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Marcotte CD, Hoffman MJ, Fenton FH, Cherry EM. Reconstructing cardiac electrical excitations from optical mapping recordings. CHAOS (WOODBURY, N.Y.) 2023; 33:093141. [PMID: 37756611 PMCID: PMC10539031 DOI: 10.1063/5.0156314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023]
Abstract
The reconstruction of electrical excitation patterns through the unobserved depth of the tissue is essential to realizing the potential of computational models in cardiac medicine. We have utilized experimental optical-mapping recordings of cardiac electrical excitation on the epicardial and endocardial surfaces of a canine ventricle as observations directing a local ensemble transform Kalman filter data assimilation scheme. We demonstrate that the inclusion of explicit information about the stimulation protocol can marginally improve the confidence of the ensemble reconstruction and the reliability of the assimilation over time. Likewise, we consider the efficacy of stochastic modeling additions to the assimilation scheme in the context of experimentally derived observation sets. Approximation error is addressed at both the observation and modeling stages through the uncertainty of observations and the specification of the model used in the assimilation ensemble. We find that perturbative modifications to the observations have marginal to deleterious effects on the accuracy and robustness of the state reconstruction. Furthermore, we find that incorporating additional information from the observations into the model itself (in the case of stimulus and stochastic currents) has a marginal improvement on the reconstruction accuracy over a fully autonomous model, while complicating the model itself and thus introducing potential for new types of model errors. That the inclusion of explicit modeling information has negligible to negative effects on the reconstruction implies the need for new avenues for optimization of data assimilation schemes applied to cardiac electrical excitation.
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Affiliation(s)
- C. D. Marcotte
- Department of Computer Science, Durham University, Durham DH1 3LE, United Kingdom
| | - M. J. Hoffman
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - F. H. Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - E. M. Cherry
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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2
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Stenger R, Herzog S, Kottlarz I, Rüchardt B, Luther S, Wörgötter F, Parlitz U. Reconstructing in-depth activity for chaotic 3D spatiotemporal excitable media models based on surface data. CHAOS (WOODBURY, N.Y.) 2023; 33:013134. [PMID: 36725654 DOI: 10.1063/5.0126824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
Motivated by potential applications in cardiac research, we consider the task of reconstructing the dynamics within a spatiotemporal chaotic 3D excitable medium from partial observations at the surface. Three artificial neural network methods (a spatiotemporal convolutional long-short-term-memory, an autoencoder, and a diffusion model based on the U-Net architecture) are trained to predict the dynamics in deeper layers of a cube from observational data at the surface using data generated by the Barkley model on a 3D domain. The results show that despite the high-dimensional chaotic dynamics of this system, such cross-prediction is possible, but non-trivial and as expected, its quality decreases with increasing prediction depth.
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Affiliation(s)
- R Stenger
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
| | - S Herzog
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
| | - I Kottlarz
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
| | - B Rüchardt
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
| | - S Luther
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
| | - F Wörgötter
- Department for Computational Neuroscience, Third Institute of Physics-Biophysics, University of Göttingen, 37077 Göttingen, Germany
| | - U Parlitz
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
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Lebert J, Mittal M, Christoph J. Reconstruction of three-dimensional scroll waves in excitable media from two-dimensional observations using deep neural networks. Phys Rev E 2023; 107:014221. [PMID: 36797900 DOI: 10.1103/physreve.107.014221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/17/2023] [Indexed: 02/03/2023]
Abstract
Scroll wave dynamics are thought to underlie life-threatening ventricular fibrillation. However, direct observations of three-dimensional electrical scroll waves remain elusive, as there is no direct way to measure action potential wave patterns transmurally throughout the thick ventricular heart muscle. Here we study whether it is possible to reconstruct simulated scroll waves and scroll wave chaos using deep learning. We trained encoding-decoding convolutional neural networks to predict three-dimensional scroll wave dynamics inside bulk-shaped excitable media from two-dimensional observations of the wave dynamics on the bulk's surface. We tested whether observations from one or two opposing surfaces would be sufficient and whether transparency or measurements of surface deformations enhances the reconstruction. Further, we evaluated the approach's robustness against noise and tested the feasibility of predicting the bulk's thickness. We distinguished isotropic and anisotropic, as well as opaque and transparent, excitable media as models for cardiac tissue and the Belousov-Zhabotinsky chemical reaction, respectively. While we demonstrate that it is possible to reconstruct three-dimensional scroll wave dynamics, we also show that it is challenging to reconstruct complicated scroll wave chaos and that prediction outcomes depend on various factors such as transparency, anisotropy, and ultimately the thickness of the medium compared to the size of the scroll waves. In particular, we found that anisotropy provides crucial information for neural networks to decode depth, which facilitates the reconstructions. In the future, deep neural networks could be used to visualize intramural action potential wave patterns from epi- or endocardial measurements.
