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Bai J, Zhang C, Liang Y, Tavares A, Wang L. Impact of Combined Modulation of Two Potassium Ion Currents on Spiral Waves and Turbulent States in the Heart. ENTROPY (BASEL, SWITZERLAND) 2024; 26:446. [PMID: 38920457 PMCID: PMC11202854 DOI: 10.3390/e26060446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/27/2024]
Abstract
In the realm of cardiac research, the control of spiral waves and turbulent states has been a persistent focus for scholars. Among various avenues of investigation, the modulation of ion currents represents a crucial direction. It has been proved that the methods involving combined control of currents are superior to singular approaches. While previous studies have proposed some combination strategies, further reinforcement and supplementation are required, particularly in the context of controlling arrhythmias through the combined regulation of two potassium ion currents. This study employs the Luo-Rudy phase I cardiac model, modulating the maximum conductance of the time-dependent potassium current and the time-independent potassium current, to investigate the effects of this combined modulation on spiral waves and turbulent states. Numerical simulation results indicate that, compared to modulating a single current, combining reductions in the conductance of two potassium ion currents can rapidly control spiral waves and turbulent states in a short duration. This implies that employing blockers for both potassium ion currents concurrently represents a more efficient control strategy. The control outcomes of this study represent a novel and effective combination for antiarrhythmic interventions, offering potential avenues for new antiarrhythmic drug targets.
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Affiliation(s)
- Jing Bai
- School of Statistics and Data Science, Zhuhai College of Science and Technology, Zhuhai 519041, China; (J.B.); (C.Z.)
- Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal
| | - Chunfu Zhang
- School of Statistics and Data Science, Zhuhai College of Science and Technology, Zhuhai 519041, China; (J.B.); (C.Z.)
- Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal
| | - Yanchun Liang
- School of Computer Science, Zhuhai College of Science and Technology, Zhuhai 519041, China
| | - Adriano Tavares
- Department of Industrial Electronics, University of Minho, 4800-058 Guimaraes, Portugal
| | - Lidong Wang
- School of Statistics and Data Science, Zhuhai College of Science and Technology, Zhuhai 519041, China; (J.B.); (C.Z.)
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Hussaini S, Mamyraiym Kyzy A, Schröder-Schetelig J, Lädke SL, Venkatesan V, Diaz-Maue L, Quiñonez Uribe RA, Richter C, Biktashev VN, Majumder R, Krinski V, Luther S. Efficient termination of cardiac arrhythmias using optogenetic resonant feedback pacing. CHAOS (WOODBURY, N.Y.) 2024; 34:031103. [PMID: 38526981 DOI: 10.1063/5.0191519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 01/03/2024] [Indexed: 03/27/2024]
Abstract
Malignant cardiac tachyarrhythmias are associated with complex spatiotemporal excitation of the heart. The termination of these life-threatening arrhythmias requires high-energy electrical shocks that have significant side effects, including tissue damage, excruciating pain, and worsening prognosis. This significant medical need has motivated the search for alternative approaches that mitigate the side effects, based on a comprehensive understanding of the nonlinear dynamics of the heart. Cardiac optogenetics enables the manipulation of cellular function using light, enhancing our understanding of nonlinear cardiac function and control. Here, we investigate the efficacy of optically resonant feedback pacing (ORFP) to terminate ventricular tachyarrhythmias using numerical simulations and experiments in transgenic Langendorff-perfused mouse hearts. We show that ORFP outperforms the termination efficacy of the optical single-pulse (OSP) approach. When using ORFP, the total energy required for arrhythmia termination, i.e., the energy summed over all pulses in the sequence, is 1 mJ. With a success rate of 50%, the energy per pulse is 40 times lower than with OSP with a pulse duration of 10 ms. We demonstrate that even at light intensities below the excitation threshold, ORFP enables the termination of arrhythmias by spatiotemporal modulation of excitability inducing spiral wave drift.
