VULNERABILITY TO REENTRY, AND DRIFT, STABILITY AND BREAKDOWN OF SPIRAL WAVES IN A LINEAR GRADIENT OF GK IN A LUO–RUDY 1 VIRTUAL VENTRICULAR TISSUE

2003 ◽  
Vol 13 (12) ◽  
pp. 3865-3871 ◽  
Author(s):  
O. V. ASLANIDI ◽  
R. H. CLAYTON ◽  
A. V. HOLDEN ◽  
H. K. PHILLIPS ◽  
R. J. WARD
Keyword(s):  
Action Potential ◽  
Velocity Component ◽  
Action Potential Duration ◽  
Cardiac Tissue ◽  
Spiral Wave ◽  
Spiral Waves ◽  
Linear Gradient ◽  
Wave Solutions ◽  
Ventricular Tissue ◽  
Vulnerable Window

The vulnerable window in a heterogeneous virtual LRl cardiac tissue, with a linear gradient in GK, is wider when following propagation down the gradient, towards tissue with longer action potential duration, than when following propagation up the gradient. Spiral wave solutions in a uniform linear gradient in GK drift, with a velocity component along the gradient of the order of mm/s, towards tissue with a longer APD.

A computationally efficient electrophysiological model of human ventricular cells

2002 ◽  
Vol 282 (6) ◽  
pp. H2296-H2308 ◽  
Author(s):  
O. Bernus ◽  
R. Wilders ◽  
C. W. Zemlin ◽  
H. Verschelde ◽  
A. V. Panfilov
Keyword(s):  
Action Potential ◽  
Cardiac Tissue ◽  
Spiral Wave ◽  
Ionic Currents ◽  
Average Frequency ◽  
Computationally Efficient ◽  
Variable Model ◽  
Potential Shape ◽  
Ventricular Cells ◽  
Ventricular Tissue

Recent experimental and theoretical results have stressed the importance of modeling studies of reentrant arrhythmias in cardiac tissue and at the whole heart level. We introduce a six-variable model obtained by a reformulation of the Priebe-Beuckelmann model of a single human ventricular cell. The reformulated model is 4.9 times faster for numerical computations and it is more stable than the original model. It retains the action potential shape at various frequencies, restitution of action potential duration, and restitution of conduction velocity. We were able to reproduce the main properties of epicardial, endocardial, and M cells by modifying selected ionic currents. We performed a simulation study of spiral wave behavior in a two-dimensional sheet of human ventricular tissue and showed that spiral waves have a frequency of 3.3 Hz and a linear core of ∼50-mm diameter that rotates with an average frequency of 0.62 rad/s. Simulation results agreed with experimental data. In conclusion, the proposed model is suitable for efficient and accurate studies of reentrant phenomena in human ventricular tissue.

Cardiac electrical restitution properties and stability of reentrant spiral waves: a simulation study

1999 ◽  
Vol 276 (1) ◽  
pp. H269-H283 ◽  
Author(s):  
Zhilin Qu ◽  
James N. Weiss ◽  
Alan Garfinkel
Keyword(s):  
Action Potential ◽  
Antiarrhythmic Drugs ◽  
Cardiac Tissue ◽  
Potential Model ◽  
Spiral Wave ◽  
Spiral Waves ◽  
Two Dimensional ◽  
Recovery From Inactivation ◽  
Main Determinants ◽  
The Stability

Spiral wave breakup is a proposed mechanism underlying the transition from ventricular tachycardia to fibrillation. We examined the importance of the restitution of action potential duration (APD) and of conduction velocity (CV) to the stability of spiral wave reentry in a two-dimensional sheet of simulated cardiac tissue. The Luo-Rudy ventricular action potential model was modified to eliminate its restitution properties, which are caused by deactivation or recovery from inactivation of K+, Ca2+, and Na+ currents ( I K, I Ca, and I Na, respectively). In this model, we find that 1) restitution of I Ca and I Na are the main determinants of the steepness of APD restitution; 2) for promoting spiral breakup, the range of diastolic intervals over which the APD restitution slope is steep is more important than the maximum steepness; 3) CV restitution promotes spiral wave breakup independently of APD restitution; and 4) “defibrillation” of multiple spiral wave reentry is most effectively achieved by combining an antifibrillatory intervention based on altering restitution with an antitachycardia intervention. These findings suggest a novel paradigm for developing effective antiarrhythmic drugs.