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Affiliation(s)
- Jan Lebert
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California 94158, USA
| | - Meenakshi Mittal
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California 94158, USA
- Department of Computer Science, University of California, Berkeley, Berkeley, California 94720, USA
| | - Jan Christoph
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California 94158, USA
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Herrero Martin C, Oved A, Chowdhury RA, Ullmann E, Peters NS, Bharath AA, Varela M. EP-PINNs: Cardiac Electrophysiology Characterisation Using Physics-Informed Neural Networks. Front Cardiovasc Med 2022; 8:768419. [PMID: 35187101 PMCID: PMC8850959 DOI: 10.3389/fcvm.2021.768419] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022] Open
Abstract
Accurately inferring underlying electrophysiological (EP) tissue properties from action potential recordings is expected to be clinically useful in the diagnosis and treatment of arrhythmias such as atrial fibrillation. It is, however, notoriously difficult to perform. We present EP-PINNs (Physics Informed Neural Networks), a novel tool for accurate action potential simulation and EP parameter estimation from sparse amounts of EP data. We demonstrate, using 1D and 2D in silico data, how EP-PINNs are able to reconstruct the spatio-temporal evolution of action potentials, whilst predicting parameters related to action potential duration (APD), excitability and diffusion coefficients. EP-PINNs are additionally able to identify heterogeneities in EP properties, making them potentially useful for the detection of fibrosis and other localised pathology linked to arrhythmias. Finally, we show EP-PINNs effectiveness on biological in vitro preparations, by characterising the effect of anti-arrhythmic drugs on APD using optical mapping data. EP-PINNs are a promising clinical tool for the characterisation and potential treatment guidance of arrhythmias.
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Affiliation(s)
- Clara Herrero Martin
- Department of Bioengineering, Imperial College London, London, United Kingdom
- ITACA Institute, Universitat Politècnica de València, Valencia, Spain
| | - Alon Oved
- Department of Computing, Imperial College London, London, United Kingdom
| | - Rasheda A. Chowdhury
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Elisabeth Ullmann
- Department of Mathematics, Technical University of Munich, Munich, Germany
| | - Nicholas S. Peters
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Anil A. Bharath
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Marta Varela
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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Shahi S, Marcotte CD, Herndon CJ, Fenton FH, Shiferaw Y, Cherry EM. Long-Time Prediction of Arrhythmic Cardiac Action Potentials Using Recurrent Neural Networks and Reservoir Computing. Front Physiol 2021; 12:734178. [PMID: 34646159 PMCID: PMC8502981 DOI: 10.3389/fphys.2021.734178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/27/2021] [Indexed: 11/13/2022] Open
Abstract
The electrical signals triggering the heart's contraction are governed by non-linear processes that can produce complex irregular activity, especially during or preceding the onset of cardiac arrhythmias. Forecasts of cardiac voltage time series in such conditions could allow new opportunities for intervention and control but would require efficient computation of highly accurate predictions. Although machine-learning (ML) approaches hold promise for delivering such results, non-linear time-series forecasting poses significant challenges. In this manuscript, we study the performance of two recurrent neural network (RNN) approaches along with echo state networks (ESNs) from the reservoir computing (RC) paradigm in predicting cardiac voltage data in terms of accuracy, efficiency, and robustness. We show that these ML time-series prediction methods can forecast synthetic and experimental cardiac action potentials for at least 15–20 beats with a high degree of accuracy, with ESNs typically two orders of magnitude faster than RNN approaches for the same network size.
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Affiliation(s)
- Shahrokh Shahi
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Christopher D Marcotte
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Conner J Herndon
- School of Physics, Georgia Institute of Technology, Atlanta, GA, United States
| | - Flavio H Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, GA, United States
| | - Yohannes Shiferaw
- Department of Physics & Astronomy, California State University, Northridge, CA, United States
| | - Elizabeth M Cherry
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, United States
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Marcotte CD, Fenton FH, Hoffman MJ, Cherry EM. Robust data assimilation with noise: Applications to cardiac dynamics. CHAOS (WOODBURY, N.Y.) 2021; 31:013118. [PMID: 33754752 PMCID: PMC7796825 DOI: 10.1063/5.0033539] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 05/05/2023]
Abstract
Reconstructions of excitation patterns in cardiac tissue must contend with uncertainties due to model error, observation error, and hidden state variables. The accuracy of these state reconstructions may be improved by efforts to account for each of these sources of uncertainty, in particular, through the incorporation of uncertainty in model specification and model dynamics. To this end, we introduce stochastic modeling methods in the context of ensemble-based data assimilation and state reconstruction for cardiac dynamics in one- and three-dimensional cardiac systems. We propose two classes of methods, one following the canonical stochastic differential equation formalism, and another perturbing the ensemble evolution in the parameter space of the model, which are further characterized according to the details of the models used in the ensemble. The stochastic methods are applied to a simple model of cardiac dynamics with fast-slow time-scale separation, which permits tuning the form of effective stochastic assimilation schemes based on a similar separation of dynamical time scales. We find that the selection of slow or fast time scales in the formulation of stochastic forcing terms can be understood analogously to existing ensemble inflation techniques for accounting for finite-size effects in ensemble Kalman filter methods; however, like existing inflation methods, care must be taken in choosing relevant parameters to avoid over-driving the data assimilation process. In particular, we find that a combination of stochastic processes-analogously to the combination of additive and multiplicative inflation methods-yields improvements to the assimilation error and ensemble spread over these classical methods.
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Affiliation(s)
- Christopher D. Marcotte
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Flavio H. Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Matthew J. Hoffman
- School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623, USA
| | - Elizabeth M. Cherry
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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Mirams GR, Niederer SA, Clayton RH. The fickle heart: uncertainty quantification in cardiac and cardiovascular modelling and simulation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20200119. [PMID: 32448073 PMCID: PMC7287327 DOI: 10.1098/rsta.2020.0119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- Gary R. Mirams
- School of Mathematical Sciences, University of Nottingham, Mathematical Sciences Building, University Park, Nottingham, Nottinghamshire NG7 2RD, UK
- e-mail:
| | - Steven A. Niederer
- Division of Imaging Sciences and Biomedical Engineering, Kings College London, The Rayne Institute, 4th Floor, Lambeth Wing, St Thomas’ Hospital, London SE1 7EH, UK
| | - Richard H. Clayton
- Computer Science, University of Sheffield, Regent Court, 211 Portobello, Sheffield S1 4DP, UK
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