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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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2
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Hsieh YK, Wang MT, Wang CY, Chen CF, Ko YL, Huang WC. Recent advances in the diagnosis and management of acute myocardial infarction. J Chin Med Assoc 2023; 86:950-959. [PMID: 37801590 DOI: 10.1097/jcma.0000000000001001] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/08/2023] Open
Abstract
With the discovery of new biomarkers for the early detection of acute myocardial infarction (AMI), advancements in valid medication, and percutaneous coronary intervention (PCI), the overall prognosis of AMI has improved remarkably. Nevertheless, challenges remain which require more difficult work to overcome. Novel diagnostic and therapeutic techniques include new AMI biomarkers, hypothermia therapy, supersaturated oxygen (SSO 2 ) therapy, targeted anti-inflammatory therapy, targeted angiogenesis therapy, and stem cell therapy. With these novel methods, we believe that the infarction size after AMI will decrease, and myocardial injury-associated ventricular remodeling may be avoided. This review focuses on novel advances in the diagnosis and management of AMI.
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Affiliation(s)
- Yi-Keng Hsieh
- Department of Critical Care Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC
- Chang Gung Memorial Hospital, Taoyuan, Taiwan, ROC
- School of Medicine, National Yang Ming Chao Tung University, Taipei, Taiwan, ROC
| | - Mei-Tzu Wang
- Department of Critical Care Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC
- School of Medicine, National Yang Ming Chao Tung University, Taipei, Taiwan, ROC
| | - Chien-Ying Wang
- School of Medicine, National Yang Ming Chao Tung University, Taipei, Taiwan, ROC
- Department of Critical Care Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Division of Trauma, Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Exercise and Health Sciences, University of Taipei, Taipei, Taiwan, ROC
| | - Cheng-Fong Chen
- Department of Orthopaedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Surgery, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
- Department of Exercise and Health Sciences, University of Taipei, Taipei, Taiwan, ROC
| | - Yu-Ling Ko
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Wei-Chun Huang
- Department of Critical Care Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ROC
- Chang Gung Memorial Hospital, Taoyuan, Taiwan, ROC
- Department of Physical Therapy, Fooyin University, Kaohsiung, Taiwan, ROC
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3
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Rotors anchored by refractory islands drive torsades de pointes in an experimental model of electrical storm. Heart Rhythm 2022; 19:318-329. [PMID: 34678525 PMCID: PMC8810573 DOI: 10.1016/j.hrthm.2021.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND Electrical storm (ES) is a life-threatening emergency in patients at high risk of ventricular tachycardia/ventricular fibrillation (VF), but the pathophysiology and molecular basis are poorly understood. OBJECTIVE The purpose of this study was to explore the electrophysiological substrate for experimental ES. METHODS A model was created by inducing chronic complete atrioventricular block in defibrillator-implanted rabbits, which recapitulates QT prolongation, torsades des pointes (TdP), and VF episodes. RESULTS Optical mapping revealed island-like regions with action potential duration (APD) prolongation in the left ventricle, leading to increased spatial APD dispersion, in rabbits with ES (defined as ≥3 VF episodes/24 h). The maximum APD and its dispersion correlated with the total number of VF episodes in vivo. TdP was initiated by an ectopic beat that failed to enter the island and formed a reentrant wave and perpetuated by rotors whose centers swirled in the periphery of the island. Epinephrine exacerbated the island by prolonging APD and enhancing APD dispersion, which was less evident after late Na+ current blockade with 10 μM ranolazine. Nonsustained ventricular tachycardia in a non-ES rabbit heart with homogeneous APD prolongation resulted from multiple foci with an electrocardiographic morphology different from TdP driven by drifting rotors in ES rabbit hearts. The neuronal Na+-channel subunit NaV1.8 was upregulated in ES rabbit left ventricular tissues and expressed within the myocardium corresponding to the island location in optically mapped ES rabbit hearts. The NaV1.8 blocker A-803467 (10 mg/kg, intravenously) attenuated QT prolongation and suppressed epinephrine-evoked TdP. CONCLUSION A tissue island with enhanced refractoriness contributes to the generation of drifting rotors that underlies ES in this model. NaV1.8-mediated late Na+ current merits further investigation as a contributor to the substrate for ES.
