1
|
Okada JI, Washio T, Sugiura S, Hisada T. Low-energy defibrillation using a base-apex epicardial electrode. Pacing Clin Electrophysiol 2023; 46:1325-1332. [PMID: 37830313 DOI: 10.1111/pace.14832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/17/2023] [Accepted: 09/10/2023] [Indexed: 10/14/2023]
Abstract
BACKGROUND Current implantable cardioverter defibrillators (ICDs) require electric conduction with high voltage and high energy, which can impair cardiac function and induce another malignant arrhythmia. As a result, there has been a demand for an ICD that can effectively operate with lower energy to mitigate the risks of a strong electric shock. METHODS A pair of sheet-shaped electrodes covering the heart were analyzed in three configurations (top-bottom, left-right, and front-back) using a heart simulator. We also varied the distance between the two electrodes (clearance) to identify the electrode shape with the lowest defibrillation threshold (DFT). We also investigated the ICD shock waveform, shock direction, and the effect of the backside insulator of the electrode. RESULTS The DFT was high when the clearance was too small and the DFT was high even when the clearance was too large, suggesting that an optimal value clearance. The top-bottom electrodes with optimal clearance showed the lowest DFT when the biphasic shocks set the top electrode to a high potential first and then the bottom electrode was set to a high potential. An interval between a first shock waveform and a second shock waveform should be provided for low-energy defibrillation. Because the insulator prevents unnecessary current flow to the backside, the DFT of the electrodes with insulators is less than those without insulators. CONCLUSION Painless defibrillation using sheet-shaped electrodes on the epicardium is predicated on the basis of results using a heart simulator.
Collapse
Affiliation(s)
- Jun-Ichi Okada
- UT-Heart Inc., Setagaya-ku, Tokyo, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-shi, Chiba, Japan
| | - Takumi Washio
- UT-Heart Inc., Setagaya-ku, Tokyo, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-shi, Chiba, Japan
| | | | | |
Collapse
|
2
|
Ruiz-Fernández AR, Campos L, Villanelo F, Garate JA, Perez-Acle T. Protein-Mediated Electroporation in a Cardiac Voltage-Sensing Domain Due to an nsPEF Stimulus. Int J Mol Sci 2023; 24:11397. [PMID: 37511161 PMCID: PMC10379607 DOI: 10.3390/ijms241411397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/15/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
This study takes a step in understanding the physiological implications of the nanosecond pulsed electric field (nsPEF) by integrating molecular dynamics simulations and machine learning techniques. nsPEF, a state-of-the-art technology, uses high-voltage electric field pulses with a nanosecond duration to modulate cellular activity. This investigation reveals a relatively new and underexplored phenomenon: protein-mediated electroporation. Our research focused on the voltage-sensing domain (VSD) of the NaV1.5 sodium cardiac channel in response to nsPEF stimulation. We scrutinized the VSD structures that form pores and thereby contribute to the physical chemistry that governs the defibrillation effect of nsPEF. To do so, we conducted a comprehensive analysis involving the clustering of 142 replicas simulated for 50 ns under nsPEF stimuli. We subsequently pinpointed the representative structures of each cluster and computed the free energy between them. We find that the selected VSD of NaV1.5 forms pores under nsPEF stimulation, but in a way that significant differs from the traditional VSD opening. This study not only extends our understanding of nsPEF and its interaction with protein channels but also adds a new effect to further study.
Collapse
Affiliation(s)
| | - Leonardo Campos
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
| | - Felipe Villanelo
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
| | - Jose Antonio Garate
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
- Millennium Nucleus im NanoBioPhysics, Universidad de Valparaiso, Valparaiso 2351319, Chile
| | - Tomas Perez-Acle
- Computational Biology Lab, Fundación Ciencia & Vida, Santiago 7780272, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago 8420524, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaiso 2360102, Chile
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
Varghese F, Philpott JM, Neuber JU, Hargrave B, Zemlin CW. Surgical Ablation of Cardiac Tissue with Nanosecond Pulsed Electric Fields in Swine. Cardiovasc Eng Technol 2023; 14:52-59. [PMID: 35705890 DOI: 10.1007/s13239-022-00634-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 05/18/2022] [Indexed: 11/02/2022]
Abstract
BACKGROUND Myocardial tissue can be ablated by the application nanosecond pulsed fields (nsPEFs). The applied electric fields irreversibly permeabilize cell membranes and thereby kill myocytes while leaving the extracellular matrix intact. METHODS In domestic pigs (n = 10), hearts were exposed via sternotomy and either ablated in vivo ([Formula: see text] = 5) or in excised, Langendorff-perfused hearts ([Formula: see text] = 5). The nsPEFs consisted of 6-36 pulses of 300 ns each, delivered at 3-6 Hz; the voltage applied varied from 10 to 12 kV. Atrial lesions were either created after inserting the bottom jaw of the bipolar clamp into the atrium via a purse string incision (2-3 lesions per atrium) or by clamping a double layer of tissue at the appendages (one lesion per atrium). Ventricular lesions were created after an incision at the apex. The transmurality of each lesion was determined at three points along the lesion using a triphenyl tetrazolium chloride (TTC) stain. RESULTS All 27 atrial lesions were transmural. This includes 13/13 purse string lesions (39/39 sections, tissue thickness 2.5-4.5 mm) and 14/14 appendage lesions (42/42 sections, tissue thickness 8-12 mm). All 3 right ventricular lesions were transmural (9/9 sections, 18 pulses per lesion). Left ventricular lesions were always transmural for 36 pulses (3/3 lesions, 9/9 sections). All lesions have highly consistent width across the wall. There were no pulse-induced arrhythmias or other complications during the procedure. CONCLUSIONS nsPEF ablation reliably created acute lesions in porcine atrial and ventricular myocardium. It has far better penetration and is faster than both radiofrequency ablation and cryoablation and it is free from thermal side effects.