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.

Electrophysiological heterogeneity and stability of reentry in simulated cardiac tissue

2001 ◽  
Vol 280 (2) ◽  
pp. H535-H545 ◽  
Author(s):  
Fagen Xie ◽  
Zhilin Qu ◽  
Alan Garfinkel ◽  
James N. Weiss
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Cardiac Tissue ◽  
Potential Model ◽  
Dynamic Instability ◽  
Spatial Scales ◽  
Cardiac Cells ◽  
Dynamic Factors ◽  
Cardiac Model ◽  
Wave Break

Generation of wave break is a characteristic feature of cardiac fibrillation. In this study, we investigated how dynamic factors and fixed electrophysiological heterogeneity interact to promote wave break in simulated two-dimensional cardiac tissue, by using the Luo-Rudy (LR1) ventricular action potential model. The degree of dynamic instability of the action potential model was controlled by varying the maximal amplitude of the slow inward Ca2+ current to produce spiral waves in homogeneous tissue that were either nearly stable, meandering, hypermeandering, or in breakup regimes. Fixed electrophysiological heterogeneity was modeled by randomly varying action potential duration over different spatial scales to create dispersion of refractoriness. We found that the degree of dispersion of refractoriness required to induce wave break decreased markedly as dynamic instability of the cardiac model increased. These findings suggest that reducing the dynamic instability of cardiac cells by interventions, such as decreasing the steepness of action potential duration restitution, may still have merit as an antifibrillatory strategy.

scholarly journals Action Potential Duration Maps in Homogeneous Cardiac Ventricular Tissue Slices are Independent of Changes in Stimulation Site

2012 ◽  
Vol 102 (3) ◽  
pp. 543a-544a
Author(s):  
Ken Wang ◽  
Peter Lee ◽  
David Gavaghan ◽  
Peter Kohl ◽  
Christian Bollensdorff
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Stimulation Site ◽  
Tissue Slices ◽  
Ventricular Tissue

Comments on “A model for human ventricular tissue”

2005 ◽  
Vol 288 (1) ◽  
pp. H453-H453
Author(s):  
Leonid Livshitz ◽  
Keith Decker ◽  
Gregory Faber ◽  
Thomas O'Hara ◽  
Jonathan Silva ◽  
...  
Keyword(s):  
Action Potential ◽  
Large Scale ◽  
Spiral Wave ◽  
Alternative Methods ◽  
Delayed Rectifier ◽  
Recent Experimental Data ◽  
M Cell ◽  
Ventricular Cells ◽  
Ventricular Tissue ◽  
Reentrant Arrhythmias

The experimental and clinical possibilities for studying cardiac arrhythmias in human ventricular myocardium are very limited. Therefore, the use of alternative methods such as computer simulations is of great importance. In this article we introduce a mathematical model of the action potential of human ventricular cells that, while including a high level of electrophysiological detail, is computationally cost-effective enough to be applied in large-scale spatial simulations for the study of reentrant arrhythmias. The model is based on recent experimental data on most of the major ionic currents: the fast sodium, L-type calcium, transient outward, rapid and slow delayed rectifier, and inward rectifier currents. The model includes a basic calcium dynamics, allowing for the realistic modeling of calcium transients, calcium current inactivation, and the contraction staircase. We are able to reproduce human epicardial, endocardial, and M cell action potentials and show that differences can be explained by differences in the transient outward and slow delayed rectifier currents. Our model reproduces the experimentally observed data on action potential duration restitution, which is an important characteristic for reentrant arrhythmias. The conduction velocity restitution of our model is broader than in other models and agrees better with available data. Finally, we model the dynamics of spiral wave rotation in a two-dimensional sheet of human ventricular tissue and show that the spiral wave follows a complex meandering pattern and has a period of 265 ms. We conclude that the proposed model reproduces a variety of electrophysiological behaviors and provides a basis for studies of reentrant arrhythmias in human ventricular tissue. Comments on “A model for human ventricular tissue” by K. H. W. J. ten Tusscher et al.

