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
| | - Zakariyya Vali
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Bharat Sidhu
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
| | - Peter J. Stafford
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Fernando S. Schlindwein
- School of Engineering, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - G. André Ng
- Department of Cardiovascular Science, University of Leicester, Leicester, United Kingdom
- National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| |
Collapse
|
13
|
Abstract
Pharmacologic management of atrial fibrillation (AF) is a pressing problem. This arrhythmia afflicts >5 million individuals in the United States and prevalence is estimated to rise to 12 million by 2050. Although the pill-in-the-pocket regimen for self-administered AF cardioversion introduced over a decade ago has proven useful, significant drawbacks exist. Among these are the relatively long latency of effects in the range of hours along with potential for hypotension and other adverse effects. This experience prompted development of a new strategy for increasing plasma concentrations of antiarrhythmic drugs rapidly and for a limited time, namely, pulmonary delivery. In preclinical studies in Yorkshire pigs, intratracheal administration of flecainide was shown to cause a rapid, reproducible increase in plasma drug levels. Moreover, pulmonary delivery of flecainide converted AF to normal sinus rhythm by prolonging atrial depolarization, which slows intra-atrial conduction and seems to be directly correlated with efficacy in converting AF. The rapid rise in plasma flecainide levels optimizes its anti-AF effects while minimizing adverse influences on ventricular depolarization and contractility. A more concentrated and soluble formulation of flecainide using a novel cyclodextrin complex excipient reduced net drug delivery for AF conversion when compared to the acetate formulation. Inhalation of the beta-adrenergic blocking agent metoprolol slows ventricular rate and can also terminate AF. In human subjects, oral inhalation of flecainide acetate with a hand-held, breath-actuated nebulizer results in signature prolongation of the QRS complex without serious adverse events. Thus, pulmonary delivery is a promising advance in pharmacologic approach to management of AF.
Collapse
|
14
|
|
15
|
Pulmonary Delivery of Metoprolol Reduces Ventricular Rate During Atrial Fibrillation and Accelerates Conversion to Sinus Rhythm. J Cardiovasc Pharmacol 2020; 75:135-140. [DOI: 10.1097/fjc.0000000000000780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
16
|
Gussak G, Pfenniger A, Wren L, Gilani M, Zhang W, Yoo S, Johnson DA, Burrell A, Benefield B, Knight G, Knight BP, Passman R, Goldberger JJ, Aistrup G, Wasserstrom JA, Shiferaw Y, Arora R. Region-specific parasympathetic nerve remodeling in the left atrium contributes to creation of a vulnerable substrate for atrial fibrillation. JCI Insight 2019; 4:130532. [PMID: 31503549 DOI: 10.1172/jci.insight.130532] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/27/2019] [Indexed: 12/27/2022] Open
Abstract
Atrial fibrillation (AF) is the most common heart rhythm disorder and a major cause of stroke. Unfortunately, current therapies for AF are suboptimal, largely because the molecular mechanisms underlying AF are poorly understood. Since the autonomic nervous system is thought to increase vulnerability to AF, we used a rapid atrial pacing (RAP) canine model to investigate the anatomic and electrophysiological characteristics of autonomic remodeling in different regions of the left atrium. RAP led to marked hypertrophy of parent nerve bundles in the posterior left atrium (PLA), resulting in a global increase in parasympathetic and sympathetic innervation throughout the left atrium. Parasympathetic fibers were more heterogeneously distributed in the PLA when compared with other left atrial regions; this led to greater fractionation and disorganization of AF electrograms in the PLA. Computational modeling revealed that heterogeneously distributed parasympathetic activity exacerbates sympathetic substrate for wave break and reentry. We further discovered that levels of nerve growth factor (NGF) were greatest in the left atrial appendage (LAA), where AF was most organized. Preferential NGF release by the LAA - likely a direct function of frequency and regularity of atrial stimulation - may have important implications for creation of a vulnerable AF substrate.
Collapse
Affiliation(s)
- Georg Gussak
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Anna Pfenniger
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lisa Wren
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Mehul Gilani
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Wenwei Zhang
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Shin Yoo
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - David A Johnson
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Amy Burrell
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Brandon Benefield
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gabriel Knight
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Bradley P Knight
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Rod Passman
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Gary Aistrup
- Masonic Medical Research Institute, Utica, New York, USA
| | - J Andrew Wasserstrom
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yohannes Shiferaw
- Department of Physics, California State University, Northridge, California, USA
| | - Rishi Arora
- Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| |
Collapse
|
17
|
Podziemski P, Zeemering S, Kuklik P, van Hunnik A, Maesen B, Maessen J, Crijns HJ, Verheule S, Schotten U. Rotors Detected by Phase Analysis of Filtered, Epicardial Atrial Fibrillation Electrograms Colocalize With Regions of Conduction Block. Circ Arrhythm Electrophysiol 2019; 11:e005858. [PMID: 30354409 PMCID: PMC6553551 DOI: 10.1161/circep.117.005858] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Several recent studies suggest rotors detected by phase mapping may act as main drivers of persistent atrial fibrillation. However, the electrophysiological nature of detected rotors remains unclear. We performed a direct, 1:1 comparison between phase and activation time mapping in high-density, epicardial, direct-contact mapping files of human atrial fibrillation. METHODS Thirty-eight unipolar electrogram files of 10 s duration were recorded in patients with atrial fibrillation (n=20 patients) using a 16×16 electrode array placed on the epicardial surface of the left atrial posterior wall or the right atrial free wall. Phase maps and isochrone wave maps were constructed for all recordings. For each detected phase singularity (PS) with a lifespan of >1 cycle length, the corresponding conduction pattern was investigated in the isochrone wave maps. RESULTS When using sinusoidal recomposition and Hilbert Transform, 138 PSs were detected. One hundred and four out of 138 PSs were detected within 1 electrode distance (1.5 mm) from a line of conduction block between nonrotating wavefronts detected by activation mapping. Far fewer rotating wavefronts were detected when rotating activity was identified based on wave mapping (18 out of 8219 detected waves). Fourteen out of these 18 cases were detected as PSs in phase mapping. Phase analysis of filtered electrograms produced by simulated wavefronts separated by conduction block also identified PSs on the line of conduction block. CONCLUSIONS PSs identified by phase analysis of filtered epicardial electrograms colocalize with conduction block lines identified by activation mapping. Detection of PSs using phase analysis has a low specificity for identifying rotating wavefronts during human atrial fibrillation using activation mapping.