Collapse
Affiliation(s)
- Frency Varghese
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA
- Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
- Department of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jonathan M Philpott
- Department of Surgery, Eastern Virginia Medical School, Norfolk, VA, USA
- Mid-Atlantic Thoracic Surgeons, Sentara Heart Hospital, Norfolk, VA, USA
| | - Johanna U Neuber
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA
- Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
| | - Barbara Hargrave
- Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
| | - Christian W Zemlin
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA.
- Center for Bioelectrics, Old Dominion University, Norfolk, VA, USA.
- Division of Cardiothoracic Surgery, Washington University School of Medicine, 660 S Euclid Ave, St. Louis, MO, 63110, USA.
| |
Collapse
|
5
|
Sowa PW, Kiełbik AS, Pakhomov AG, Gudvangen E, Mangalanathan U, Adams V, Pakhomova ON. How to alleviate cardiac injury from electric shocks at the cellular level. Front Cardiovasc Med 2022; 9:1004024. [PMID: 36620647 PMCID: PMC9812960 DOI: 10.3389/fcvm.2022.1004024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022] Open
Abstract
Electric shocks, the only effective therapy for ventricular fibrillation, also electroporate cardiac cells and contribute to the high-mortality post-cardiac arrest syndrome. Copolymers such as Poloxamer 188 (P188) are known to preserve the membrane integrity and viability of electroporated cells, but their utility against cardiac injury from cardiopulmonary resuscitation (CPR) remains to be established. We studied the time course of cell killing, mechanisms of cell death, and protection with P188 in AC16 human cardiomyocytes exposed to micro- or nanosecond pulsed electric field (μsPEF and nsPEF) shocks. A 3D printer was customized with an electrode holder to precisely position electrodes orthogonal to a cell monolayer in a nanofiber multiwell plate. Trains of nsPEF shocks (200, 300-ns pulses at 1.74 kV) or μsPEF shocks (20, 100-μs pulses at 300 V) produced a non-uniform electric field enabling efficient measurements of the lethal effect in a wide range of the electric field strength. Cell viability and caspase 3/7 expression were measured by fluorescent microscopy 2-24 h after the treatment. nsPEF shocks caused little or no caspase 3/7 activation; most of the lethally injured cells were permeable to propidium dye already at 2 h after the exposure. In contrast, μsPEF shocks caused strong activation of caspase 3/7 at 2 h and the number of dead cells grew up to 24 h, indicating the prevalence of the apoptotic death pathway. P188 at 0.2-1% reduced cell death, suggesting its potential utility in vivo to alleviate electric injury from defibrillation.