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Majumder R, Mohamed Nazer AN, Panfilov AV, Bodenschatz E, Wang Y. Electrophysiological Characterization of Human Atria: The Understated Role of Temperature. Front Physiol 2021; 12:639149. [PMID: 34366877 PMCID: PMC8346027 DOI: 10.3389/fphys.2021.639149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
Ambient temperature has a profound influence on cellular electrophysiology through direct control over the gating mechanisms of different ion channels. In the heart, low temperature is known to favor prolongation of the action potential. However, not much is known about the influence of temperature on other important characterization parameters such as the resting membrane potential (RMP), excitability, morphology and characteristics of the action potential (AP), restitution properties, conduction velocity (CV) of signal propagation, etc. Here we present the first, detailed, systematic in silico study of the electrophysiological characterization of cardiomyocytes from different regions of the normal human atria, based on the effects of ambient temperature (5-50°C). We observe that RMP decreases with increasing temperature. At ~ 48°C, the cells lose their excitability. Our studies show that different parts of the atria react differently to the same changes in temperature. In tissue simulations a drop in temperature correlated positively with a decrease in CV, but the decrease was region-dependent, as expected. In this article we show how this heterogeneous response can provide an explanation for the development of a proarrhythmic substrate during mild hypothermia. We use the above concept to propose a treatment strategy for atrial fibrillation that involves severe hypothermia in specific regions of the heart for a duration of only ~ 200 ms.
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Affiliation(s)
- Rupamanjari Majumder
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | | | - Alexander V Panfilov
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov University, Moscow, Russia.,Department of Physics and Astronomy, Ghent University, Ghent, Belgium.,Laboratory of Computational Biology and Medicine, Ural Federal University, Yekaterinburg, Russia
| | - Eberhard Bodenschatz
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Laboratory of Atomic and Solid-State Physics and Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, United States
| | - Yong Wang
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
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5
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El Farissi M, Keulards DCJ, Zelis JM, van 't Veer M, Zimmermann FM, Pijls NHJ, Otterspoor LC. Hypothermia for Reduction of Myocardial Reperfusion Injury in Acute Myocardial Infarction: Closing the Translational Gap. Circ Cardiovasc Interv 2021; 14:e010326. [PMID: 34266310 DOI: 10.1161/circinterventions.120.010326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Myocardial reperfusion injury-triggered by an inevitable inflammatory response after reperfusion-may undo a considerable part of the myocardial salvage achieved through timely percutaneous coronary intervention in patients with acute myocardial infarction. Because infarct size is strongly correlated to mortality and risk of heart failure, the importance of endeavors for cardioprotective therapies to attenuate myocardial reperfusion injury and decrease infarct size remains undisputed. Myocardial reperfusion injury is the result of several complex nonlinear phenomena, and for a therapy to be effective, it should act on multiple targets involved in this injury. In this regard, hypothermia remains a promising treatment despite a number of negative randomized controlled trials in humans with acute myocardial infarction so far. To turn the tide for hypothermia in patients with acute myocardial infarction, sophisticated solutions for important limitations of systemic hypothermia should continue to be developed. In this review, we provide a comprehensive overview of the pathophysiology and clinical expression of myocardial reperfusion injury and discuss the current status and possible future of hypothermia for cardioprotection in patients with acute myocardial infarction.