Collapse
Affiliation(s)
- Piotr Podziemski
- Department of Physiology, Maastricht University, the Netherlands (P.P., S.Z., A.v.H., S.V.).,Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.)
| | - Stef Zeemering
- Department of Physiology, Maastricht University, the Netherlands (P.P., S.Z., A.v.H., S.V.).,Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.)
| | - Pawel Kuklik
- Department of Cardiology, Electrophysiology, University Medical Center Hamburg-Eppendorf, Germany (P.K.)
| | - Arne van Hunnik
- Department of Physiology, Maastricht University, the Netherlands (P.P., S.Z., A.v.H., S.V.).,Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.)
| | - Bart Maesen
- Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.).,Department of Cardiothoracic Surgery, Maastricht University Medical Center, the Netherlands (B.M., J.M.)
| | - Jos Maessen
- Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.).,Department of Cardiothoracic Surgery, Maastricht University Medical Center, the Netherlands (B.M., J.M.)
| | - Harry J Crijns
- Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.).,Department of Cardiology, Maastricht University Medical Center, the Netherlands (H.J.C.)
| | - Sander Verheule
- Department of Physiology, Maastricht University, the Netherlands (P.P., S.Z., A.v.H., S.V.).,Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.)
| | - Ulrich Schotten
- Department of Physiology, Maastricht University, the Netherlands (P.P., S.Z., A.v.H., S.V.).,Cardiovascular Research Institute Maastricht (CARIM), the Netherlands (P.P., S.Z., A.v.H., B.M., J.M., H.J.C., S.V., U.S.)
| |
Collapse
|
18
|
Martínez-Iniesta M, Ródenas J, Rieta JJ, Alcaraz R. The stationary wavelet transform as an efficient reductor of powerline interference for atrial bipolar electrograms in cardiac electrophysiology. Physiol Meas 2019; 40:075003. [PMID: 31239416 DOI: 10.1088/1361-6579/ab2cb8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The most relevant source of signal contamination in the cardiac electrophysiology (EP) laboratory is the ubiquitous powerline interference (PLI). To reduce this perturbation, algorithms including common fixed-bandwidth and adaptive-notch filters have been proposed. Although such methods have proven to add artificial fractionation to intra-atrial electrograms (EGMs), they are still frequently used. However, such morphological alteration can conceal the accurate interpretation of EGMs, specially to evaluate the mechanisms supporting atrial fibrillation (AF), which is the most common cardiac arrhythmia. Given the clinical relevance of AF, a novel algorithm aimed at reducing PLI on highly contaminated bipolar EGMs and, simultaneously, preserving their morphology is proposed. APPROACH The method is based on the wavelet shrinkage and has been validated through customized indices on a set of synthesized EGMs to accurately quantify the achieved level of PLI reduction and signal morphology alteration. Visual validation of the algorithm's performance has also been included for some real EGM excerpts. MAIN RESULTS The method has outperformed common filtering-based and wavelet-based strategies in the analyzed scenario. Moreover, it possesses advantages such as insensitivity to amplitude and frequency variations in the PLI, and the capability of joint removal of several interferences. SIGNIFICANCE The use of this algorithm in routine cardiac EP studies may enable improved and truthful evaluation of AF mechanisms.
Collapse
Affiliation(s)
- Miguel Martínez-Iniesta
- Research Group in Electronic, Biomedical and Telecommunication Engineering, University of Castilla-La Mancha, Albacete, Spain
| | | | | | | |
Collapse
|
19
|
Verrier RL, Bortolotto AL, Silva BA, Marum AA, Stocco FG, Evaristo E, de Antonio VZ, Silva AC, Belardinelli L. Accelerated conversion of atrial fibrillation to normal sinus rhythm by pulmonary delivery of flecainide acetate in a porcine model. Heart Rhythm 2018; 15:1882-1888. [DOI: 10.1016/j.hrthm.2018.06.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Indexed: 12/14/2022]
|
20
|
Systematic differences of non-invasive dominant frequency estimation compared to invasive dominant frequency estimation in atrial fibrillation. Comput Biol Med 2018; 104:299-309. [PMID: 30503301 PMCID: PMC6334202 DOI: 10.1016/j.compbiomed.2018.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 10/01/2018] [Accepted: 11/19/2018] [Indexed: 11/22/2022]
Abstract
Non-invasive analysis of atrial fibrillation (AF) using body surface mapping (BSM) has gained significant interest, with attempts at interpreting atrial spectro-temporal parameters from body surface signals. As these body surface signals could be affected by properties of the torso volume conductor, this interpretation is not always straightforward. This paper highlights the volume conductor effects and influences of the algorithm parameters for identifying the dominant frequency (DF) from cardiac signals collected simultaneously on the torso and atrial surface. Bi-atrial virtual electrograms (VEGMs) and BSMs were recorded simultaneously for 5 min from 10 patients undergoing ablation for persistent AF. Frequency analysis was performed on 4 s segments. DF was defined as the frequency with highest power between 4 and 10 Hz with and without applying organization index (OI) thresholds. The volume conductor effect was assessed by analyzing the highest DF (HDF) difference of each VEGM HDF against its BSM counterpart. Significant differences in HDF values between intra-cardiac and torso signals could be observed, independent of OI threshold. This difference increases with increasing endocardial HDF (BSM-VEGM median difference from -0.13 Hz for VEGM HDF at 6.25 ± 0.25 Hz to -4.24 Hz at 9.75 ± 0.25 Hz), thereby confirming the theory of the volume conductor effect in real-life situations. Applying an OI threshold strongly affected the BSM HDF area size and location and atrial HDF area location. These results suggest that volume conductor and measurement algorithm effects must be considered for appropriate clinical interpretation.