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Affiliation(s)
- S Hussaini
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - A Mamyraiym Kyzy
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - J Schröder-Schetelig
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - S L Lädke
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - V Venkatesan
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - L Diaz-Maue
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
- Research Electronics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - R A Quiñonez Uribe
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - C Richter
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
- WG Cardiovascular Optogenetics, Lab Animal Science Unit, Leibniz Institute for Primate Research, Göttingen 37077, Germany
| | - V N Biktashev
- Department of Mathematics and Statistics, University of Exeter, Exeter EX4 4QF, United Kingdom
| | - R Majumder
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
| | - V Krinski
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
| | - S Luther
- Research Group Biomedical Physics, Max Planck Institute for Dynamics and Self-Organisation, Göttingen 37077, Germany
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Göttingen 37075, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Lower Saxony, Göttingen 37075, Germany
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3
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Buchan S, Kar R, John M, Post A, Razavi M. Electrical Stimulation for Low-Energy Termination of Cardiac Arrhythmias: a Review. Cardiovasc Drugs Ther 2023; 37:323-340. [PMID: 34363570 DOI: 10.1007/s10557-021-07236-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/02/2021] [Indexed: 11/24/2022]
Abstract
Cardiac arrhythmias are a leading cause of morbidity and mortality in the developed world, estimated to be responsible for hundreds of thousands of deaths annually. Our understanding of the electrophysiological mechanisms of such arrhythmias has grown since they were formally characterized in the late nineteenth century, and this has led to the development of numerous devices and therapies that have markedly improved outcomes for patients affected by such conditions. Despite these advancements, the application of a single large shock remains the clinical standard for treating deadly tachyarrhythmias. Such defibrillating shocks are undoubtedly effective in terminating such arrhythmias; however, they are applied without forewarning, contributing to the patient's stress and anxiety; they can be intensely painful; and they can have adverse psychological and physiological effects on patients. In recent years, there has been interest in developing defibrillation protocols that can terminate arrhythmias without crossing the human pain threshold for energy delivery, generally estimated to be between 0.1 and 1 J. In this article, we review existing literature on the development of such low-energy defibrillation methods and their underlying mechanisms, in an attempt to broadly describe the current landscape of these technologies.
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Affiliation(s)
- Skylar Buchan
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX, 77030, USA
| | - Ronit Kar
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX, 77030, USA.,Department of Biomedical Engineering, The University of Texas At Austin, Austin, TX, 78712, USA
| | - Mathews John
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX, 77030, USA
| | - Allison Post
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX, 77030, USA
| | - Mehdi Razavi
- Electrophysiology Clinical Research and Innovations, Texas Heart Institute, 6770 Bertner Avenue, Houston, TX, 77030, USA. .,Division of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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Terminating spiral waves with a single designed stimulus: Teleportation as the mechanism for defibrillation. Proc Natl Acad Sci U S A 2022; 119:e2117568119. [PMID: 35679346 PMCID: PMC9214532 DOI: 10.1073/pnas.2117568119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Many chemical and biological systems can sustain complex spiral wave dynamics. In the heart, spiral waves of electrical activity induce deadly arrhythmias and must be eliminated with a large, system-wide perturbation to restore a healthy rhythm. However, the high-energy shocks required for defibrillation therapies are very painful and can even damage heart tissue. In this study, we demonstrate a method for eliminating spiral waves with what should be the minimal possible stimulus required in space for termination. To do this, we show how a localized perturbation can be designed to annihilate simultaneously all spiral waves both free and bound. This identified mechanism is applicable to any excitable system and, for the heart, may lead to more efficient defibrillation strategies. We identify and demonstrate a universal mechanism for terminating spiral waves in excitable media using an established topological framework. This mechanism dictates whether high- or low-energy defibrillation shocks succeed or fail. Furthermore, this mechanism allows for the design of a single minimal stimulus capable of defibrillating, at any time, turbulent states driven by multiple spiral waves. We demonstrate this method in a variety of computational models of cardiac tissue ranging from simple to detailed human models. The theory described here shows how this mechanism underlies all successful defibrillation and can be used to further develop existing and future low-energy defibrillation strategies.
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Uzelac I, Crowley CJ, Iravanian S, Kim TY, Cho HC, Fenton FH. Methodology for Cross-Talk Elimination in Simultaneous Voltage and Calcium Optical Mapping Measurements With Semasbestic Wavelengths. Front Physiol 2022; 13:812968. [PMID: 35222080 PMCID: PMC8874316 DOI: 10.3389/fphys.2022.812968] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/03/2022] [Indexed: 02/04/2023] Open
Abstract
Most cardiac arrhythmias at the whole heart level result from alteration of cell membrane ionic channels and intracellular calcium concentration ([Ca2+] i ) cycling with emerging spatiotemporal behavior through tissue-level coupling. For example, dynamically induced spatial dispersion of action potential duration, QT prolongation, and alternans are clinical markers for arrhythmia susceptibility in regular and heart-failure patients that originate due to changes of the transmembrane voltage (V m) and [Ca2+] i . We present an optical-mapping methodology that permits simultaneous measurements of the V m - [Ca2+] i signals using a single-camera without cross-talk, allowing quantitative characterization of favorable/adverse cell and tissue dynamical effects occurring from remodeling and/or drugs in heart failure. We demonstrate theoretically and experimentally in six different species the existence of a family of excitation wavelengths, we termed semasbestic, that give no change in signal for one dye, and thus can be used to record signals from another dye, guaranteeing zero cross-talk.