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Affiliation(s)
- Mohamed El Farissi
- Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands
| | | | - Jo M Zelis
- Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands
| | - Marcel van 't Veer
- Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands
| | | | - Nico H J Pijls
- Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands
| | - Luuk C Otterspoor
- Department of Cardiology, Catharina Hospital, Eindhoven, the Netherlands
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6
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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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7
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Tomii N, Asano K, Seno H, Ashihara T, Sakuma I, Yamazaki M. Validation of Intraoperative Catheter Phase Mapping Using a Simultaneous Optical Measurement System in Rabbit Ventricular Myocardium. Circ J 2020; 84:609-615. [DOI: 10.1253/circj.cj-19-1020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Naoki Tomii
- Faculty of Medicine, The University of Tokyo
| | | | | | - Takashi Ashihara
- Information Technology and Management Center, Shiga University of Medical Science
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8
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Shibata N, Inada S, Nakazawa K, Tomii N, Yamazaki M, Seno H, Honjo H, Sakuma I. Mechanism of Electrical Defibrillation: Current Status and Future Perspective. ADVANCED BIOMEDICAL ENGINEERING 2020. [DOI: 10.14326/abe.9.125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Nitaro Shibata
- Department of Cardiology, Shinjuku Mitsui Building Clinic
| | - Shin Inada
- Faculty of Health Sciences, Morinomiya University of Medical Sciences
| | - Kazuo Nakazawa
- Faculty of Health Sciences, Morinomiya University of Medical Sciences
| | - Naoki Tomii
- Department of Bioengineering, The University of Tokyo
| | | | - Hiroshi Seno
- Department of Bioengineering, The University of Tokyo
| | - Haruo Honjo
- Research Institute of Environmental Medicine, Nagoya University
| | - Ichiro Sakuma
- Department of Bioengineering, The University of Tokyo
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9
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Malki G, Zlochiver S. Cardiac spiral wave drifting due to spatial temperature gradients - A numerical study. Med Eng Phys 2018; 61:69-80. [PMID: 30201284 DOI: 10.1016/j.medengphy.2018.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 06/16/2018] [Accepted: 08/26/2018] [Indexed: 01/07/2023]
Abstract
Cardiac rotors are believed to be a major driver source of persistent atrial fibrillation (AF), and their spatiotemporal characterization is essential for successful ablation procedures. However, electrograms guided ablation have not been proven to have benefit over empirical ablation thus far, and there is a strong need of improving the localization of cardiac arrhythmogenic targets for ablation. A new approach for characterize rotors is proposed that is based on induced spatial temperature gradients (STGs), and investigated by theoretical study using numerical simulations. We hypothesize that such gradients will cause rotor drifting due to induced spatial heterogeneity in excitability, so that rotors could be driven towards the ablating probe. Numerical simulations were conducted in single cell and 2D atrial models using AF remodeled kinetics. STGs were applied either linearly on the entire tissue or as a small local perturbation, and the major ion channel rate constants were adjusted following Arrhenius equation. In the AF-remodeled single cell, recovery time increased exponentially with decreasing temperatures, despite the marginal effect of temperature on the action potential duration. In 2D models, spiral waves drifted with drifting velocity components affected by both temperature gradient direction and the spiral wave rotation direction. Overall, spiral waves drifted towards the colder tissue region associated with global minimum of excitability. A local perturbation with a temperature of T = 28 °C was found optimal for spiral wave attraction for the studied conditions. This work provides a preliminary proof-of-concept for a potential prospective technique for rotor attraction. We envision that the insights from this study will be utilize in the future in the design of a new methodology for AF characterization and termination during ablation procedures.
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Affiliation(s)
- Guy Malki
- Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel
| | - Sharon Zlochiver
- Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel.
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10
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Tomii N, Yamazaki M, Arafune T, Kamiya K, Nakazawa K, Honjo H, Shibata N, Sakuma I. Interaction of phase singularities on the spiral wave tail: reconsideration of capturing the excitable gap. Am J Physiol Heart Circ Physiol 2018. [DOI: 10.1152/ajpheart.00558.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The action mechanism of stimulation toward spiral waves (SWs) owing to the complex excitation patterns that occur just after point stimulation has not yet been experimentally clarified. This study sought to test our hypothesis that the effect of capturing excitable gap of SWs by stimulation can also be explained as the interaction of original phase singularity (PS) and PSs induced by the stimulation on the wave tail (WT) of the original SW. Phase variance analysis was used to quantitatively analyze the postshock PS trajectories. In a two-dimensional subepicardial layer of Langendorff-perfused rabbit hearts, optical mapping was used to record the excitation pattern during stimulation. After a SW was induced by S1–S2 shock, single biphasic point stimulation S3 was applied. In 70 of the S1-S2-S3 stimulation episodes applied on 6 hearts, the original PS was clearly observed just before the S3 point stimulation in 37 episodes. Pairwise PSs were newly induced by the S3 in 20 episodes. The original PS collided with the newly induced PSs in 16 episodes; otherwise, they did not interact with the original PS. SW shift occurred most efficiently when the S3 shock was applied at the relative refractory period, and PS shifted in the direction of the WT. In conclusion, quantitative tracking of PS clarified that stimulation in desirable conditions induces pairwise PSs on WT and that the collision of PSs causes SW shift along the WT. The results of this study indicate the importance of the interaction of shock-induced excitation with the WT for effective stimulation. NEW & NOTEWORTHY The quantitative analysis of spiral wave dynamics during stimulation clarified the action mechanism of capturing the excitable gap, i.e., the induction of pairwise phase singularities on the wave tail and spiral wave shift along the wave tail as a result of these interactions. The importance of the wave tail for effective stimulation was revealed.