Collapse
|
21
|
Cluitmans M, Brooks DH, MacLeod R, Dössel O, Guillem MS, van Dam PM, Svehlikova J, He B, Sapp J, Wang L, Bear L. Validation and Opportunities of Electrocardiographic Imaging: From Technical Achievements to Clinical Applications. Front Physiol 2018; 9:1305. [PMID: 30294281 PMCID: PMC6158556 DOI: 10.3389/fphys.2018.01305] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 08/29/2018] [Indexed: 11/23/2022] Open
Abstract
Electrocardiographic imaging (ECGI) reconstructs the electrical activity of the heart from a dense array of body-surface electrocardiograms and a patient-specific heart-torso geometry. Depending on how it is formulated, ECGI allows the reconstruction of the activation and recovery sequence of the heart, the origin of premature beats or tachycardia, the anchors/hotspots of re-entrant arrhythmias and other electrophysiological quantities of interest. Importantly, these quantities are directly and non-invasively reconstructed in a digitized model of the patient's three-dimensional heart, which has led to clinical interest in ECGI's ability to personalize diagnosis and guide therapy. Despite considerable development over the last decades, validation of ECGI is challenging. Firstly, results depend considerably on implementation choices, which are necessary to deal with ECGI's ill-posed character. Secondly, it is challenging to obtain (invasive) ground truth data of high quality. In this review, we discuss the current status of ECGI validation as well as the major challenges remaining for complete adoption of ECGI in clinical practice. Specifically, showing clinical benefit is essential for the adoption of ECGI. Such benefit may lie in patient outcome improvement, workflow improvement, or cost reduction. Future studies should focus on these aspects to achieve broad adoption of ECGI, but only after the technical challenges have been solved for that specific application/pathology. We propose 'best' practices for technical validation and highlight collaborative efforts recently organized in this field. Continued interaction between engineers, basic scientists, and physicians remains essential to find a hybrid between technical achievements, pathological mechanisms insights, and clinical benefit, to evolve this powerful technique toward a useful role in clinical practice.
Collapse
Affiliation(s)
- Matthijs Cluitmans
- Department of Cardiology, Cardiovascular Research Institute Maastricht Maastricht University, Maastricht, Netherlands
| | - Dana H. Brooks
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, United States
| | - Rob MacLeod
- Biomedical Engineering Department, Scientific Computing and Imaging Institute (SCI), and Cardiovascular Research and Training Institute (CVRTI), The University of Utah, Salt Lake City, UT, United States
| | - Olaf Dössel
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | | | - Peter M. van Dam
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Jana Svehlikova
- Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Bin He
- Department of Biomedical Engineering Carnegie Mellon University, Pittsburgh, PA, United States
| | - John Sapp
- QEII Health Sciences Centre and Department of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Linwei Wang
- Rochester Institute of Technology, Rochester, NY, United States
| | - Laura Bear
- IHU LIRYC, Fondation Bordeaux Université, Inserm U1045 and Université de Bordeaux, Bordeaux, France
| |
Collapse
|
22
|
Hajimolahoseini H, Hashemi J, Gazor S, Redfearn D. Inflection point analysis: A machine learning approach for extraction of IEGM active intervals during atrial fibrillation. Artif Intell Med 2018; 85:7-15. [PMID: 29503040 DOI: 10.1016/j.artmed.2018.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/11/2018] [Accepted: 02/15/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVE In this paper, we propose a novel algorithm to extract the active intervals of intracardiac electrograms during atrial fibrillation. METHODS First, we show that the characteristics of the signal waveform at its inflection points are prominent features that are implicitly used by human annotators for distinguishing between active and inactive intervals of IEGMs. Then, we show that the natural logarithm of features corresponding to active and inactive intervals exhibits a mixture of two Gaussian distributions in three dimensional feature space. An Expectation Maximization algorithm for Gaussian mixtures is then applied for automatic clustering of the features into two categories. RESULTS The absolute error in onset and offset estimation of active intervals is 6.1ms and 10.7ms, respectively, guaranteeing a high resolution. The true positive rate for the proposed method is also 98.1%, proving the high reliability. CONCLUSION The proposed method can extract the active intervals of IEGMs during AF with a high accuracy and resolution close to manually annotated results. SIGNIFICANCE In contrast with some of the conventional methods, no windowing technique is required in our approach resulting in significantly higher resolution in estimating the onset and offset of active intervals. Furthermore, since the signal characteristics at inflection points are analyzed instead of signal samples, the computational time is significantly low, ensuring the real-time application of our algorithm. The proposed method is also robust to noise and baseline variations thanks to the Laplacian of Gaussian filter employed for extraction of inflection points.