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Affiliation(s)
- Ilija Uzelac
- School of Physics, Georgia Institute of Technology, Atlanta, GA, United States
| | | | - Shahriar Iravanian
- Division of Cardiology, Section of Electrophysiology, Emory University Hospital, Atlanta, GA, United States
| | - Tae Yun Kim
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
| | - Hee Cheol Cho
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States
- Department of Biomedical Engineering, Emory University School of Medicine, Atlanta, GA, United States
- The Sibley Heart Center, Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Flavio H. Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, GA, United States
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6
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Novel Low-Voltage MultiPulse Therapy to Terminate Atrial Fibrillation. JACC Clin Electrophysiol 2021; 7:988-999. [PMID: 33812836 DOI: 10.1016/j.jacep.2020.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/17/2020] [Accepted: 12/23/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVES This first-in-human feasibility study was undertaken to translate the novel low-voltage MultiPulse Therapy (MPT) (Cardialen, Inc., Minneapolis, Minnesota), which was previously been shown to be effective in preclinical studies in terminating atrial fibrillation (AF), into clinical use. BACKGROUND Current treatment options for AF, the most common arrhythmia in clinical practice, have limited success. Previous attempts at treating AF by using implantable devices have been limited by the painful nature of high-voltage shocks. METHODS Forty-two patients undergoing AF ablation were recruited at 6 investigational centers worldwide. Before ablation, electrode catheters were placed in the coronary sinus, right and/or left atrium, for recording and stimulation. After the induction of AF, MPT, which consists of up to a 3-stage sequence of far- and near-field stimulation pulses of varied amplitude, duration, and interpulse timing, was delivered via temporary intracardiac leads. MPT parameters and delivery methods were iteratively optimized. RESULTS In the 14 patients from the efficacy phase, MPT terminated 37 of 52 (71%) of AF episodes, with the lowest median energy of 0.36 J (interquartile range [IQR]: 0.14 to 1.21 J) and voltage of 42.5 V (IQR: 25 to 75 V). Overall, 38% of AF terminations occurred within 2 seconds of MPT delivery (p < 0.0001). Shorter time between AF induction and MPT predicted success of MPT in terminating AF (p < 0.001). CONCLUSIONS MPT effectively terminated AF at voltages and energies known to be well tolerated or painless in some patients. Our results support further studies of the concept of implanted devices for early AF conversion to reduce AF burden, symptoms, and progression.
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7
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Cardiac Spiral Wave Termination by Linear Regional Cooling Toward the Anatomical Boundary of the Heart. J Med Biol Eng 2020. [DOI: 10.1007/s40846-020-00517-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Abstract
Purpose
We hypothesized that linear regional cooling (LRC) toward the atrio-ventricular groove (AV-G) can move the spiral wave (SW) center to the AV-G effectively and terminate SW. The effectiveness of LRC in ex vivo 2D ventricle rabbit experiments was tested.
Methods
We developed an experimental system to operate LRC and optical mapping simultaneously. To realize simultaneous cooling and optical mapping, a transparent cooling device was developed. LRC for 60 s toward 2D subepicardial ventricular myocardium of Langendorff-perfused rabbit hearts (n = 4) was conducted during constant pacing and persistent ventricular tachyarrhythmias (VTs).
Results
Action potential duration at 90% repolarization (APD90) at the cooling area was prolonged by LRC from 187 to 228 ms. 41% of persistent VTs were terminated by LRC (12/29 cases). Cases where the original SW center moved toward the AV-G were observed via optical mapping. However, there were some cases where VT was not terminated by LRC. When the action potential duration (APD) of VT sustained cases were analyzed, LRC prolonged APD, but the APD prolonged area did not move toward the AV-G in most VT sustained cases
Conclusion
Proper LRC toward the AV-G near the original SW center could move this center toward the AV-G and terminate SW excitation.
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8
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Shah AR, Khan MS, Hirahara AM, Lange M, Ranjan R, Dosdall DJ. A real-time system for selectively sensing and pacing the His-bundle during sinus rhythm and ventricular fibrillation. Biomed Eng Online 2020; 19:19. [PMID: 32276597 PMCID: PMC7146996 DOI: 10.1186/s12938-020-00763-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/01/2020] [Indexed: 11/18/2022] Open
Abstract
Background The His–Purkinje (HP) system provides a pathway for the time-synchronous contraction of the heart. His bundle (HB) of the HP system is gaining relevance as a pacing site for treating non-reversible bradyarrhythmia despite limited availability of tools to identify the HB. In this paper, we describe a real-time stimulation and recording system (rt-SRS) to investigate using multi-electrode techniques to identify and selectively pace the HB. The rt-SRS can not only be used in sinus rhythm, but also during ventricular fibrillation (VF). The rt-SRS will also help investigate the so far unknown causal effects of selectively pacing the HB during VF. Methods The rt-SRS consists of preamplifiers, data acquisition cards interfaced with a real-time controller, a current source, and current routing switches on a remote computer, which may be interrupted to stimulate using a host machine. The remote computer hosts a series of algorithms designed to aid in identifying electrodes directly over the HB, to accurately detect activation rates without over-picking, and to deliver stimulation pulses. The performance of the rt-SRS was demonstrated in seven isolated, perfused rabbit hearts. Results The rt-SRS can visualize up to 96 channels of raw data, and spatial derivative data at 6.25-kHz sampling rate with an input-referred noise of 100 µV. The rt-SRS can send up to ± 150 V of stimuli pulses to any of the 96 channels. In the rabbit experiments, HB activations were detected in 18 ± 6.8% of the 64 electrodes used during VF. Conclusions The rt-SRS is capable of measuring and responding to cardiac electrophysiological phenomena in real-time with precisely timed and placed electrical stimuli. This rt-SRS was shown to be an effective research tool by successfully detecting and quantifying HB activations and delivering stimulation pulses to selected electrodes in real-time.