Collapse
Affiliation(s)
- Pamela W. Sowa
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, United States,Laboratory of Molecular and Experimental Cardiology, Heart Center Dresden, Technische Universität Dresden, Dresden, Germany,Department of Cardiology and Angiology, University Hospital Tübingen, Eberhard Karls University of Tübingen, Tübingen, Germany,*Correspondence: Pamela W. Sowa,
| | - Aleksander S. Kiełbik
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, United States,Department of Molecular and Cellular Biology, Faculty of Pharmacy, Wrocław Medical University, Wrocław, Poland
| | - Andrei G. Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, United States
| | - Emily Gudvangen
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, United States
| | - Uma Mangalanathan
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, United States
| | - Volker Adams
- Laboratory of Molecular and Experimental Cardiology, Heart Center Dresden, Technische Universität Dresden, Dresden, Germany
| | - Olga N. Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, United States
| |
Collapse
|
6
|
Kulangareth NV, Magtibay K, Massé S, Krishnakumar Nair, Dorian P, Nanthakumar K, Umapathy K. An In-Silico model for evaluating the directional shock vectors in terminating and modulating rotors. Comput Biol Med 2022; 146:105665. [DOI: 10.1016/j.compbiomed.2022.105665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/03/2022] [Accepted: 05/19/2022] [Indexed: 11/27/2022]
|
7
|
Moreno A, Walton RD, Bernus O, Vigmond EJ, Bayer JD. Low-energy, single-pulse surface stimulation defibrillates large mammalian ventricles. Heart Rhythm 2021; 19:308-317. [PMID: 34648972 DOI: 10.1016/j.hrthm.2021.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/27/2021] [Accepted: 10/06/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Strong electric shocks are the gold standard for ventricular defibrillation but are associated with pain and tissue damage. We hypothesized that targeting the excitable gap (EG) of reentry with low-energy surface stimulation is a less damaging and painless alternative for ventricular defibrillation. OBJECTIVE The purpose of this study was to determine the conditions under which low-energy surface stimulation defibrillates large mammalian ventricles. METHODS Low-energy surface stimulation was delivered with five electrodes that were 7 cm long and placed 1-2 cm apart on the endocardial and epicardial surfaces of perfused pig left ventricle (LV). Rapid pacing (>4 Hz) was used to induce reentry from a single electrode. A 2 ms defibrillation pulse ≤0.5 A was delivered from all electrodes with a varied time delay from the end of the induction protocol (0.1-5 seconds). Optical mapping was performed and arrhythmia dynamics analyzed. For mechanistic insight, simulations of the VF induction and defibrillation protocols were performed in silico with an LV model emulating the experimental conditions and electrodes placed 0.25-2 cm apart. RESULTS In living LV, reentry was induced with varying complexity and dominant frequencies ranging between 3.5 to 6.2 Hz over 8 seconds postinitiation. Low-energy defibrillation was achieved with energy <60 mJ and electrode separations up to 2 cm for less complex arrhythmia. In simulations, defibrillation consistently occurred when stimulation captured >75% of the EG, which blocked reentry <2.9 mm in front of the leading reentrant wavefront. CONCLUSION Defibrillation with low-energy, single-pulse surface stimulation is feasible with energies below the human pain threshold (100 mJ). Optimal defibrillation occurs when arrhythmia complexity is minimal and electrodes capture >75% of the EG.
Collapse
Affiliation(s)
- Angel Moreno
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France
| | - Richard D Walton
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France; INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Olivier Bernus
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France; INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Edward J Vigmond
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France
| | - Jason D Bayer
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France.
| |
Collapse
|
8
|
Neuber JU, Pakhomov AG, Zemlin CW. Electroporation safety factor of 300 nanosecond and 10 millisecond defibrillation in Langendorff-perfused rabbit hearts. PLoS One 2021; 16:e0257287. [PMID: 34559811 DOI: 10.1371/journal.pone.0257287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 08/30/2021] [Indexed: 11/19/2022] Open
Abstract
AIMS Recently, a new defibrillation modality using nanosecond pulses was shown to be effective at much lower energies than conventional 10 millisecond monophasic shocks in ex vivo experiments. Here we compare the safety factors of 300 nanosecond and 10 millisecond shocks to assess the safety of nanosecond defibrillation. METHODS AND RESULTS The safety factor, i.e. the ratio of median effective doses (ED50) for electroporative damage and defibrillation, was assessed for nanosecond and conventional (millisecond) defibrillation shocks in Langendorff-perfused New Zealand white rabbit hearts. In order to allow for multiple shock applications in a single heart, a pair of needle electrodes was used to apply shocks of varying voltage. Propidium iodide (PI) staining at the surface of the heart showed that nanosecond shocks had a slightly lower safety factor (6.50) than millisecond shocks (8.69), p = 0.02; while PI staining cross-sections in the electrode plane showed no significant difference (5.38 for 300 ns shocks and 6.29 for 10 ms shocks, p = 0.22). CONCLUSIONS In Langendorff-perfused rabbit hearts, nanosecond defibrillation has a similar safety factor as millisecond defibrillation, between 5 and 9, suggesting that nanosecond defibrillation can be performed safely.
Collapse
|
9
|
Abstract
While electrical stimulation with pulses of milli- or microsecond duration is possible without electroporation, stimulation with nanosecond pulses typically entails electroporation, and nanosecond pulses can even cause electroporation without stimulation. A recently proposed explanation for this intriguing finding is that stimulation requires not only that a threshold membrane potential is reached, but also that it is sustained for a certain time tmin, while electroporation occurs almost immediately after a higher threshold potential is reached. Here we analytically derive stimulation and electroporation thresholds for membranes that satisfy these assumptions. We analyze the safety factor, i.e. the ratio between electroporation and stimulation threshold and its dependence on pulse duration, membrane charging time constant, and tmin. We find that the safety factor is sharply reduced if both the pulse duration and the membrane charging time constant are below tmin. We discuss different approaches to get models with varying tmin that could be used to experimentally test this theory and cardiac applications.
