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Amrutha SV, Sebastian A, Sibeesh P, Punacha S, Shajahan TK. Theory and experiments of spiral unpinning in the Belousov-Zhabotinsky reaction using a circularly polarized electric field. CHAOS (WOODBURY, N.Y.) 2023; 33:063157. [PMID: 37368041 DOI: 10.1063/5.0145251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 06/05/2023] [Indexed: 06/28/2023]
Abstract
We present the first experimental study of unpinning an excitation wave using a circularly polarized electric field. The experiments are conducted using the excitable chemical medium, the Belousov-Zhabotinsky (BZ) reaction, which is modeled with the Oregenator model. The excitation wave in the chemical medium is charged so that it can directly interact with the electric field. This is a unique feature of the chemical excitation wave. The mechanism of wave unpinning in the BZ reaction with a circularly polarized electric field is investigated by varying the pacing ratio, the initial phase of the wave, and field strength. The chemical wave in the BZ reaction unpins when the electric force opposite the direction of the spiral is equal to or above a threshold. We developed an analytical relation of the unpinning phase with the initial phase, the pacing ratio, and the field strength. This is then verified in experiments and simulations.
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Affiliation(s)
- S V Amrutha
- Department of Physics, National Institute of Technology Karnataka, Mangalore 575025, India
| | - Anupama Sebastian
- Department of Physics, National Institute of Technology Karnataka, Mangalore 575025, India
| | - Puthiyapurayil Sibeesh
- Department of Physics, National Institute of Technology Karnataka, Mangalore 575025, India
| | - Shreyas Punacha
- Department of Physics, National Institute of Technology Karnataka, Mangalore 575025, India
- Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, Washington 98195, USA
| | - T K Shajahan
- Department of Physics, National Institute of Technology Karnataka, Mangalore 575025, India
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Steyer J, Lilienkamp T, Luther S, Parlitz U. The role of pulse timing in cardiac defibrillation. FRONTIERS IN NETWORK PHYSIOLOGY 2022; 2:1007585. [PMID: 36926106 PMCID: PMC10013017 DOI: 10.3389/fnetp.2022.1007585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/28/2022] [Indexed: 01/05/2023]
Abstract
Life-threatening cardiac arrhythmias require immediate defibrillation. For state-of-the-art shock treatments, a high field strength is required to achieve a sufficient success rate for terminating the complex spiral wave (rotor) dynamics underlying cardiac fibrillation. However, such high energy shocks have many adverse side effects due to the large electric currents applied. In this study, we show, using 2D simulations based on the Fenton-Karma model, that also pulses of relatively low energy may terminate the chaotic activity if applied at the right moment in time. In our simplified model for defibrillation, complex spiral waves are terminated by local perturbations corresponding to conductance heterogeneities acting as virtual electrodes in the presence of an external electric field. We demonstrate that time series of the success rate for low energy shocks exhibit pronounced peaks which correspond to short intervals in time during which perturbations aiming at terminating the chaotic fibrillation state are (much) more successful. Thus, the low energy shock regime, although yielding very low temporal average success rates, exhibits moments in time for which success rates are significantly higher than the average value shown in dose-response curves. This feature might be exploited in future defibrillation protocols for achieving high termination success rates with low or medium pulse energies.
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Affiliation(s)
- Joshua Steyer
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,Institute for the Dynamics of Complex Systems, Georg-August-Universität Göttingen, Göttingen, Germany.,Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Thomas Lilienkamp
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,Faculty for Applied Mathematics, Physics, and General Science, Computational Physics for Life Science, Nuremberg Institute of Technology Georg Simon Ohm, Nürnberg, Germany
| | - Stefan Luther
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,Institute for the Dynamics of Complex Systems, Georg-August-Universität Göttingen, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen, Germany
| | - Ulrich Parlitz
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,Institute for the Dynamics of Complex Systems, Georg-August-Universität Göttingen, Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Göttingen, Göttingen, Germany
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