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Affiliation(s)
- Ankur R Shah
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT, 84112, USA
| | - Muhammad S Khan
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT, 84112, USA
| | - Annie M Hirahara
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT, 84112, USA
| | - Matthias Lange
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT, 84112, USA
| | - Ravi Ranjan
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT, 84112, USA.,Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT, 84112, USA
| | - Derek J Dosdall
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, 84112, USA. .,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT, 84112, USA. .,Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT, 84112, USA. .,Division of Cardiothoracic Surgery, School of Medicine, Department of Surgery, The University of Utah, Salt Lake City, UT, 84112, USA.
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9
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Uzelac I, Crowley CJ, Fenton FH. Isosbestic Point in Optical Mapping; Theoretical and Experimental Determination With Di-4-ANBDQPQ Transmembrane Voltage Sensitive Dye. COMPUTING IN CARDIOLOGY 2019; 46:10.22489/CinC.2019.414. [PMID: 34722782 PMCID: PMC8552219 DOI: 10.22489/cinc.2019.414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Optical mapping methods utilize fluorescence dyes to measure dynamic response of cardiac tissue such as changes in transmembrane potential (Vm). For the commonly used Vm sensitive dyes, a dye absorption and emission spectra shift as Vm changes. Signals relevant to Vm are calculated as a relative fluorescence change with respect to the fluorescence baseline. The amplitude of the change depends on the long-pass (LP) filter cut-on wavelength, placed on the sensor side, and the excitation wavelength. An excitation wavelength near the absorption peak, termed the isosbestic point, results in minimal absorption coefficient change as absorption spectra shifts. Consequentially the fluorescence intensity virtually does not change, when fluorescence across the entire emission spectra is measured, irrelevant of Vm changes. In this study we experimentally determined the isosbestic point for a near infrared dye Di-4-ANBDQPQ. We then present a theoretical study examining the dye linear or non-linear response as the fractional fluorescence change of Vm change, due to emission spectra shift and amplitude change, over a range of excitation wavelengths and LP filters. Linear "optical" response is important to quantify certain aspects of cardiac dynamics such as the action potential (AP) shape and duration, especially when studying drug effects and dynamical substrates for arrhythmia development.
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Affiliation(s)
- Ilija Uzelac
- School of Physics - Georgia Institute of Technology, USA
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10
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Huang J, Ruse RB, Walcott GP, Litovsky S, Bohanan SJ, Gong DW, Kroll MW. Ascending Defibrillation Waveform Significantly Reduces Myocardial Morphological Damage and Injury Current. JACC Clin Electrophysiol 2019; 5:854-862. [PMID: 31320015 DOI: 10.1016/j.jacep.2019.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/19/2019] [Accepted: 04/17/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVES This study tested the hypothesis that a biphasic defibrillation waveform with an ascending first phase (ASC) causes less myocardial damage by pathology and injury current than a standard biphasic truncated exponential (BTE) waveform in a swine model. BACKGROUND Although lifesaving, defibrillation shocks have significant iatrogenic effects that reduce their benefit for patient survival. METHODS An ASC waveform with an 8-ms linear ramp followed by an additional positive 0.5-ms decaying portion with amplitudes of 20 J (ASC 20J) and 25 J (ASC 25J) was used. The control was a 25-J BTE conventional waveform (BTE 25J) RESULTS: The ASC 20J and ASC 25J shocks were both successful in 6 of 6 pigs, but the BTE 25J was successful in only 6 of 14 pigs (p < 0.05). Post-shock ST-segment elevation (injury current) in the right ventricular electrode was significantly greater with BTE 25J than with ASC 20J and ASC 25J. With a blinded pathology reading, hemorrhage, inflammation, thrombi, and necrosis 24 h post-shock were significantly greater with BTE 25J than with ASC 20J and ASC 25J. Troponin levels were also markedly lower at 3, 4, 5, and 6 h post-shock. CONCLUSIONS Defibrillation shocks cause electrophysiological, histological, and biochemical signs of myocardial damage and necrosis. These signs of damage are markedly less for an ASC waveform than for a conventional BTE waveform.