Collapse
Affiliation(s)
- Christian W Zemlin
- Division of Cardiothoracic Surgery, Washington University School of Medicine, Campus Box 8234, 660 S Euclid Ave, St. Louis, MO 63110, USA.
| |
Collapse
|
10
|
Sözer EB, Pakhomov AG, Semenov I, Casciola M, Kim V, Vernier PT, Zemlin CW. Analysis of electrostimulation and electroporation by high repetition rate bursts of nanosecond stimuli. Bioelectrochemistry 2021; 140:107811. [PMID: 33862549 DOI: 10.1016/j.bioelechem.2021.107811] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 12/16/2022]
Abstract
Exposures to short-duration, strong electric field pulses have been utilized for stimulation, ablation, and the delivery of molecules into cells. Ultrashort, nanosecond duration pulses have shown unique benefits, but they require higher field strengths. One way to overcome this requirement is to use trains of nanosecond pulses with high repetition rates, up to the MHz range. Here we present a theoretical model to describe the effects of pulse trains on the plasma membrane and intracellular membranes modeled as resistively charged capacitors. We derive the induced membrane potential and the stimulation threshold as functions of pulse number, pulse duration, and repetition rate. This derivation provides a straightforward method to calculate the membrane charging time constant from experimental data. The derived excitation threshold agrees with nerve stimulation experiments, indicating that nanosecond pulses are not more effective than longer pulses in charging nerve fibers. The derived excitation threshold does not, however, correctly predict the nanosecond stimulation of cardiomyocytes. We show that a better agreement is possible if multiple charging time constants are considered. Finally, we expand the model to intracellular membranes and show that pulse trains do not lead to charge buildup, but can create significant oscillations of the intracellular membrane potential.
Collapse
Affiliation(s)
- Esin B Sözer
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Vitalii Kim
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - P Thomas Vernier
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| |
Collapse
|
11
|
李 伟, 谢 佳, 彭 莉, 魏 良, 王 双, 李 永. [Recent advances in external cardiac defibrillation techniques]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2020; 37:1095-1100. [PMID: 33369350 PMCID: PMC9929988 DOI: 10.7507/1001-5515.202003013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Indexed: 06/12/2023]
Abstract
As an important medical electronic equipment for the cardioversion of malignant arrhythmia such as ventricular fibrillation and ventricular tachycardia, cardiac external defibrillators have been widely used in the clinics. However, the resuscitation success rate for these patients is still unsatisfied. In this paper, the recent advances of cardiac external defibrillation technologies is reviewed. The potential mechanism of defibrillation, the development of novel defibrillation waveform, the factors that may affect defibrillation outcome, the interaction between defibrillation waveform and ventricular fibrillation waveform, and the individualized patient-specific external defibrillation protocol are analyzed and summarized. We hope that this review can provide helpful reference for the optimization of external defibrillator design and the individualization of clinical application.
Collapse
Affiliation(s)
- 伟明 李
- 陆军军医大学 生物医学工程与影像医学系(重庆 400038)Department of Biomedical Engineering and Imaging Medicine, Army Medical University, Chongqing 400038, P.R.China
| | - 佳玲 谢
- 陆军军医大学 生物医学工程与影像医学系(重庆 400038)Department of Biomedical Engineering and Imaging Medicine, Army Medical University, Chongqing 400038, P.R.China
| | - 莉 彭
- 陆军军医大学 生物医学工程与影像医学系(重庆 400038)Department of Biomedical Engineering and Imaging Medicine, Army Medical University, Chongqing 400038, P.R.China
| | - 良 魏
- 陆军军医大学 生物医学工程与影像医学系(重庆 400038)Department of Biomedical Engineering and Imaging Medicine, Army Medical University, Chongqing 400038, P.R.China
| | - 双卫 王
- 陆军军医大学 生物医学工程与影像医学系(重庆 400038)Department of Biomedical Engineering and Imaging Medicine, Army Medical University, Chongqing 400038, P.R.China
| | - 永勤 李
- 陆军军医大学 生物医学工程与影像医学系(重庆 400038)Department of Biomedical Engineering and Imaging Medicine, Army Medical University, Chongqing 400038, P.R.China
| |
Collapse
|
12
|
Chiou YA, Cheng LK, Lin SF. Design and Construction of High-Frequency Cardiac Defibrillator for Small Animals. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2020:2614-2617. [PMID: 33018542 DOI: 10.1109/embc44109.2020.9175702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The main goal of this research is to evaluate the defibrillation efficacy with the high-frequency waveform on ventricular fibrillation in small animals. A biphasic defibrillator with adjustable frequency was designed for this study. This custom-designed defibrillator can be adjusted to generate four different frequencies of 125, 250, 500, and 1000 Hz. Six rat hearts were induced VT/VF by electrical induction using the waveform of these four frequencies. Success VT/VF-induction by applying those four frequencies were recorded and observed by optical mapping. The results showed that the VT/VF-induction success rate is increasing along with higher frequencies. The VT/VF-induction success rate is 16% in 125Hz and 250 Hz, 33% in 500 Hz, and 100% in 1000 Hz with S1-S2 protocol at 100 ms coupling interval. Also, using optical mapping technique, shock-induced optical potential showed that only high-frequency waveform exhibited the largest tissue responses in the middle position of the heart. In conclusion, high-frequency (1000Hz) defibrillation waveform has the highest defibrillation efficacy comparing to other lower frequencies used in this study.