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Affiliation(s)
- Naoki Tomii
- Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | | | - Tatsuhiko Arafune
- Department of Science and Engineering, Tokyo Denki University, Tokyo, Japan
| | - Kaichiro Kamiya
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Kazuo Nakazawa
- National Cerebral and Cardiovascular Research Center, Osaka, Japan
| | - Haruo Honjo
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | | | - Ichiro Sakuma
- Department of Engineering, The University of Tokyo, Tokyo, Japan
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11
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Ogawa T, Honjo H, Yamazaki M, Kushiyama Y, Sakuma I, Kodama I, Kamiya K. Ranolazine Facilitates Termination of Ventricular Tachyarrhythmia Associated With Acute Myocardial Ischemia Through Suppression of Late I Na-Mediated Focal Activity. Circ J 2017; 81:1411-1428. [PMID: 28552884 DOI: 10.1253/circj.cj-17-0128] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Ventricular tachycardia/fibrillation (VT/VF) associated with acute myocardial ischemia is the most common cause of sudden cardiac death, but its underlying mechanisms are incompletely understood. It is hypothesized that late Na+current (INa) contributes to arrhythmogenic activity in ischemic myocardium.Methods and Results:Langendorff-perfused rabbit hearts with regional ischemia in ventricles were optically mapped. Perfusion with ranolazine (10 μmol/L), a selective inhibitor of lateINa, significantly reduced excitation frequency and facilitated termination of VT/VF induced after occlusion of the left main coronary trunk. The activation pattern during ischemic VT/VF was characterized by breakthrough-type excitations (BEs) from multiple origins, predominantly in the ischemic border zone (BZ) and occasional short-lived rotors. Ranolazine perfusion significantly reduced the incidence of BEs in the BZ. Rotors tended to decrease with progression of ischemia and disappeared after ranolazine perfusion. During constant pacing, ranolazine attenuated ischemia-induced shortening of action potentials in the BZ without affecting conduction velocity, probably due toIKrinhibition. In intact hearts without coronary occlusion, ranolazine (10 μmol/L) terminated aconitine-induced VT by inhibiting focal arrhythmogenic activity in the injection site. CONCLUSIONS LateINa-mediated focal arrhythmogenic activity plays important roles in the maintenance of ischemic VT/VF in isolated rabbit hearts. Suppression of lateINaby ranolazine may be a promising therapeutic strategy to reduce arrhythmic death during the acute phase of myocardial infarction.
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Affiliation(s)
- Takashi Ogawa
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University
| | - Haruo Honjo
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University
| | - Masatoshi Yamazaki
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University
| | - Yasunori Kushiyama
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University
| | - Ichiro Sakuma
- Graduate School of Engineering, The University of Tokyo
| | - Itsuo Kodama
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University
| | - Kaichiro Kamiya
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University
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12
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Tomii N, Yamazaki M, Arafune T, Honjo H, Shibata N, Sakuma I. Detection Algorithm of Phase Singularity Using Phase Variance Analysis for Epicardial Optical Mapping Data. IEEE Trans Biomed Eng 2016; 63:1795-1803. [DOI: 10.1109/tbme.2015.2502726] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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13
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Bai J, Wang K, Li Q, Yuan Y, Zhang H. Pro-arrhythmogenic effects of CACNA1C G1911R mutation in human ventricular tachycardia: insights from cardiac multi-scale models. Sci Rep 2016; 6:31262. [PMID: 27502440 PMCID: PMC4977499 DOI: 10.1038/srep31262] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 07/14/2016] [Indexed: 01/11/2023] Open
Abstract
Mutations in the CACNA1C gene are associated with ventricular tachycardia (VT). Although the CACNA1C mutations were well identified in patients with cardiac arrhythmias, mechanisms by which cardiac arrhythmias are generated in such genetic mutation conditions remain unclear. In this study, we identified a novel mechanism of VT resulted from enhanced repolarization dispersion which is a key factor for arrhythmias in the CACNA1C G1911R mutation using multi-scale computational models of the human ventricle. The increased calcium influx in the mutation prolonged action potential duration (APD), produced steepened action potential duration restitution (APDR) curves as well as augmented membrane potential differences among different cell types during repolarization, increasing transmural dispersion of repolarization (DOR) and the spatial and temporal heterogeneity of cardiac electrical activities. Consequentially, the vulnerability to unidirectional conduction block in response to a premature stimulus increased at tissue level in the G1911R mutation. The increased functional repolarization dispersion anchored reentrant excitation waves in tissue and organ models, facilitating the initiation and maintenance of VT due to less meandering rotor tip. Thus, the increased repolarization dispersion caused by the G1911R mutation is a primary factor that may primarily contribute to the genesis of cardiac arrhythmias in Timothy Syndrome.