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Affiliation(s)
- Jian Huang
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Gregory P Walcott
- Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama
| | - Silvio Litovsky
- Department of Medicine, Department of Pathology, University of Alabama at Birmingham, Alabama
| | | | - Da-Wei Gong
- School of Medicine, University of Maryland, Baltimore, Maryland
| | - Mark W Kroll
- Department of Biomedical Engineering, University of Minnesota Crystal Bay, Minnesota; Department of Biomedical Engineering, California Polytechnical University, San Luis Obispo, California.
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11
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Ma X, Yuan H, Luan HX, Shi YL, Zeng XL, Wang Y. Elevated soluble ST2 concentration may involve in the progression of atrial fibrillation. Clin Chim Acta 2018; 480:138-142. [DOI: 10.1016/j.cca.2018.02.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 02/03/2023]
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12
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Buran P, Bär M, Alonso S, Niedermayer T. Control of electrical turbulence by periodic excitation of cardiac tissue. CHAOS (WOODBURY, N.Y.) 2017; 27:113110. [PMID: 29195336 DOI: 10.1063/1.5010787] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electrical turbulence in cardiac tissue is associated with arrhythmias such as life-threatening ventricular fibrillation. Recent experimental studies have shown that a sequence of low-energy electrical far-field pulses is able to terminate fibrillation more gently than a single high-energy pulse which causes severe side effects. During this low-energy antifibrillation pacing (LEAP), only tissue near sufficiently large conduction heterogeneities, such as large coronary arteries, is activated. In order to optimize LEAP, we performed extensive simulations of cardiac tissue perforated by blood vessels, employing two alternative cellular models that exhibit electrical turbulence at a similar length scale. Moreover, the scale of blood vessels in our two-dimensional simulations was chosen such that the threshold for single pulse defibrillation matches experimental values. For each of the 100 initial conditions, we tested different electrical field strengths, pulse shapes, numbers of pulses, and periods between the pulses. LEAP is successful for both models, albeit with substantial differences. One model exhibits a spectrum of chaotic activity featuring a narrow peak around a dominant frequency. In this case, the optimal period between low-energy pulses matches this frequency and LEAP greatly reduces the required energy for successful defibrillation. For pulses with larger energies, the system is perturbed such that underdrive pacing becomes advantageous. The spectrum of the second model features a broader peak, resulting in a less pronounced optimal pacing period and a decreased energy reduction. In both cases, pacing with five or six pulses which are separated by the dominant period maximizes the energy reduction.
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Affiliation(s)
- Pavel Buran
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Markus Bär
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
| | - Sergio Alonso
- Department of Physics, Universitat Politècnica de Catalunya, Av. Dr. Marañón 44, 08028 Barcelona, Spain
| | - Thomas Niedermayer
- Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany
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13
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Bittihn P, Berg S, Parlitz U, Luther S. Emergent dynamics of spatio-temporal chaos in a heterogeneous excitable medium. CHAOS (WOODBURY, N.Y.) 2017; 27:093931. [PMID: 28964139 DOI: 10.1063/1.4999604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Self-organized activation patterns in excitable media such as spiral waves and spatio-temporal chaos underlie dangerous cardiac arrhythmias. While the interaction of single spiral waves with different types of heterogeneity has been studied extensively, the effect of heterogeneity on fully developed spatio-temporal chaos remains poorly understood. We investigate how the complexity and stability properties of spatio-temporal chaos in the Bär-Eiswirth model of excitable media depend on the heterogeneity of the underlying medium. We employ different measures characterizing the chaoticity of the system and find that the spatial arrangement of multiple discrete lower excitability regions has a strong impact on the complexity of the dynamics. Varying the number, shape, and spatial arrangement of the heterogeneities, we observe strong emergent effects ranging from increases in chaoticity to the complete cessation of chaos, contrasting the expectation from the homogeneous behavior. The implications of our findings for the development and treatment of arrhythmias in the heterogeneous cardiac muscle are discussed.