Collapse
|
23
|
Feature subset selection and classification of intracardiac electrograms during atrial fibrillation. Biomed Signal Process Control 2017. [DOI: 10.1016/j.bspc.2017.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
24
|
Spectral and spatiotemporal variability ECG parameters linked to catheter ablation outcome in persistent atrial fibrillation. Comput Biol Med 2017; 88:126-131. [DOI: 10.1016/j.compbiomed.2017.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/17/2017] [Accepted: 07/03/2017] [Indexed: 11/21/2022]
|
25
|
Shariat MH, Gazor S, Redfearn DP. Bipolar Intracardiac Electrogram Active Interval Extraction During Atrial Fibrillation. IEEE Trans Biomed Eng 2017; 64:2122-2133. [DOI: 10.1109/tbme.2016.2630604] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
26
|
Sánchez C, Bueno-Orovio A, Pueyo E, Rodríguez B. Atrial Fibrillation Dynamics and Ionic Block Effects in Six Heterogeneous Human 3D Virtual Atria with Distinct Repolarization Dynamics. Front Bioeng Biotechnol 2017; 5:29. [PMID: 28534025 PMCID: PMC5420585 DOI: 10.3389/fbioe.2017.00029] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/18/2017] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) usually manifests as reentrant circuits propagating through the whole atria creating chaotic activation patterns. Little is yet known about how differences in electrophysiological and ionic properties between patients modulate reentrant patterns in AF. The goal of this study is to quantify how variability in action potential duration (APD) at different stages of repolarization determines AF dynamics and their modulation by ionic block using a set of virtual whole-atria human models. Six human whole-atria models are constructed based on the same anatomical structure and fiber orientation, but with different electrophysiological phenotypes. Membrane kinetics for each whole-atria model are selected with distinct APD characteristics at 20, 50, and 90% repolarization, from an experimentally calibrated population of human atrial action potential models, including AF remodeling and acetylcholine parasympathetic effects. Our simulations show that in all whole-atria models, reentrant circuits tend to organize around the pulmonary veins and the right atrial appendage, thus leading to higher dominant frequency (DF) and more organized activation in the left atrium than in the right atrium. Differences in APD in all phases of repolarization (not only APD90) yielded quantitative differences in fibrillation patterns with long APD associated with slower and more regular dynamics. Long APD50 and APD20 were associated with increased interatrial conduction block and interatrial differences in DF and organization index, creating reentry instability and self-termination in some cases. Specific inhibitions of IK1, INaK, or INa reduce DF and organization of the arrhythmia by enlarging wave meandering, reducing the number of secondary wavelets, and promoting interatrial block in all six virtual patients, especially for the phenotypes with short APD at 20, 50, and/or 90% repolarization. This suggests that therapies aiming at prolonging the early phase of repolarization might constitute effective antiarrhythmic strategies for the pharmacological management of AF. In summary, simulations report significant differences in atrial fibrillatory dynamics resulting from differences in APD at all phases of repolarization.
Collapse
Affiliation(s)
- Carlos Sánchez
- Biosignal Interpretation and Computational Simulation (BSICoS), I3A and IIS, University of Zaragoza, Zaragoza, Spain.,Defense University Centre (CUD), General Military Academy of Zaragoza (AGM), Zaragoza, Spain
| | | | - Esther Pueyo
- Biosignal Interpretation and Computational Simulation (BSICoS), I3A and IIS, University of Zaragoza, Zaragoza, Spain.,Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Zaragoza, Spain
| | - Blanca Rodríguez
- Department of Computer Science, University of Oxford, Oxford, UK
| |
Collapse
|
27
|
Alcaine A, Mase M, Cristoforetti A, Ravelli F, Nollo G, Laguna P, Martinez JP, Faes L. A Multi-Variate Predictability Framework to Assess Invasive Cardiac Activity and Interactions During Atrial Fibrillation. IEEE Trans Biomed Eng 2017; 64:1157-1168. [DOI: 10.1109/tbme.2016.2592953] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
28
|
Waveform Integrity in Atrial Fibrillation: The Forgotten Issue of Cardiac Electrophysiology. Ann Biomed Eng 2017; 45:1890-1907. [PMID: 28421394 DOI: 10.1007/s10439-017-1832-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 04/05/2017] [Indexed: 01/17/2023]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in clinical practice with an increasing prevalence of about 15% in the elderly. Despite other alternatives, catheter ablation is currently considered as the first-line therapy for the treatment of AF. This strategy relies on cardiac electrophysiology systems, which use intracardiac electrograms (EGM) as the basis to determine the cardiac structures contributing to sustain the arrhythmia. However, the noise-free acquisition of these recordings is impossible and they are often contaminated by different perturbations. Although suppression of nuisance signals without affecting the original EGM pattern is essential for any other later analysis, not much attention has been paid to this issue, being frequently considered as trivial. The present work introduces the first thorough study on the significant fallout that regular filtering, aimed at reducing acquisition noise, provokes on EGM pattern morphology. This approach has been compared with more refined denoising strategies. Performance has been assessed both in time and frequency by well established parameters for EGM characterization. The study comprised synthesized and real EGMs with unipolar and bipolar recordings. Results reported that regular filtering altered substantially atrial waveform morphology and was unable to remove moderate amounts of noise, thus turning time and spectral characterization of the EGM notably inaccurate. Methods based on Wavelet transform provided the highest ability to preserve EGM morphology with improvements between 20 and beyond 40%, to minimize dominant atrial frequency estimation error with up to 25% reduction, as well as to reduce huge levels of noise with up to 10 dB better reduction. Consequently, these algorithms are recommended as a replacement of regular filtering to avoid significant alterations in the EGMs. This could lead to more accurate and truthful analyses of atrial activity dynamics aimed at understanding and locating the sources of AF.
Collapse
|
29
|
Li X, Salinet JL, Almeida TP, Vanheusden FJ, Chu GS, Ng GA, Schlindwein FS. An interactive platform to guide catheter ablation in human persistent atrial fibrillation using dominant frequency, organization and phase mapping. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2017; 141:83-92. [PMID: 28241971 DOI: 10.1016/j.cmpb.2017.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/05/2017] [Accepted: 01/17/2017] [Indexed: 06/06/2023]
Abstract
BACKGROUND AND OBJECTIVE Optimal targets for persistent atrial fibrillation (persAF) ablation are still debated. Atrial regions hosting high dominant frequency (HDF) are believed to participate in the initiation and maintenance of persAF and hence are potential targets for ablation, while rotor ablation has shown promising initial results. Currently, no commercially available system offers the capability to automatically identify both these phenomena. This paper describes an integrated 3D software platform combining the mapping of both frequency spectrum and phase from atrial electrograms (AEGs) to help guide persAF ablation in clinical cardiac electrophysiological studies. METHODS 30s of 2048 non-contact AEGs (EnSite Array, St. Jude Medical) were collected and analyzed per patient. After QRST removal, the AEGs were divided into 4s windows with a 50% overlap. Fast Fourier transform was used for DF identification. HDF areas were identified as the maximum DF to 0.25Hz below that, and their centers of gravity (CGs) were used to track their spatiotemporal movement. Spectral organization measurements were estimated. Hilbert transform was used to calculate instantaneous phase. RESULTS The system was successfully used to guide catheter ablation for 10 persAF patients. The mean processing time was 10.4 ± 1.5min, which is adequate comparing to the normal electrophysiological (EP) procedure time (120∼180min). CONCLUSIONS A customized software platform capable of measuring different forms of spatiotemporal AEG analysis was implemented and used in clinical environment to guide persAF ablation. The modular nature of the platform will help electrophysiological studies in understanding of the underlying AF mechanisms.