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Affiliation(s)
- Jieyun Bai
- School of Computer Science and Technology, Harbin Institute Technology, Harbin, 150001, China
| | - Kuanquan Wang
- School of Computer Science and Technology, Harbin Institute Technology, Harbin, 150001, China
| | - Qince Li
- School of Computer Science and Technology, Harbin Institute Technology, Harbin, 150001, China
| | - Yongfeng Yuan
- School of Computer Science and Technology, Harbin Institute Technology, Harbin, 150001, China
| | - Henggui Zhang
- School of Computer Science and Technology, Harbin Institute Technology, Harbin, 150001, China
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK
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14
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Xu B, Jacquir S, Laurent G, Binczak S, Pont O, Yahia H. In vitroarrhythmia generation by mild hypothermia: a pitchfork bifurcation type process. Physiol Meas 2015; 36:579-94. [DOI: 10.1088/0967-3334/36/3/579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Defauw A, Vandersickel N, Dawyndt P, Panfilov AV. Small size ionic heterogeneities in the human heart can attract rotors. Am J Physiol Heart Circ Physiol 2014; 307:H1456-68. [PMID: 25217650 DOI: 10.1152/ajpheart.00410.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rotors occurring in the heart underlie the mechanisms of cardiac arrhythmias. Answering the question whether or not the location of rotors is related to local properties of cardiac tissue has important practical applications. This is because ablation of rotors has been shown to be an effective way to fight cardiac arrhythmias. In this study, we investigate, in silico, the dynamics of rotors in two-dimensional and in an anatomical model of human ventricles using a Ten Tusscher-Noble-Noble-Panfilov (TNNP) model for ventricular cells. We study the effect of small size ionic heterogeneities, similar to those measured experimentally. It is shown that such heterogeneities cannot only anchor, but can also attract, rotors rotating at a substantial distance from the heterogeneity. This attraction distance depends on the extent of the heterogeneities and can be as large as 5-6 cm in realistic conditions. We conclude that small size ionic heterogeneities can be preferred localization points for rotors and discuss their possible mechanism and value for applications.
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Affiliation(s)
- Arne Defauw
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Peter Dawyndt
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Ghent, Belgium; and
| | - Alexander V Panfilov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium; Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia
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16
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Bingen BO, Engels MC, Schalij MJ, Jangsangthong W, Neshati Z, Feola I, Ypey DL, Askar SFA, Panfilov AV, Pijnappels DA, de Vries AAF. Light-induced termination of spiral wave arrhythmias by optogenetic engineering of atrial cardiomyocytes. Cardiovasc Res 2014; 104:194-205. [PMID: 25082848 DOI: 10.1093/cvr/cvu179] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Atrial fibrillation (AF) is the most common cardiac arrhythmia and often involves reentrant electrical activation (e.g. spiral waves). Drug therapy for AF can have serious side effects including proarrhythmia, while electrical shock therapy is associated with discomfort and tissue damage. Hypothetically, forced expression and subsequent activation of light-gated cation channels in cardiomyocytes might deliver a depolarizing force sufficient for defibrillation, thereby circumventing the aforementioned drawbacks. We therefore investigated the feasibility of light-induced spiral wave termination through cardiac optogenetics. METHODS AND RESULTS Neonatal rat atrial cardiomyocyte monolayers were transduced with lentiviral vectors encoding light-activated Ca(2+)-translocating channelrhodopsin (CatCh; LV.CatCh∼eYFP↑) or eYFP (LV.eYFP↑) as control, and burst-paced to induce spiral waves rotating around functional cores. Effects of CatCh activation on reentry were investigated by optical and multi-electrode array (MEA) mapping. Western blot analyses and immunocytology confirmed transgene expression. Brief blue light pulses (10 ms/470 nm) triggered action potentials only in LV.CatCh∼eYFP↑-transduced cultures, confirming functional CatCh-mediated current. Prolonged light pulses (500 ms) resulted in reentry termination in 100% of LV.CatCh∼eYFP↑-transduced cultures (n = 31) vs. 0% of LV.eYFP↑-transduced cultures (n = 11). Here, CatCh activation caused uniform depolarization, thereby decreasing overall excitability (MEA peak-to-peak amplitude decreased 251.3 ± 217.1 vs. 9.2 ± 9.5 μV in controls). Consequently, functional coresize increased and phase singularities (PSs) drifted, leading to reentry termination by PS-PS or PS-boundary collisions. CONCLUSION This study shows that spiral waves in atrial cardiomyocyte monolayers can be terminated effectively by a light-induced depolarizing current, produced by the arrhythmogenic substrate itself, upon optogenetic engineering. These results provide proof-of-concept for shockless defibrillation.