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Affiliation(s)
- Philip Bittihn
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Sebastian Berg
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Ulrich Parlitz
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Stefan Luther
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany
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Ji YC, Uzelac I, Otani N, Luther S, Gilmour RF, Cherry EM, Fenton FH. Synchronization as a mechanism for low-energy anti-fibrillation pacing. Heart Rhythm 2017; 14:1254-1262. [DOI: 10.1016/j.hrthm.2017.05.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Indexed: 10/19/2022]
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15
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Rababah AS, Walsh SJ, Manoharan G, Walsh PR, Escalona OJ. Intracardiac impedance response during acute AF internal cardioversion using novel rectilinear and capacitor-discharge waveforms. Physiol Meas 2016; 37:1129-45. [PMID: 27328164 DOI: 10.1088/0967-3334/37/7/1129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Intracardiac impedance (ICI) is a major determinant of success during internal cardioversion of atrial fibrillation (AF). However, there have been few studies that have examined the dynamic behaviour of atrial impedance during internal cardioversion in relation to clinical outcome. In this study, voltage and current waveforms captured during internal cardioversion of acute AF in ovine models using novel radiofrequency (RF) generated low-tilt rectilinear and conventional capacitor-discharge based shock waveforms were retrospectively analysed using a digital signal processing algorithm to investigate the dynamic behaviour of atrial impedance during cardioversion. The algorithm was specifically designed to facilitate the simultaneous analysis of multiple impedance parameters, including: mean intracardiac impedance (Z M), intracardiac impedance variance (ICIV) and impedance amplitude spectrum area (IAMSA) for each cardioversion event. A significant reduction in ICI was observed when comparing two successive shocks of increasing energy where cardioversion outcome was successful. In addition, ICIV and IAMSA variables were found to inversely correlate to the magnitude of energy delivered; with a stronger correlation found to the former parameter. In conclusion, ICIV and IAMSA have been evidenced as two key dynamic intracardiac impedance variables that may prove useful in better understanding of the cardioversion process and that could potentially act as prognostic markers with respect to clinical outcome.
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Affiliation(s)
- A S Rababah
- School of Engineering, Engineering Research Institute, Ulster University, Newtownabbey, UK
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16
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Arevalo HJ, Boyle PM, Trayanova NA. Computational rabbit models to investigate the initiation, perpetuation, and termination of ventricular arrhythmia. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:185-94. [PMID: 27334789 DOI: 10.1016/j.pbiomolbio.2016.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/13/2016] [Indexed: 12/29/2022]
Abstract
Current understanding of cardiac electrophysiology has been greatly aided by computational work performed using rabbit ventricular models. This article reviews the contributions of multiscale models of rabbit ventricles in understanding cardiac arrhythmia mechanisms. This review will provide an overview of multiscale modeling of the rabbit ventricles. It will then highlight works that provide insights into the role of the conduction system, complex geometric structures, and heterogeneous cellular electrophysiology in diseased and healthy rabbit hearts to the initiation and maintenance of ventricular arrhythmia. Finally, it will provide an overview on the contributions of rabbit ventricular modeling on understanding the mechanisms underlying shock-induced defibrillation.
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Affiliation(s)
- Hermenegild J Arevalo
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Simula Research Laboratory, Oslo, Norway
| | - Patrick M Boyle
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Natalia A Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
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17
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Guevara MR, Shrier A, Orlowski J, Glass L. George Ralph Mines (1886-1914): the dawn of cardiac nonlinear dynamics. J Physiol 2016; 594:2361-71. [PMID: 27126414 DOI: 10.1113/jp270891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/29/2016] [Indexed: 11/08/2022] Open
Affiliation(s)
- Michael R Guevara
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Alvin Shrier
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - John Orlowski
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Leon Glass
- Department of Physiology, McGill University, Montreal, Quebec, Canada
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18
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Glass L. Dynamical disease: Challenges for nonlinear dynamics and medicine. CHAOS (WOODBURY, N.Y.) 2015; 25:097603. [PMID: 26428556 DOI: 10.1063/1.4915529] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Dynamical disease refers to illnesses that are associated with striking changes in the dynamics of some bodily function. There is a large literature in mathematics and physics which proposes mathematical models for the physiological systems and carries out analyses of the properties of these models using nonlinear dynamics concepts involving analyses of the stability and bifurcations of attractors. This paper discusses how these concepts can be applied to medicine.
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Affiliation(s)
- Leon Glass
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6, Canada
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19
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Gutbrod SR, Efimov IR. A shocking past: a walk through generations of defibrillation development. IEEE Trans Biomed Eng 2015; 61:1466-73. [PMID: 24759279 DOI: 10.1109/tbme.2014.2301035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Defibrillation is one of the most successful and widely recognized applications of electrotherapy. Yet the historical road to its first successful application in a patient and the innovative adaptation to an implantable device is marred with unexpected turns, political and personal setbacks, and public and scientific condemnation at each new idea. Driven by dedicated scientists and ever-advancing creative applications of new technologies, from electrocardiography to high density mapping and computational simulations, the field of defibrillation persevered and continued to evolve to the life-saving tool it is today. In addition to critical technological advances, the history of defibrillation is also marked by the plasticity of the theory of defibrillation. The advancing theories of success have propelled the campaign for reducing the defibrillation energy requirement, instilling hope in the development of a painless and harmless electrical defibrillation strategy.