Collapse
Affiliation(s)
- Xin Li
- Department of Engineering, University of Leicester, UK; Department of Cardiovascular Science, University of Leicester, UK
| | - João L Salinet
- Biomedical Engineering, Center for Engineering, Modelling and Applied Social Sciences, Universidade Federal do ABC, Brazil; Bioengineering Division, Heart Institute (InCor), Brasil
| | - Tiago P Almeida
- Department of Engineering, University of Leicester, UK; Biomedical Engineering, Center for Engineering, Modelling and Applied Social Sciences, Universidade Federal do ABC, Brazil
| | | | - Gavin S Chu
- Department of Cardiovascular Science, University of Leicester, UK; University Hospitals of Leicester NHS Trust, UK
| | - G André Ng
- Department of Cardiovascular Science, University of Leicester, UK; University Hospitals of Leicester NHS Trust, UK; National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, UK
| | - Fernando S Schlindwein
- Department of Engineering, University of Leicester, UK; National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Glenfield Hospital, UK.
| |
Collapse
|
30
|
Electrocardiographic Spectral Features for Long-Term Outcome Prognosis of Atrial Fibrillation Catheter Ablation. Ann Biomed Eng 2016; 44:3307-3318. [PMID: 27221509 DOI: 10.1007/s10439-016-1641-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/04/2016] [Indexed: 10/21/2022]
Abstract
Atrial fibrillation (AF) is the most common arrhythmia in routine clinical practice. Despite many years of research, its mechanisms still are not well understood, thus reducing the effectiveness of AF treatments. Nowadays, pulmonary vein isolation by catheter ablation is the treatment of choice for AF resistant either to pharmacological or electrical cardioversion. However, given that long-term recurrences are common, an appropriate patient selection before the procedure is of paramount relevance in the improvement of AF catheter ablation outcome. The present work studies how several spectral features of the atrial activity (AA) from a single lead of the surface electrocardiogram (ECG) can become potential pre-ablation predictors of long-term (>2 months) sinus rhythm maintenance. Among all the analyzed spectral features, results indicated that the most significant single predictor of paroxysmal AF ablation treatment outcome was related to the amplitude of the first harmonic of the dominant frequency, providing sensitivity (Se), specificity (Sp) and accuracy (Ac) values of 90%, 42.86 and 77.78%, respectively. On the other hand, the AA harmonic structure was the most significant single predictor for persistent AF, with Se, Sp and Ac values of 100%, 54.55 and 77.27%, respectively. A logistic regression analysis, mainly based on spectral amplitudes as well as on the harmonic structure of the AA, provided a higher predictive ability both for paroxysmal AF (Se = 100%, Sp = 57.14% and Ac = 88.89%) and persistent AF (Se = 90.91%, Sp = 72.73 and Ac = 81.82%). In conclusion, the study of key AA spectral features from the surface ECG can provide a significant preoperative prognosis of AF catheter ablation outcome at long-term follow-up.
Collapse
|
31
|
Li W, Yang C, Wang Y, Wang D, Chen Y, Wu Z. Several insights into the preprocessing of electrograms in atrial fibrillation for dominant frequency analysis. Biomed Eng Online 2016; 15:38. [PMID: 27067549 PMCID: PMC4828784 DOI: 10.1186/s12938-016-0157-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/04/2016] [Indexed: 02/05/2023] Open
Abstract
Background Dominant frequency (DF) analysis of atrial electrograms has become an important method in characterizing atrial fibrillation (AF). As a classic method, Botteron’s approach is widely used in the preprocessing of frequency analysis during AF. It includes three steps: (1) band-pass filtering at 40–250 Hz, (2) absolute value, and (3) low-pass filtering at 20 Hz. This paper aims to expound the necessity and adjustability of each step. Methods and results Unipolar epicardial mapping signals were recorded during AF from eight mongrel dogs with cholinergic AF model. Episodes of these data were randomly selected to evaluate the impact of different pass bands and the necessity of low-pass filtering with 20 Hz cutoff frequency. Each episode of AF signal is 5 s long with a sampling rate of 2 kHz. Simulated electrograms were adopted to discuss the role of taking absolute value. Furthermore, direct spectral analysis method (FFT et al.) is compared with Botteron’s preprocessing approach. According to our statistical analysis, the pass band of 40–250 Hz was not the best, while 20–100 Hz presented the high accuracy rate of DF. From the comparing result of direct FFT without Botteron’s approach we deduced that the rectification of absolute value was meaningful for the fundamental atrial frequency. The final step, 20 Hz low-pass filter can completely be omitted in DF analysis. In consideration of the demand for real-time distribution of DF in clinical or experimental situations, down-sampling method and the impact of ventricular artifacts on DF was also discussed. Conclusion In the actual application of the three preprocessing steps, the pass band selection of band-pass filter can be adjusted and the rectification of taking absolute value is important. Nevertheless, the final step of 20 Hz low-pass filter is totally unnecessary. In real-time signal processing situations, taking down-sampling method and ignoring the ventricular artifacts can also have high performance in DF analysis of atrial electrograms.