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Affiliation(s)
- Brian O Bingen
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Marc C Engels
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Martin J Schalij
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Wanchana Jangsangthong
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Zeinab Neshati
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Iolanda Feola
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Dirk L Ypey
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Saïd F A Askar
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | | | - Daniël A Pijnappels
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
| | - Antoine A F de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Heart Lung Center Leiden, Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, the Netherlands
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Filippi S, Gizzi A, Cherubini C, Luther S, Fenton FH. Mechanistic insights into hypothermic ventricular fibrillation: the role of temperature and tissue size. Europace 2014; 16:424-34. [PMID: 24569897 PMCID: PMC3934849 DOI: 10.1093/europace/euu031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 01/27/2014] [Indexed: 12/26/2022] Open
Abstract
AIMS Hypothermia is well known to be pro-arrhythmic, yet it has beneficial effects as a resuscitation therapy and valuable during intracardiac surgeries. Therefore, we aim to study the mechanisms that induce fibrillation during hypothermia. A better understanding of the complex spatiotemporal dynamics of heart tissue as a function of temperature will be useful in managing the benefits and risks of hypothermia. METHODS AND RESULTS We perform two-dimensional numerical simulations by using a minimal model of cardiac action potential propagation fine-tuned on experimental measurements. The model includes thermal factors acting on the ionic currents and the gating variables to correctly reproduce experimentally recorded restitution curves at different temperatures. Simulations are implemented using WebGL, which allows long simulations to be performed as they run close to real time. We describe (i) why fibrillation is easier to induce at low temperatures, (ii) that there is a minimum size required for fibrillation that depends on temperature, (iii) why the frequency of fibrillation decreases with decreasing temperature, and (iv) that regional cooling may be an anti-arrhythmic therapy for small tissue sizes however it may be pro-arrhythmic for large tissue sizes. CONCLUSION Using a mathematical cardiac cell model, we are able to reproduce experimental observations, quantitative experimental results, and discuss possible mechanisms and implications of electrophysiological changes during hypothermia.
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Affiliation(s)
- Simonetta Filippi
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
- International Center for Relativistic Astrophysics—I.C.R.A, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
| | - Alessio Gizzi
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
- International Center for Relativistic Astrophysics—I.C.R.A, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
| | - Christian Cherubini
- Nonlinear Physics and Mathematical Modeling Laboratory, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
- International Center for Relativistic Astrophysics—I.C.R.A, University Campus Bio-Medico of Rome, Via A. del Portillo 21, I-00128 Rome, Italy
| | - Stefan Luther
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 Göttingen, Germany
| | - Flavio H. Fenton
- School of Physics, Georgia Institute of Technology, 837 State Street Atlanta, Atlanta, GA 30332, USA
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18
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Abstract
The objective of this article is to present a broad review of the role of cardiac electric rotors and their accompanying spiral waves in the mechanism of cardiac fibrillation. At the outset, we present a brief historical overview regarding reentry and then discuss the basic concepts and terminologies pertaining to rotors and their initiation. Thereafter, the intrinsic properties of rotors and spiral waves, including phase singularities, wavefront curvature, and dominant frequency maps, are discussed. The implications of rotor dynamics for the spatiotemporal organization of fibrillation, independent of the species being studied, are described next. The knowledge gained regarding the role of cardiac structure in the initiation or maintenance of rotors and the ionic bases of spiral waves in the past 2 decades, as well as the significance for drug therapy, is reviewed subsequently. We conclude by examining recent evidence suggesting that rotors are critical in sustaining both atrial and ventricular fibrillation in the human heart and its implications for treatment with radiofrequency ablation.