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20
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Trayanova NA, Rantner LJ. New insights into defibrillation of the heart from realistic simulation studies. Europace 2014; 16:705-13. [PMID: 24798960 PMCID: PMC4010179 DOI: 10.1093/europace/eut330] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/17/2013] [Indexed: 11/12/2022] Open
Abstract
Cardiac defibrillation, as accomplished nowadays by automatic, implantable devices, constitutes the most important means of combating sudden cardiac death. Advancing our understanding towards a full appreciation of the mechanisms by which a shock interacts with the heart, particularly under diseased conditions, is a promising approach to achieve an optimal therapy. The aim of this article is to assess the current state-of-the-art in whole-heart defibrillation modelling, focusing on major insights that have been obtained using defibrillation models, primarily those of realistic heart geometry and disease remodelling. The article showcases the contributions that modelling and simulation have made to our understanding of the defibrillation process. The review thus provides an example of biophysically based computational modelling of the heart (i.e. cardiac defibrillation) that has advanced the understanding of cardiac electrophysiological interaction at the organ level, and has the potential to contribute to the betterment of the clinical practice of defibrillation.
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Affiliation(s)
- Natalia A. Trayanova
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 3400 N Charles Street, 216 Hackerman Hall, Baltimore, MD 21218, USA
- Institute for Computational Medicine, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
| | - Lukas J. Rantner
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, 3400 N Charles Street, 216 Hackerman Hall, Baltimore, MD 21218, USA
- Institute for Computational Medicine, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
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21
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Affiliation(s)
- Chu-Pak Lau
- Cardiology Division, Department of Medicine, Queen Mary Hospital (C.-P.L., C.-W.S., H.-F.T.) and Research Center of Heart, Brain, Hormone and Healthy Ageing, Li Ka Shing Faculty of Medicine (C.-W.S., H.-F.T.), University of Hong Kong, Hong Kong SAR, China
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22
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Trayanova NA, Boyle PM. Advances in modeling ventricular arrhythmias: from mechanisms to the clinic. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2013; 6:209-24. [PMID: 24375958 DOI: 10.1002/wsbm.1256] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/16/2013] [Accepted: 11/12/2013] [Indexed: 11/12/2022]
Abstract
Modern cardiovascular research has increasingly recognized that heart models and simulation can help interpret an array of experimental data and dissect important mechanisms and interrelationships, with developments rooted in the iterative interaction between modeling and experimentation. This article reviews the progress made in simulating cardiac electrical behavior at the level of the organ and, specifically, in the development of models of ventricular arrhythmias and fibrillation, as well as their termination (defibrillation). The ability to construct multiscale models of ventricular arrhythmias, representing integrative behavior from the molecule to the entire organ, has enabled mechanistic inquiry into the dynamics of ventricular arrhythmias in the diseased myocardium, in understanding drug-induced proarrhythmia, and in the development of new modalities for defibrillation, to name a few. In this article, we also review the initial use of ventricular models of arrhythmia in personalized diagnosis, treatment planning, and prevention of sudden cardiac death. Implementing individualized cardiac simulations at the patient bedside is poised to become one of the most thrilling examples of computational science and engineering approaches in translational medicine.
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Affiliation(s)
- Natalia A Trayanova
- Institute for Computational Medicine, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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23
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Janardhan AH, Gutbrod SR, Li W, Lang D, Schuessler RB, Efimov IR. Multistage electrotherapy delivered through chronically-implanted leads terminates atrial fibrillation with lower energy than a single biphasic shock. J Am Coll Cardiol 2013; 63:40-8. [PMID: 24076284 DOI: 10.1016/j.jacc.2013.07.098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 07/24/2013] [Accepted: 07/27/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES The goal of this study was to develop a low-energy, implantable device-based multistage electrotherapy (MSE) to terminate atrial fibrillation (AF). BACKGROUND Previous attempts to perform cardioversion of AF by using an implantable device were limited by the pain caused by use of a high-energy single biphasic shock (BPS). METHODS Transvenous leads were implanted into the right atrium (RA), coronary sinus, and left pulmonary artery of 14 dogs. Self-sustaining AF was induced by 6 ± 2 weeks of high-rate RA pacing. Atrial defibrillation thresholds of standard versus experimental electrotherapies were measured in vivo and studied by using optical imaging in vitro. RESULTS The mean AF cycle length (CL) in vivo was 112 ± 21 ms (534 beats/min). The impedances of the RA-left pulmonary artery and RA-coronary sinus shock vectors were similar (121 ± 11 Ω vs. 126 ± 9 Ω; p = 0.27). BPS required 1.48 ± 0.91 J (165 ± 34 V) to terminate AF. In contrast, MSE terminated AF with significantly less energy (0.16 ± 0.16 J; p < 0.001) and significantly lower peak voltage (31.1 ± 19.3 V; p < 0.001). In vitro optical imaging studies found that AF was maintained by localized foci originating from pulmonary vein-left atrium interfaces. MSE Stage 1 shocks temporarily disrupted localized foci; MSE Stage 2 entrainment shocks continued to silence the localized foci driving AF; and MSE Stage 3 pacing stimuli enabled consistent RA-left atrium activation until sinus rhythm was restored. CONCLUSIONS Low-energy MSE significantly reduced the atrial defibrillation thresholds compared with BPS in a canine model of AF. MSE may enable painless, device-based AF therapy.