Collapse
Affiliation(s)
- Wenhai Li
- Department of Electronic Engineering, Fudan University, Shanghai, 200433, China
| | - Cuiwei Yang
- Department of Electronic Engineering, Fudan University, Shanghai, 200433, China. .,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, 200433, China. .,Shanghai Engineering Research Center of Assistive Devices, Shanghai, 200433, China.
| | - Yanlei Wang
- Department of Electronic Engineering, Fudan University, Shanghai, 200433, China
| | - Dexi Wang
- Department of Electronic Engineering, Fudan University, Shanghai, 200433, China
| | - Ying Chen
- Department of Electronic Science and Engineering, Nanjing University, Nanjing, 210046, Jiangsu, China
| | - Zhong Wu
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
| |
Collapse
|
32
|
Orozco-Duque A, Novak D, Kremen V, Bustamante J. Multifractal analysis for grading complex fractionated electrograms in atrial fibrillation. Physiol Meas 2015; 36:2269-84. [DOI: 10.1088/0967-3334/36/11/2269] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
33
|
Ullah W, Hunter RJ, Baker V, Ling LH, Dhinoja MB, Sporton S, Earley MJ, Schilling RJ. Impact of Catheter Contact Force on Human Left Atrial Electrogram Characteristics in Sinus Rhythm and Atrial Fibrillation. Circ Arrhythm Electrophysiol 2015; 8:1030-9. [DOI: 10.1161/circep.114.002483] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 06/26/2015] [Indexed: 11/16/2022]
Affiliation(s)
- Waqas Ullah
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| | - Ross J. Hunter
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| | - Victoria Baker
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| | - Liang-Han Ling
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| | - Mehul B. Dhinoja
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| | - Simon Sporton
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| | - Mark J. Earley
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| | - Richard J. Schilling
- From the Cardiovascular Biomedical Research Unit, St. Bartholomew’s Hospital, Barts Health NHS Trust, London, United Kingdom (W.U., R.J.H., V.B., M.B.D., S.S., M.J.E., R.J.S.); and Department of Cardiovascular Medicine, Alfred Hospital and Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (L.-H.L.)
| |
Collapse
|
34
|
Julián M, Alcaraz R, Rieta JJ. Application of Hurst exponents to assess atrial reverse remodeling in paroxysmal atrial fibrillation. Physiol Meas 2015; 36:2231-46. [DOI: 10.1088/0967-3334/36/11/2231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|
35
|
Developing a New Computer-Aided Clinical Decision Support System for Prediction of Successful Postcardioversion Patients with Persistent Atrial Fibrillation. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:527815. [PMID: 26120354 PMCID: PMC4450306 DOI: 10.1155/2015/527815] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 02/12/2015] [Accepted: 02/17/2015] [Indexed: 11/17/2022]
Abstract
We propose a new algorithm to predict the outcome of direct-current electric (DCE) cardioversion for atrial fibrillation (AF) patients. AF is the most common cardiac arrhythmia and DCE cardioversion is a noninvasive treatment to end AF and return the patient to sinus rhythm (SR). Unfortunately, there is a high risk of AF recurrence in persistent AF patients; hence clinically it is important to predict the DCE outcome in order to avoid the procedure's side effects. This study develops a feature extraction and classification framework to predict AF recurrence patients from the underlying structure of atrial activity (AA). A multiresolution signal decomposition technique, based on matching pursuit (MP), was used to project the AA over a dictionary of wavelets. Seven novel features were derived from the decompositions and were employed in a quadratic discrimination analysis classification to predict the success of post-DCE cardioversion in 40 patients with persistent AF. The proposed algorithm achieved 100% sensitivity and 95% specificity, indicating that the proposed computational approach captures detailed structural information about the underlying AA and could provide reliable information for effective management of AF.
Collapse
|
36
|
Everett TH, Hulley GS, Lee KW, Chang R, Wilson EE, Olgin JE. The effects of remodeling with heart failure on mode of initiation of ventricular fibrillation and its spatiotemporal organization. J Interv Card Electrophysiol 2015; 43:205-15. [PMID: 26001644 DOI: 10.1007/s10840-015-0016-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/05/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE The effect of the heart failure substrate on the initiation of ventricular fibrillation (VF) and its resulting mechanism is not known. The objective of this study was to determine the effects of substrate on VF initiation and its spatiotemporal organization in the heart failure model. METHODS Optical action potentials were recorded from LV wedge preparations either from structurally normal hearts (control, n = 11) or from congestive heart failure (CHF; n = 7), at the epicardial surface, endocardial surface which included a papillary muscle, and a transmural cross section. Action potential duration (APD(80)) was determined, and VF was initiated. A fast Fourier transform was calculated, and the dominant frequency (DF) was determined. RESULTS The CHF group showed increased VF vulnerability (69 vs 26 %, p < 0.03), and every mapped surface showed an APD(80) gradient which included islands of higher APDs on the transmural surface (M cells) which was not observed in controls. VF in the CHF group was characterized by stable, discrete, high-DF areas that correlated to either foci or spiral waves located on the transmural surface at the site of the papillary muscle. Overall, the top 10 % of DFs correlated to an APD of 101 ms while the bottom 10 % of DFs correlated to an APD of 126 ms (p < 0.01). CONCLUSIONS In the CHF model, APD gradients correlated with an increased vulnerability to VF, and the highest stable DFs were located on the transmural surface which was not seen in controls. This indicates that the CHF substrate creates unique APD and DF characteristics.
Collapse
Affiliation(s)
- Thomas H Everett
- Krannert Institute of Cardiology, Indiana University School of Medicine, 1800 N. Capitol, Ste. E400E, Indianapolis, IN, 46202, USA,
| | | | | | | | | | | |
Collapse
|
37
|
Letsas KP, Efremidis M, Sgouros NP, Vlachos K, Asvestas D, Sideris A. Catheter ablation of persistent atrial fibrillation: The importance of substrate modification. World J Cardiol 2015; 7:111-118. [PMID: 25810810 PMCID: PMC4365304 DOI: 10.4330/wjc.v7.i3.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 12/26/2014] [Accepted: 01/20/2015] [Indexed: 02/06/2023] Open
Abstract
Accumulating data have shown that elimination of atrial fibrillation (AF) sources should be the goal in persistent AF ablation. Pulmonary vein isolation, linear lesions and complex fractionated atrial electrograms (CFAEs) ablation have shown limited efficacy in patients with persistent AF. A combined approach using voltage, CFAEs and dominant frequency (DF) mapping may be helpful for the identification of AF sources and subsequent focal substrate modification. The fibrillatory activity is maintained by intramural reentry centered on fibrotic patches. Voltage mapping may assist in the identification of fibrotic areas. Stable rotors display the higher DF and possibly drive AF. Furthermore, the single rotor is usually consistent with organized AF electrograms without fractionation. It is therefore quite possible that rotors are located at relatively “healthy islands” within the patchy fibrosis. This is supported by the fact that high DF sites have been negatively correlated to the amount of fibrosis. CFAEs are located in areas adjacent to high DF. In conclusion, patchy fibrotic areas displaying the maximum DF along with high organization index and the lower fractionation index are potential targets of ablation. Prospective studies are required to validate the efficacy of substrate modification in left atrial ablation outcomes.