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Affiliation(s)
- Sandeep V Pandit
- Center for Arrhythmia Research, University of Michigan, NCRC, 2800 Plymouth Rd, Ann Arbor, MI 48109, USA
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19
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Fenton FH, Gizzi A, Cherubini C, Pomella N, Filippi S. Role of temperature on nonlinear cardiac dynamics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:042717. [PMID: 23679459 DOI: 10.1103/physreve.87.042717] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 12/19/2012] [Indexed: 06/02/2023]
Abstract
Thermal effects affecting spatiotemporal behavior of cardiac tissue are discussed by relating temperature variations to proarrhythmic dynamics in the heart. By introducing a thermoelectric coupling in a minimal model of cardiac tissue, we are able to reproduce experimentally measured dynamics obtained simultaneously from epicardial and endocardial canine right ventricles at different temperatures. A quantitative description of emergent proarrhythmic properties of restitution, conduction velocity, and alternans regimes as a function of temperature is presented. Complex discordant alternans patterns that enhance tissue dispersion consisting of one wave front and three wave backs are described in both simulations and experiments. Possible implications for model generalization are finally discussed.
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Affiliation(s)
- Flavio H Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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Atienza F, Martins RP, Jalife J. Translational research in atrial fibrillation: a quest for mechanistically based diagnosis and therapy. Circ Arrhythm Electrophysiol 2012; 5:1207-15. [PMID: 23022707 DOI: 10.1161/circep.111.970335] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Felipe Atienza
- Hospital General Universitario Gregorio Marañón, Madrid, Spain
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Takemoto Y, Takanari H, Honjo H, Ueda N, Harada M, Kato S, Yamazaki M, Sakuma I, Opthof T, Kodama I, Kamiya K. Inhibition of intercellular coupling stabilizes spiral-wave reentry, whereas enhancement of the coupling destabilizes the reentry in favor of early termination. Am J Physiol Heart Circ Physiol 2012; 303:H578-86. [PMID: 22707561 DOI: 10.1152/ajpheart.00355.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Spiral-wave (SW) reentry is a major organizing principle of ventricular tachycardia/fibrillation (VT/VF). We tested a hypothesis that pharmacological modification of gap junction (GJ) conductance affects the stability of SW reentry in a two-dimensional (2D) epicardial ventricular muscle layer prepared by endocardial cryoablation of Langendorff-perfused rabbit hearts. Action potential signals were recorded and analyzed by high-resolution optical mapping. Carbenoxolone (CBX; 30 μM) and rotigaptide (RG, 0.1 μM) were used to inhibit and enhance GJ coupling, respectively. CBX decreased the space constant (λ) by 36%, whereas RG increased it by 22-24% (n = 5; P < 0.01). During centrifugal propagation, there was a linear relationship between the wavefront curvature (κ) and local conduction velocity (LCV): LCV = LCV(0) - D·κ (D, diffusion coefficient; LCV(0), LCV at κ = 0). CBX decreased LCV(0) and D by 27 ± 3 and 57 ± 3%, respectively (n = 5; P < 0.01). RG increased LCV(0) and D by 18 ± 3 and 54 ± 5%, respectively (n = 5, P < 0.01). The regression lines with and without RG crossed, resulting in a paradoxical decrease of LCV with RG at κ > ~60 cm(-1). SW reentry induced after CBX was stable, and the incidence of sustained VTs (>30 s) increased from 38 ± 4 to 85 ± 4% after CBX (n = 18; P < 0.01). SW reentry induced after RG was characterized by decremental conduction near the rotation center, prominent drift and self-termination by collision with the anatomical boundaries, and the incidence of sustained VTs decreased from 40 ± 5 to 17 ± 6% after RG (n = 13; P < 0.05). These results suggest that decreased intercellular coupling stabilizes SW reentry in 2D cardiac muscle, whereas increased coupling facilitates its early self-termination.
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Affiliation(s)
- Yoshio Takemoto
- Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
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Kato S, Honjo H, Takemoto Y, Takanari H, Suzuki T, Okuno Y, Opthof T, Sakuma I, Inada S, Nakazawa K, Ashihara T, Kodama I, Kamiya K. Pharmacological Blockade of IKs Destabilizes Spiral-Wave Reentry Under β-Adrenergic Stimulation in Favor of Its Early Termination. J Pharmacol Sci 2012; 119:52-63. [DOI: 10.1254/jphs.12008fp] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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