Reentrant excitation in an analog-digital hybrid circuit model of cardiac tissue

2011 ◽  
Vol 21 (2) ◽  
pp. 023121 ◽  
Author(s):  
Farhanahani Mahmud ◽  
Naruhiro Shiozawa ◽  
Masaaki Makikawa ◽  
Taishin Nomura
Keyword(s):  
Cardiac Tissue ◽  
Circuit Model ◽  
Reentrant Excitation ◽  
Hybrid Circuit

scholarly journals A simple hybrid circuit model for folded waveguide structures

IVEC 2012 ◽  
2012 ◽  
Author(s):  
Thomas M. Antonsen ◽  
David Chernin ◽  
Alexander Vlasov ◽  
Igor Chernyavskiy ◽  
Khanh Nguyen ◽  
...  
Keyword(s):  
Circuit Model ◽  
Folded Waveguide ◽  
Hybrid Circuit

Reentry in heterogeneous cardiac tissue described by the Luo-Rudy ventricular action potential model

2003 ◽  
Vol 284 (2) ◽  
pp. H542-H548 ◽  
Author(s):  
K. H. W. J. Ten Tusscher ◽  
A. V. Panfilov
Keyword(s):  
Action Potential ◽  
Cardiac Tissue ◽  
Potential Model ◽  
Phase 1 ◽  
Spiral Wave ◽  
Spiral Waves ◽  
Local Current ◽  
Gradient Component ◽  
Reentrant Excitation ◽  
Ventricular Action Potential

Heterogeneity of cardiac tissue is an important factor determining the initiation and dynamics of cardiac arrhythmias. In this paper, we studied the effects of gradients of electrophysiological heterogeneity on reentrant excitation patterns using computer simulations. We investigated the dynamics of spiral waves in a two-dimensional sheet of cardiac tissue described by the Luo-Rudy phase 1 (LR1) ventricular action potential model. A gradient of action potential duration (APD) was imposed by gradually varying the local current density of K+ current or inward rectifying K+ current along one axis of the tissue sheet. We show that a gradient of APD resulted in spiral wave drift. This drift consisted of two components. The longitudinal (along the gradient) component was always directed toward regions of longer spiral wave period. The transverse (perpendicular to the gradient) component had a direction dependent on the direction of rotation of the spiral wave. We estimated the velocity of the drift as a function of the magnitude of the gradient and discuss its implications.

Theory of reentrant excitation in a ring of cardiac tissue

1992 ◽  
Vol 56 (1) ◽  
pp. 84-106 ◽  
Author(s):  
Hiroyuki Ito ◽  
Leon Glass
Keyword(s):  
Cardiac Tissue ◽  
Reentrant Excitation

Cytopathology of Cardiac Tissue from Daunomycin-Treated Mice

1971 ◽  
Vol 29 ◽  
pp. 550-551
Author(s):  
Robert H. Liss ◽  
Frances A. Cotton
Keyword(s):  
Cardiac Tissue ◽  
Cardiac Toxicity ◽  
Drug Distribution ◽  
Personal Communication ◽  
Intravenous Dose ◽  
Single Intravenous Dose ◽  
Physiologic Saline ◽  
Histopathologic Changes ◽  
Distribution Studies ◽  
Lung And Kidney

Daunomycin, an antibiotic used in the clinical management of acute leukemia, produces a delayed, lethal cardiac toxicity. The lethality is dose and schedule dependent; histopathologic changes induced by the drug have been described in heart, lung, and kidney from hamsters in both single and multiple dose studies. Mice given a single intravenous dose of daunomycin (10 mg/kg) die 6-7 days later. Drug distribution studies indicate that the rodents excrete most of a single dose of the drug as daunomycin and metabolite within 48 hours after dosage (M. A. Asbell, personal communication).Myocardium from the ventricles of 6 moribund BDF1 mice which had received a single intravenous dose of daunomycin (10 mg/kg), and from controls dosed with physiologic saline, was fixed in glutaraldehyde and prepared for electron microscopy.

Iron storage sites in the myocardium as revealed by cytohistochemistry

1988 ◽  
Vol 46 ◽  
pp. 394-395
Author(s):  
M. Ashraf ◽  
F. Thompson ◽  
S. Miki ◽  
P. Srivastava
Keyword(s):  
Cardiac Tissue ◽  
Coronary Perfusion ◽  
Intracellular Iron ◽  
Ether Anesthesia ◽  
Intense Staining ◽  
Iron Storage ◽  
Thin Sections ◽  
Rat Hearts ◽  
Cacodylate Buffer ◽  
Made In

Iron is believed to play an important role in the pathogenesis of ischemic injury. However, the sources of intracellular iron in myocytes are not yet defined. In this study we have attempted to localize iron at various cellular sites of the cardiac tissue with the ferrocyanide technique.Rat hearts were excised under ether anesthesia. They were fixed with coronary perfusion with 3% buffered glutaraldehyde made in 0.1 M cacodylate buffer pH 7.3. Sections, 60 μm in thickness, were cut on a vibratome and were incubated in the medium containing 500 mg of potassium ferrocyanide in 49.5 ml H2O and 0.5 ml concentrated HC1 for 30 minutes at room temperature. Following rinses in the buffer, tissues were dehydrated in ethanol and embedded in Spurr medium.The examination of thin sections revealed intense staining or reaction product in peroxisomes (Fig. 1).

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