Collapse
|
38
|
VERRIER RICHARDL, SILVA ANAF, BONATTI RODOLFO, BATATINHA JULIOA, NEARING BRUCED, LIU GONGXIN, RAJAMANI SRIDHARAN, ZENG DEWAN, BELARDINELLI LUIZ. Combined Actions of Ivabradine and Ranolazine Reduce Ventricular Rate During Atrial Fibrillation. J Cardiovasc Electrophysiol 2014; 26:329-35. [DOI: 10.1111/jce.12569] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/15/2014] [Accepted: 10/16/2014] [Indexed: 01/09/2023]
Affiliation(s)
- RICHARD L. VERRIER
- Department of Medicine; Beth Israel Deaconess Medical Center
- Harvard Medical School; Boston Massachusetts USA
| | - ANA F.G. SILVA
- Department of Medicine; Beth Israel Deaconess Medical Center
- Faculdade de Medicina de Universidade de São Paulo; São Paulo Brazil
| | - RODOLFO BONATTI
- Department of Medicine; Beth Israel Deaconess Medical Center
- Faculdade de Medicina de Universidade de São Paulo; São Paulo Brazil
| | - JULIO A.P. BATATINHA
- Department of Medicine; Beth Israel Deaconess Medical Center
- Faculdade de Medicina de Universidade de São Paulo; São Paulo Brazil
| | - BRUCE D. NEARING
- Department of Medicine; Beth Israel Deaconess Medical Center
- Harvard Medical School; Boston Massachusetts USA
| | - GONGXIN LIU
- Gilead Sciences; Inc; Foster City California USA
| | | | - DEWAN ZENG
- Gilead Sciences; Inc; Foster City California USA
| | | |
Collapse
|
39
|
Verrier RL, Bonatti R, Silva AF, Batatinha JA, Nearing BD, Liu G, Rajamani S, Zeng D, Belardinelli L. If inhibition in the atrioventricular node by ivabradine causes rate-dependent slowing of conduction and reduces ventricular rate during atrial fibrillation. Heart Rhythm 2014; 11:2288-96. [DOI: 10.1016/j.hrthm.2014.08.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Indexed: 01/09/2023]
|
40
|
Ravelli F, Masè M, Cristoforetti A, Marini M, Disertori M. The logical operator map identifies novel candidate markers for critical sites in patients with atrial fibrillation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:186-97. [PMID: 25077410 DOI: 10.1016/j.pbiomolbio.2014.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 07/17/2014] [Indexed: 11/28/2022]
Abstract
The identification of suitable markers for critical patterns during atrial fibrillation (AF) may be crucial to guide an effective ablation treatment. Single parameter maps, based on dominant frequency and complex fractionated electrograms, have been proposed as a tool for electrogram-guided ablation, however the specificity of these markers is debated. Experimental studies suggest that AF critical patterns may be identified on the basis of specific rate and organization features, where rapid organized and rapid fragmented activities characterize respectively localized sources and critical substrates. In this paper we introduce the logical operator map, a novel mapping tool for a point-by-point identification and localization of AF critical sites. Based on advanced signal and image processing techniques, the approach combines in a single map electrogram-derived rate and organization features with tomographic anatomical detail. The construction of the anatomically-detailed logical operator map is based on the time-domain estimation of atrial rate and organization in terms of cycle length and wave-similarity, the logical combination of these indexes to obtain suitable markers of critical sites, and the multimodal integration of electrophysiological and anatomical information by segmentation and registration techniques. Logical operator maps were constructed in 14 patients with persistent AF, showing the capability of the combined rate and organization markers to identify with high selectivity the subset of electrograms associated with localized sources and critical substrates. The precise anatomical localization of these critical sites revealed the confinement of rapid organized sources in the left atrium with organization and rate gradients towards the surrounding tissue, and the presence of rapid fragmented electrograms in proximity of the sources. By merging in a single map the most relevant electrophysiological and anatomical features of the AF process, the logical operator map may have significant clinical impact as a direct, comprehensive tool to understand arrhythmia mechanisms in the single patient and guide more conservative, step-wise ablation.
Collapse
Affiliation(s)
- Flavia Ravelli
- Department of Physics, University of Trento, Povo-Trento, Italy.
| | - Michela Masè
- Department of Physics, University of Trento, Povo-Trento, Italy
| | | | | | - Marcello Disertori
- Division of Cardiology, S. Chiara Hospital, Trento, Italy; Healthcare Research and Innovation Program, PAT-FBK, Trento, Italy
| |
Collapse
|
41
|
Trayanova NA. Mathematical approaches to understanding and imaging atrial fibrillation: significance for mechanisms and management. Circ Res 2014; 114:1516-31. [PMID: 24763468 DOI: 10.1161/circresaha.114.302240] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is the most common sustained arrhythmia in humans. The mechanisms that govern AF initiation and persistence are highly complex, of dynamic nature, and involve interactions across multiple temporal and spatial scales in the atria. This article aims to review the mathematical modeling and computer simulation approaches to understanding AF mechanisms and aiding in its management. Various atrial modeling approaches are presented, with descriptions of the methodological basis and advancements in both lower-dimensional and realistic geometry models. A review of the most significant mechanistic insights made by atrial simulations is provided. The article showcases the contributions that atrial modeling and simulation have made not only to our understanding of the pathophysiology of atrial arrhythmias, but also to the development of AF management approaches. A summary of the future developments envisioned for the field of atrial simulation and modeling is also presented. The review contends that computational models of the atria assembled with data from clinical imaging modalities that incorporate electrophysiological and structural remodeling could become a first line of screening for new AF therapies and approaches, new diagnostic developments, and new methods for arrhythmia prevention.