Collapse
|
13
|
Pakhomov AG, Pakhomova ON. The interplay of excitation and electroporation in nanosecond pulse stimulation. Bioelectrochemistry 2020; 136:107598. [PMID: 32711366 DOI: 10.1016/j.bioelechem.2020.107598] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/11/2022]
Abstract
Conventional electric stimuli of micro- and millisecond duration excite or activate cells at voltages 10-100 times below the electroporation threshold. This ratio is remarkably different for nanosecond electric pulses (nsEP), which caused excitation and activation only at or above the electroporation threshold in diverse cell lines, primary cardiomyocytes, neurons, and chromaffin cells. Depolarization to the excitation threshold often results from (or is assisted by) the loss of the resting membrane potential due to ion leaks across the membrane permeabilized by nsEP. Slow membrane resealing and the build-up of electroporation damages prevent repetitive excitation by nsEP. However, peripheral nerves and muscles are exempt from this rule and withstand multiple cycles of excitation by nsEP without the loss of function or signs of electroporation. We show that the damage-free excitation by nsEP may be enabled by the membrane charging time constant sufficiently large to (1) cap the peak transmembrane voltage during nsEP below the electroporation threshold, and (2) extend the post-nsEP depolarization long enough to activate voltage-gated ion channels. The low excitatory efficacy of nsEP compared to longer pulses makes them advantageous for medical applications where the neuromuscular excitation is an unwanted side effect, such as electroporation-based cancer and tissue ablation.
Collapse
Affiliation(s)
- Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
| |
Collapse
|
14
|
Cheng Y, Li H, Wang L, Li J, Kang W, Rao P, Zhou F, Wang X, Huang C. Optogenetic approaches for termination of ventricular tachyarrhythmias after myocardial infarction in rats in vivo. J Biophotonics 2020; 13:e202000003. [PMID: 32246523 DOI: 10.1002/jbio.202000003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
Cardiac optogenetics facilitates the painless manipulation of the heart with optical energy and was recently shown to terminate ventricular tachycardia (VT) in explanted mice heart. This study aimed to evaluate the optogenetic-based termination of induced VT under ischemia in an open-chest rat model and to develop an optimal, optical-manipulation procedure. VT was induced by burst stimulation after ligation of the left anterior descending coronary artery, and the termination effects of the optical manipulation, including electrical anti-tachycardia pacing (ATP) and spontaneous recovery, were tested. Among different multisegment optical modes, four repeated illuminations of 1000 ms in duration with 1-second interval at a 20-times intensity threshold on the right ventricle achieved the highest termination rate of 86.14% ± 4.145%, higher than that achieved by ATP and spontaneous termination. We demonstrated that optogenetic-based cardioversion is feasible and effective in vivo, with the underlying mechanism involving the light-triggered, ChR2-induced depolarization of the illuminated myocardium, in turn generating an excitation that disrupts the preexisting reentrant wave front.