Action potential morphology heterogeneity in the atrium and its effect on atrial reentry: a two-dimensional and quasi-three-dimensional study

2006 ◽  
Vol 364 (1843) ◽  
pp. 1349-1366 ◽  
Author(s):  
Samuel R Kuo ◽  
Natalia A Trayanova
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Three Dimensional ◽  
Spiral Wave ◽  
Spiral Waves ◽  
Two Dimensional ◽  
Crista Terminalis ◽  
Wave Dynamics ◽  
Continuous Surface ◽  
The Right

Atrial fibrillation (AF) is believed to be perpetuated by recirculating spiral waves. Atrial structures are often characterized with action potentials of varying morphologies; however, the role of the structure-dependent atrial electrophysiological heterogeneity in spiral wave behaviour is not well understood. The purpose of this study is to determine the effect of action potential morphology heterogeneity associated with the major atrial structures in spiral wave maintenance. The present study also focuses on how this effect is further modulated by the presence of the inherent periodicity in atrial structure. The goals of the study are achieved through the simulation of electrical behaviour in a two-dimensional atrial tissue model that incorporates the representation of action potentials in various structurally distinct regions in the right atrium. Periodic boundary conditions are then imposed to form a cylinder (quasi three-dimensional), thus allowing exploration of the additional effect of structure periodicity on spiral wave behaviour. Transmembrane potential maps and phase singularity traces are analysed to determine effects on spiral wave behaviour. Results demonstrate that the prolonged refractoriness of the crista terminalis (CT) affects the pattern of spiral wave reentry, while the variation in action potential morphology of the other structures does not. The CT anchors the spiral waves, preventing them from drifting away. Spiral wave dynamics is altered when the ends of the sheet are spliced together to form a cylinder. The main effect of the continuous surface is the generation of secondary spiral waves which influences the primary rotors. The interaction of the primary and secondary spiral waves decreased as cylinder diameter increased.

scholarly journals Action Potential Duration Heterogeneity of Cardiac Tissue Can Be Evaluated from Cell Properties Using Gaussian Green's Function Approach

PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e79607 ◽  
Author(s):  
Arne Defauw ◽  
Ivan V. Kazbanov ◽  
Hans Dierckx ◽  
Peter Dawyndt ◽  
Alexander V. Panfilov
Keyword(s):  
Action Potential ◽  
Green’S Function ◽  
Green's Function ◽  
Action Potential Duration ◽  
Cardiac Tissue ◽  
Function Approach

Anisotropic repolarization in ventricular tissue

1997 ◽  
Vol 272 (1) ◽  
pp. H107-H113 ◽  
Author(s):  
M. Gotoh ◽  
T. Uchida ◽  
W. Fan ◽  
M. C. Fishbein ◽  
H. S. Karagueuzian ◽  
...  
Keyword(s):  
Action Potential ◽  
Fiber Orientation ◽  
Action Potential Duration ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
Stimulation Site ◽  
Recording Site ◽  
Myocardial Fiber ◽  
Ventricular Tissue ◽  
Cycle Lengths

Extracellular recording and stimulation techniques have been used to demonstrate that the effective refractory period of epicardial ventricular cells is significantly influenced by the sequence of activation. Whether myocardial fiber orientation is also important in determining the repolarization process is unclear. To determine the importance of fiber orientation on the repolarization process, we studied 12 blocks of pig right ventricular tissue in vitro. The size of each tissue block was 30 x 30 x 2 mm. Transmembrane action potentials were recorded, and effective refractory periods were measured from the preparation's epicardial surface, which showed nearly uniform fiber orientation. Tissues were paced at 500- and 1,000-ms cycle lengths. Sequential recordings were made at 1, 4, 7, 10, 13, and 16 mm from the stimulation site along and across the fibers. The results show that propagation of depolarization was much slower in the transverse direction than in the longitudinal direction. In the transverse direction, action potential duration was longest at the closest observation point, i.e., 1 mm from the stimulation, site (188 +/- 14 and 267 +/- 18 ms for 500- and 1,000-ms pacing cycle lengths, respectively). Action potential duration progressively shortened as the recording site was moved farther from the stimulation site (P < 0.001). The action potential duration 16 mm from the stimulation site was 165 +/- 11 and 247 +/- 12 ms for 500- and 1,000-ms pacing cycle lengths, respectively. In contrast, the action potential duration in the longitudinal direction did not change as the distance between the recording site and stimulation site increased. We conclude that, at physiological temperature and pacing cycle lengths, sequence of activation significantly influenced action potential duration when the propagation of activation was transverse to myocardial fiber orientation. When activation propagated parallel to fiber orientation, there was little or no change of action potential duration as distance increased.

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