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Affiliation(s)
- Ajit H Janardhan
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri
| | - Sarah R Gutbrod
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Wenwen Li
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Di Lang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Richard B Schuessler
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri; Department of Surgery, Cardiothoracic Division, Washington University School of Medicine, St. Louis, Missouri
| | - Igor R Efimov
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri; Department of Biomedical Engineering, Washington University, St. Louis, Missouri.
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24
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25
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Rantner LJ, Tice BM, Trayanova NA. Terminating ventricular tachyarrhythmias using far-field low-voltage stimuli: mechanisms and delivery protocols. Heart Rhythm 2013; 10:1209-17. [PMID: 23628521 DOI: 10.1016/j.hrthm.2013.04.027] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Indexed: 12/01/2022]
Abstract
BACKGROUND Low-voltage termination of ventricular tachycardia (VT) and atrial fibrillation has shown promising results; however, the mechanisms and full range of applications remain unexplored. OBJECTIVES To elucidate the mechanisms for low-voltage cardioversion and defibrillation and to develop an optimal low-voltage defibrillation protocol. METHODS We developed a detailed magnetic resonance imaging-based computational model of the rabbit right ventricular wall. We applied multiple low-voltage far-field stimuli of various strengths (≤1 V/cm) and stimulation rates in VT and ventricular fibrillation (VF). RESULTS Of the 5 stimulation rates tested, stimuli applied at 16% or 88% of the VT cycle length (CL) were most effective in cardioverting VT, the mechanism being consecutive excitable gap decreases. Stimuli given at 88% of the VF CL defibrillated successfully, whereas a faster stimulation rate (16%) often failed because the fast stimuli did not capture enough tissue. In this model, defibrillation threshold energy for multiple low-voltage stimuli at 88% of VF CL was 0.58% of the defibrillation threshold energy for a single strong biphasic shock. Based on the simulation results, a novel 2-stage defibrillation protocol was proposed. The first stage converted VF into VT by applying low-voltage stimuli at times of maximal excitable gap, capturing large tissue volume and synchronizing depolarization; the second stage terminated VT. The energy required for successful defibrillation using this protocol was 57.42% of the energy for low-voltage defibrillation when stimulating at 88% of VF CL. CONCLUSIONS A novel 2-stage low-voltage defibrillation protocol using the excitable gap extent to time multiple stimuli defibrillated VF with the least energy by first converting VF into VT and then terminating VT.
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Affiliation(s)
- Lukas J Rantner
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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26
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Winkle RA. Evolution of the Implantable Cardioverter-Defibrillator. J Am Coll Cardiol 2012; 60:2399-401. [DOI: 10.1016/j.jacc.2012.07.066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 07/24/2012] [Indexed: 11/28/2022]
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27
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Bittihn P, Hörning M, Luther S. Negative curvature boundaries as wave emitting sites for the control of biological excitable media. PHYSICAL REVIEW LETTERS 2012; 109:118106. [PMID: 23005683 DOI: 10.1103/physrevlett.109.118106] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Indexed: 06/01/2023]
Abstract
Understanding the interaction of electric fields with the complex anatomy of biological excitable media is key to optimizing control strategies for spatiotemporal dynamics in those systems. On the basis of a bidomain description, we provide a unified theory for the electric-field-induced depolarization of the substrate near curved boundaries of generalized shapes, resulting in the localized recruitment of control sites. Our findings are confirmed in experiments on cardiomyocyte cell cultures and supported by two-dimensional numerical simulations on a cross section of a rabbit ventricle.
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Affiliation(s)
- Philip Bittihn
- Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.
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28
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A novel electrode placement strategy for low-energy internal cardioversion of atrial fibrillation: a simulation study. Int J Cardiol 2012; 158:149-52. [PMID: 22560917 DOI: 10.1016/j.ijcard.2012.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 04/08/2012] [Indexed: 11/22/2022]
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29
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Circulation: Arrhythmia and Electrophysiology
Editors’ Picks. Circ Arrhythm Electrophysiol 2012. [DOI: 10.1161/circep.112.973305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The following articles are being highlighted as part of
Circulation: Arrhythmia and Electrophysiology’s
Topic Review series. This series will summarize the most important manuscripts, as selected by the editors, published in
Circulation: Arrhythmia and Electrophysiology, Circulation
, and the other
Circulation
subspecialty journals. The studies included in this article represent the most read manuscripts published on the topic of arrhythmia devices (defibrillation, pacing, pacemakers, heart arrest, and resuscitation) in 2010 and 2011.
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