Collapse
Affiliation(s)
- Yue Cheng
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Haitao Li
- Department of Cardiology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Long Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jianyi Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Wen Kang
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Panpan Rao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Fang Zhou
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
- Department of Cardiology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, People's Republic of China
- Cardiovascular Research Institute, Wuhan University, Wuhan, People's Republic of China
- Hubei Key Laboratory of Cardiology, Wuhan, People's Republic of China
| |
Collapse
|
15
|
Chiou YA, Cheng LK, Lin SF. Effects of high-frequency biphasic shocks on ventricular vulnerability and defibrillation outcomes through synchronized virtual electrode responses. PLoS One 2020; 15:e0232529. [PMID: 32357163 PMCID: PMC7194403 DOI: 10.1371/journal.pone.0232529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/16/2020] [Indexed: 11/19/2022] Open
Abstract
Electrical defibrillation is a well-established treatment for cardiac dysrhythmias. Studies have suggested that shock-induced spatial sawtooth patterns and virtual electrodes are responsible for defibrillation efficacy. We hypothesize that high-frequency shocks enhance defibrillation efficacy by generating temporal sawtooth patterns and using rapid virtual electrodes synchronized with shock frequency. High-speed optical mapping was performed on isolated rat hearts at 2000 frames/s. Two defibrillation electrodes were placed on opposite sides of the ventricles. An S1-S2 pacing protocol was used to induce ventricular tachyarrhythmia (VTA). High-frequency shocks of equal energy but varying frequencies of 125–1000 Hz were used to evaluate VTA vulnerability and defibrillation success rate. The 1000-Hz shock had the highest VTA induction rate in the shorter S1-S2 intervals (50 and 100 ms) and the highest VTA defibrillation rate (70%) among all frequencies. Temporal sawtooth patterns and synchronous shock-induced virtual electrode responses could be observed with frequencies of up to 1000 Hz. The improved defibrillation outcome with high-frequency shocks suggests a lower energy requirement than that of low-frequency shocks for successful ventricular defibrillation.
Collapse
Affiliation(s)
- Yu-An Chiou
- Department of Electrical and Computer Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Li-Kuan Cheng
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Shien-Fong Lin
- Department of Electrical and Computer Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan
- * E-mail:
| |
Collapse
|
16
|
Abstract
The purpose of this review article is to summarize our current understanding of the efficacy and safety of cardiac defibrillation with nanosecond shocks. Experiments in isolated hearts, using optical mapping of the electrical activity, have demonstrated that nanosecond shocks can defibrillate with lower energies than conventional millisecond shocks. Single defibrillation strength nanosecond shocks do not cause obvious damage, but repeated stimulation leads to deterioration of the hearts. In isolated myocytes, nanosecond pulses can also stimulate at lower energies than at longer pulses and cause less electroporation (propidium uptake). The mechanism is likely electroporation of the plasma membrane. Repeated stimulation leads to distorted calcium gradients.
Collapse
Affiliation(s)
- Johanna U Neuber
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia
| | - Frency Varghese
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia
| |
Collapse
|
17
|
Moreno A, Walton RD, Constantin M, Bernus O, Vigmond EJ, Bayer JD. Wide-area low-energy surface stimulation of large mammalian ventricular tissue. Sci Rep 2019; 9:15863. [PMID: 31676789 PMCID: PMC6825186 DOI: 10.1038/s41598-019-51364-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/30/2019] [Indexed: 11/09/2022] Open
Abstract
The epicardial and endocardial surfaces of the heart are attractive targets to administer antiarrhythmic electrotherapies. Electrically stimulating wide areas of the surfaces of small mammalian ventricles is straightforward given the relatively small scale of their myocardial dimensions compared to the tissue space constant and electrical field. However, it has yet to be proven for larger mammalian hearts with tissue properties and ventricular dimensions closer to humans. Our goal was to address the feasibility and impact of wide-area electrical stimulation on the ventricular surfaces of large mammalian hearts at different stimulus strengths. This was accomplished by placing long line electrodes on the ventricular surfaces of pig hearts that span wide areas, and activating them individually. Stimulus efficacy was assessed and compared between surfaces, and tissue viability was evaluated. Activation time was dependent on stimulation strength and location, achieving uniform linear stimulation at 9x threshold strength. Endocardial stimulation activated more tissue transmurally than epicardial stimulation, which could be considered a potential target for future cardiac electrotherapies. Overall, our results indicate that electrically stimulating wide areas of the ventricular surfaces of large mammals is achievable with line electrodes, minimal tissue damage, and energies under the human pain threshold (100 mJ).
Collapse
Affiliation(s)
- Angel Moreno
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université. Pessac, Bordeaux, France.,Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France
| | - Richard D Walton
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université. Pessac, Bordeaux, France.,Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Marion Constantin
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université. Pessac, Bordeaux, France.,Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Olivier Bernus
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université. Pessac, Bordeaux, France.,Centre de Recherche Cardio-Thoracique de Bordeaux, Université de Bordeaux, U1045, Bordeaux, France.,INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France
| | - Edward J Vigmond
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université. Pessac, Bordeaux, France.,Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France
| | - Jason D Bayer
- IHU-LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université. Pessac, Bordeaux, France. .,Centre National De La Recherche Scientifique, Institut de Mathématiques de Bordeaux, UMR5251, Bordeaux, France. .,L'Institut de Rythmologie et Modélisation Cardiaque (LIRYC), Hôpital Xavier Arnozan, Avenue du Haut Lévêque, 33604, Pessac, France.