Collapse
Affiliation(s)
- Natalia A Trayanova
- From the Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD
| |
Collapse
|
42
|
Hernández A, Alcaraz R, Hornero F, Rieta JJ. Preoperative study of the surface ECG for the prognosis of atrial fibrillation maze surgery outcome at discharge. Physiol Meas 2014; 35:1409-23. [PMID: 24875277 DOI: 10.1088/0967-3334/35/7/1409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Cox-maze surgery is an effective procedure for terminating atrial fibrillation (AF) in patients requiring open-heart surgery associated with another heart disease. After the intervention, regardless of the patient's rhythm, all are treated with oral anticoagulants and antiarrhythmic drugs prior to discharge. Furthermore, patients maintaining AF before discharge could also be treated with electrical cardioversion (ECV). In view of this, a preoperative prognosis of the patient's rhythm at discharge would be helpful for optimizing drug therapy planning as well as for advancing ECV therapy. This work analyzes 30 preoperative electrocardiograms (ECGs) from patients suffering from AF in order to predict the Cox-maze surgery outcome at discharge. Two different characteristics of the AF pattern have been studied. On the one hand, the atrial activity (AA) organization, which provides information about the number of propagating wavelets in the atria, was investigated. AA organization has been successfully used in previous studies related to spontaneous reversion of paroxysmal AF and to the outcome of ECV. To assess organization, the dominant atrial frequency (DAF) and sample entropy (SampEn) have been computed. On the other hand, the second characteristic studied was the fibrillatory wave (f-wave) amplitude, which has been demonstrated to be a valuable indicator of the Cox-maze surgery outcome in previous studies. Moreover, this parameter has been obtained through a new methodology, based on computing the f-wave average power (fWP). Finally, all the computed indices were combined in a decision tree in order to improve prediction capability. Results for the DAF yielded a sensitivity (Se), a specificity (Sp) and an accuracy (Acc) of 61.54%, 82.35% and 73.33%, respectively. For SampEn the values were 69.23%, 76.00% and 73.33%, respectively, and for fWP they were 92.31%, 82.35% and 86.67%, respectively. Finally, the decision tree combining the three parameters analyzed improved the preoperative prognosis of the Cox-maze outcome with values of Se, Sp and Acc of 100%, 82.35% and 90%, respectively. As a consequence, the analysis of parameters related to the f-wave pattern, extracted from the preoperative ECG, has provided a considerable ability to predict the outcome of AF Cox-maze surgery at discharge.
Collapse
Affiliation(s)
- Antonio Hernández
- Biomedical Synergy, Electronic Engineering Department, Universidad Politécnica de Valencia, Valencia, Spain
| | | | | | | |
Collapse
|
43
|
Ravelli F, Masè M. Computational mapping in atrial fibrillation: how the integration of signal-derived maps may guide the localization of critical sources. ACTA ACUST UNITED AC 2014; 16:714-23. [DOI: 10.1093/europace/eut376] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
44
|
Gerstenfeld EP, Everett TH. Internal Atrial Defibrillation Revisited. J Am Coll Cardiol 2014; 63:49-51. [DOI: 10.1016/j.jacc.2013.06.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 06/13/2013] [Indexed: 11/16/2022]
|
45
|
CASTELLS FRANCISCO, CERVIGÓN RAQUEL, MILLET JOSÉ. On the Preprocessing of Atrial Electrograms in Atrial Fibrillation: Understanding Botteron's Approach. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2013; 37:133-43. [DOI: 10.1111/pace.12288] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 07/20/2013] [Accepted: 08/14/2013] [Indexed: 11/29/2022]
Affiliation(s)
| | - RAQUEL CERVIGÓN
- Escuela Politécnica de Cuenca; Universidad de Castilla la Mancha; Cuenca Spain
| | - JOSÉ MILLET
- ITACA Institute; Universitat Politècnica de València; València Spain
| |
Collapse
|
46
|
Requena-Carrión J, Alonso-Atienza F, Everss E, Sánchez-Muñoz JJ, Ortiz M, García-Alberola A, Rojo-Álvarez JL. Analysis of the robustness of spectral indices during ventricular fibrillation. Biomed Signal Process Control 2013. [DOI: 10.1016/j.bspc.2013.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
47
|
Inhibition of If in the atrioventricular node as a mechanism for dronedarone’s reduction in ventricular rate during atrial fibrillation. Heart Rhythm 2013; 10:1692-7. [DOI: 10.1016/j.hrthm.2013.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Indexed: 01/09/2023]
|
48
|
Requena-Carrión J, Beltrán-Molina FA, Marques AG. Relating the spectrum of cardiac signals to the spatiotemporal dynamics of cardiac sources. Biomed Signal Process Control 2013. [DOI: 10.1016/j.bspc.2013.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
49
|
Nonlinear synchronization assessment between atrial and ventricular activations series from the surface ECG in atrial fibrillation. Biomed Signal Process Control 2013. [DOI: 10.1016/j.bspc.2013.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
50
|
Sun L, Wang Y, Yang C, Chen Y, Wu Z, Yu J. Evaluating epicardial mapping electrogram by the method of dominant frequency and Lorenz plot. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:1021-4. [PMID: 24109864 DOI: 10.1109/embc.2013.6609677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The methods of dominant frequency and Lorenz plot are used in this study to evaluate the activation rate and the activation rate variability of cardiac signals during atrial fibrillation. An epicardial mapping system was applied to acquire the atrial electrogram of mongrel dogs. The dominant frequency and Lorenz plot of each signal from various myocardial regions of the atria were analyzed. Our results show that both a frequency gradient and a variability gradient exist in the atria and the roots of pulmonary veins. The dominant frequencies of the anterior atria are higher than the posterior ones and the activation variability of both atria was higher than those of the pulmonary veins. A combination of these two methods may provide a more comprehensive understanding of the electrophysiology mechanism associated with atrial fibrillation.
Collapse
|