| |
Collapse
|
18
|
Pakhomov AG, Xiao S, Novickij V, Casciola M, Semenov I, Mangalanathan U, Kim V, Zemlin C, Sozer E, Muratori C, Pakhomova ON. Excitation and electroporation by MHz bursts of nanosecond stimuli. Biochem Biophys Res Commun 2019; 518:759-64. [PMID: 31472962 DOI: 10.1016/j.bbrc.2019.08.133] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 08/23/2019] [Indexed: 12/16/2022]
Abstract
Intense nanosecond pulsed electric field (nsPEF) is a novel modality for cell activation and nanoelectroporation. Applications of nsPEF in research and therapy are hindered by a high electric field requirement, typically from 1 to over 50 kV/cm to elicit any bioeffects. We show how this requirement can be overcome by engaging temporal summation when pulses are compressed into high-rate bursts (up to several MHz). This approach was tested for excitation of ventricular cardiomyocytes and peripheral nerve fibers; for membrane electroporation of cardiomyocytes, CHO, and HEK cells; and for killing EL-4 cells. MHz compression of nsPEF bursts (100-1000 pulses) enables excitation at only 0.01-0.15 kV/cm and electroporation already at 0.4-0.6 kV/cm. Clear separation of excitation and electroporation thresholds allows for multiple excitation cycles without membrane disruption. The efficiency of nsPEF bursts increases with the duty cycle (by increasing either pulse duration or repetition rate) and with increasing the total time "on" (by increasing either pulse duration or number). For some endpoints, the efficiency of nsPEF bursts matches a single "long" pulse whose amplitude and duration equal the time-average amplitude and duration of the bursts. For other endpoints this rule is not valid, presumably because of nsPEF-specific bioeffects and/or possible modification of targets already during the burst. MHz compression of nsPEF bursts is a universal and efficient way to lower excitation thresholds and facilitate electroporation.
Collapse
|
19
|
Lamberti P, Compitiello M, Romeo S, Lamberti P, Compitiello M, Romeo S, Lamberti P, Romeo S, Compitiello M. ns Pulsed Electric Field-Induced Action Potentials in the Circuital Model of an Axon. IEEE Trans Nanobioscience 2019; 17:110-116. [PMID: 29870334 DOI: 10.1109/tnb.2018.2822840] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pulsed electric fields with duration in the sub- and ns time scale (nsPEFs) increase the permeability of cell membranes, enabling the transport of normally impermeant molecules into or out of the cell (electroporation). Such effect is associated to intracellular alterations and indicates nsPEFs as a new stimulus to modulate cell functions. In particular, studies dealing with the application of nsPEFs to excitable cells suggest their use for the stimulation/inhibition of cell excitation. In this paper, the circuital model per surface unit of the plasma membrane of an axon was developed to implement the Hodgkin and Huxley equations, describing the action potential activation process. For the first time, a power electronics circuital simulator was adopted. The model was first validated with conventional microsecond stimuli, and then it was employed to identify the conditions for cell excitation by nsPEFs. The results demonstrated the possibility of electrostimulation by nsPEFs at depolarization levels far below those required for inducing electroporation, and with ionic current dynamics similar to that induced by conventional stimuli, confirming recent experimental findings. Moreover, by using a power electronics tool, easier integration of the cell modeling with the design and optimization of pulse generation systems can be gained.
Collapse
|
20
|
Azarov JE, Semenov I, Casciola M, Pakhomov AG. Excitation of murine cardiac myocytes by nanosecond pulsed electric field. J Cardiovasc Electrophysiol 2019; 30:392-401. [PMID: 30582656 DOI: 10.1111/jce.13834] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 01/26/2023]
Abstract
INTRODUCTION Opening of voltage-gated sodium channels takes tens to hundreds of microseconds, and mechanisms of their opening by nanosecond pulsed electric field (nsPEF) stimuli remain elusive. This study was aimed at uncovering the mechanisms of how nsPEF elicits action potentials (APs) in cardiomyocytes. METHODS AND RESULTS Fluorescent imaging of optical APs (FluoVolt) and Ca2+ -transients (Fluo-4) was performed in enzymatically isolated murine ventricular cardiomyocytes stimulated by 200-nanosecond trapezoidal pulses. nsPEF stimulation evoked tetrodotoxin-sensitive APs accompanied or preceded by slow sustained depolarization (SSD) and, in most cells, by transient afterdepolarization waves. SSD threshold was lower than the AP threshold (1.26 ± 0.03 vs 1.34 ± 0.03 kV/cm, respectively, P < 0.001). Inhibition of l-type calcium and sodium-calcium exchanger currents reduced the SSD amplitude and increased the AP threshold ( P < 0.05). The threshold for Ca 2+ -transients (1.40 ± 0.04 kV/cm) was not significantly affected by a tetrodotoxin-verapamil cocktail, suggesting the activation of a Ca 2+ entry pathway independent from the opening of Na + or Ca 2+ voltage-gated channels. Removal of external Ca 2+ decreased the SSD amplitude ( P = 0.004) and blocked Ca 2+ -transients but not APs. The incidence of transient afterdepolarization waves was decreased by verapamil and by removal of external Ca 2+ ( P = 0.002). CONCLUSIONS The study established that nsPEF stimulation caused calcium entry into cardiac myocytes (including routes other than voltage-gated calcium channels) and SSD. Tetrodotoxin-sensitive APs were mediated by SSD, whose amplitude depended on the calcium entry. Plasma membrane electroporation was the most likely primary mechanism of SSD with additional contribution from l-type calcium and sodium-calcium exchanger currents.
Collapse
Affiliation(s)
- Jan E Azarov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia.,Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.,Department of Physiology, Medical Institute of Pitirim Sorokin Syktyvkar State University, Syktyvkar, Russia
| | - Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, Virginia
| |
Collapse
|
21
|
Hristov K, Mangalanathan U, Casciola M, Pakhomova ON, Pakhomov AG. Expression of voltage-gated calcium channels augments cell susceptibility to membrane disruption by nanosecond pulsed electric field. Biochim Biophys Acta Biomembr 2018; 1860:2175-83. [PMID: 30409513 DOI: 10.1016/j.bbamem.2018.08.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 12/15/2022]
Abstract
We compared membrane permeabilization by nanosecond pulsed electric field (nsPEF) in HEK293 cells with and without assembled CaV1.3 L-type voltage-gated calcium channel (VGCC). Individual cells were subjected to one 300-ns pulse at 0 (sham exposure); 1.4; 1.8; or 2.3 kV/cm, and membrane permeabilization was evaluated by measuring whole-cell currents and by optical monitoring of cytosolic Ca2+. nsPEF had either no effect (0 and 1.4 kV/cm), or caused a lasting (>80 s) increase in the membrane conductance in about 50% of cells (1.8 kV/cm), or in all cells (2.3 kV/cm). The conductance pathway opened by nsPEF showed strong inward rectification, with maximum conductance increase for the inward current at the most negative membrane potentials. Although these potentials were below the depolarization threshold for VGCC activation, the increase in conductance in cells which expressed VGCC (VGCC+ cells) was about twofold greater than in cells which did not (VGCC- cells). Among VGCC+ cells, the nsPEF-induced increase in membrane conductance showed a positive correlation with the amplitude of VGCC current measured in the same cells prior to nsPEF exposure. These findings demonstrate that the expression of VGCC makes cells more susceptible to membrane permeabilization by nsPEF. Time-lapse imaging of nsPEF-induced Ca2+ transients confirmed permeabilization by a single 300-ns pulse at 1.8 or 2.3 kV/cm, but not at 1.4 kV/cm, and the transients were expectedly larger in VGCC+ cells. However, it remains to be established whether larger transients reflected additional Ca2+ entry through VGCC, or were a result of more severe electropermeabilization of VGCC+ cells.
Collapse
|
22
|
Semenov I, Grigoryev S, Neuber JU, Zemlin CW, Pakhomova ON, Casciola M, Pakhomov AG. Excitation and injury of adult ventricular cardiomyocytes by nano- to millisecond electric shocks. Sci Rep 2018; 8:8233. [PMID: 29844431 PMCID: PMC5974370 DOI: 10.1038/s41598-018-26521-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Intense electric shocks of nanosecond (ns) duration can become a new modality for more efficient but safer defibrillation. We extended strength-duration curves for excitation of cardiomyocytes down to 200 ns, and compared electroporative damage by proportionally more intense shocks of different duration. Enzymatically isolated murine, rabbit, and swine adult ventricular cardiomyocytes (VCM) were loaded with a Ca2+ indicator Fluo-4 or Fluo-5N and subjected to shocks of increasing amplitude until a Ca2+ transient was optically detected. Then, the voltage was increased 5-fold, and the electric cell injury was quantified by the uptake of a membrane permeability marker dye, propidium iodide. We established that: (1) Stimuli down to 200-ns duration can elicit Ca2+ transients, although repeated ns shocks often evoke abnormal responses, (2) Stimulation thresholds expectedly increase as the shock duration decreases, similarly for VCMs from different species, (3) Stimulation threshold energy is minimal for the shortest shocks, (4) VCM orientation with respect to the electric field does not affect the threshold for ns shocks, and (5) The shortest shocks cause the least electroporation injury. These findings support further exploration of ns defibrillation, although abnormal response patterns to repetitive ns stimuli are of a concern and require mechanistic analysis.
Collapse
Affiliation(s)
- Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Sergey Grigoryev
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Johanna U Neuber
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.
| |
Collapse
|