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.

Action potential duration restitution and ventricular fibrillation due to rapid focal excitation

2002 ◽  
Vol 282 (5) ◽  
pp. H1915-H1923 ◽  
Author(s):  
Moshe Swissa ◽  
Zhilin Qu ◽  
Toshihiko Ohara ◽  
Moon-Hyoung Lee ◽  
Shien-Fong Lin ◽  
...  
Keyword(s):  
Ventricular Fibrillation ◽  
Action Potential ◽  
Action Potential Duration ◽  
Cardiac Tissue ◽  
Diacetyl Monoxime ◽  
Focal Excitation ◽  
Mean Cycle ◽  
Rapid Activation ◽  
Action Potential Duration Restitution ◽  
Wave Break

The focal source hypothesis of ventricular fibrillation (VF) posits that rapid activation from a focal source, rather than action potential duration (APD) restitution properties, is responsible for the maintenance of VF. We injected aconitine (100 μg) into normal isolated perfused swine right ventricles (RVs) stained with 4-{β-[2-(di- n-butylamino)-6-naphthyl]vinyl}pyridinium (di-4-ANEPPS) for optical mapping studies. Within 97 ± 163 s, aconitine induced ventricular tachycardia (VT) with a mean cycle length 268 ± 37 ms, which accelerated before converting to VF. Drugs that flatten the APD restitution slope, including diacetyl monoxime (10–20 mM, n = 6), bretylium (10–20 μg/ml, n = 3), and verapamil (2–4 μg/ml, n = 3), reversibly converted VF to VT in all cases. In two RVs, VF persisted despite of the excision of the aconitine site. Simulations in two-dimensional cardiac tissue showed that once VF was initiated, it remained sustained even after the “aconitine” site was eliminated. In this model of focal source VF, the VT-to-VF transition occurred due to a wave break outside the aconitine site, and drugs that flattened the APD restitution slope converted VF to VT despite continuous activation from aconitine site.

scholarly journals Theoretical Aspects of Resting-State Cardiomyocyte Communication for Multi-Nodal Nano-Actuator Pacemakers

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2792
Author(s):  
Pengfei Lu ◽  
Mladen Veletić ◽  
Jacob Bergsland ◽  
Ilangko Balasingham
Keyword(s):  
Action Potential ◽  
Resting State ◽  
Communication Channel ◽  
Potential Model ◽  
Signal Propagation ◽  
Cardiac Cells ◽  
The Body ◽  
Cardiac Muscle Cells ◽  
Leadless Pacemaker ◽  
Communication Technique

The heart consists of billions of cardiac muscle cells—cardiomyocytes—that work in a coordinated fashion to supply oxygen and nutrients to the body. Inter-connected specialized cardiomyocytes form signaling channels through which the electrical signals are propagated throughout the heart, controlling the heart’s beat to beat function of the other cardiac cells. In this paper, we study to what extent it is possible to use ordinary cardiomyocytes as communication channels between components of a recently proposed multi-nodal leadless pacemaker, to transmit data encoded in subthreshold membrane potentials. We analyze signal propagation in the cardiac infrastructure considering noise in the communication channel by performing numerical simulations based on the Luo-Rudy computational model. The Luo-Rudy model is an action potential model but describes the potential changes with time including membrane potential and action potential stages, separated by the thresholding mechanism. Demonstrating system performance, we show that cardiomyocytes can be used to establish an artificial communication system where data are reliably transmitted between 10 s of cells. The proposed subthreshold cardiac communication lays the foundation for a new intra-cardiac communication technique.

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.

Local Onset of Voltage and Calcium Alternans in the Heart

2011 ◽  
Author(s):  
Stephen D. McIntyre ◽  
Yoichiro Mori ◽  
Elena G. Tolkacheva
Keyword(s):  
Ventricular Fibrillation ◽  
Action Potential ◽  
Intracellular Calcium ◽  
Cardiac Myocytes ◽  
Cardiac Tissue ◽  
Potential Model ◽  
Cardiac Action Potential ◽  
2D Simulation ◽  
Cardiac Action ◽  
Electrical Alternans

A beat-to-beat variation in cardiac action potential durations (APD) is a phenomenon known as electrical alternans. Alternans desynchronizes depolarization, increases dispersion of refractoriness and creates a substrate for ventricular fibrillation. In the heart, APD alternans can be accompanied by alternans in intracellular calcium ([Ca2+]i) transients. Recently, we demonstrated experimentally that the onset of APD alternans in the heart is a local phenomenon that undergoes complex spatiotemporal dynamics as pacing rate increases. Moreover, the local onset of APD alternans can be predicted by measuring the restitution properties of periodically paced cardiac tissue. The purpose of this research is to investigate the interplay between local onsets of APD and [Ca2+]i alternans using 2D simulation of action potential model of cardiac myocytes.

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

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.

Simulation of the effects of moderate stimulation/inhibition of the β1-adrenergic signaling system and its components in mouse ventricular myocytes

2016 ◽  
Vol 310 (11) ◽  
pp. C844-C856 ◽  
Author(s):  
Mark Grinshpon ◽  
Vladimir E. Bondarenko
Keyword(s):  
Mathematical Model ◽  
Action Potential ◽  
Action Potential Duration ◽  
Ventricular Myocytes ◽  
Cardiac Cells ◽  
Protein Signaling ◽  
Signaling System ◽  
Adrenergic Signaling ◽  
Signaling Systems ◽  
Stimulation Of

The β1-adrenergic signaling system is one of the most important protein signaling systems in cardiac cells. It regulates cardiac action potential duration, intracellular Ca2+concentration ([Ca2+]i) transients, and contraction force. In this paper, a comprehensive experimentally based mathematical model of the β1-adrenergic signaling system for mouse ventricular myocytes is explored to simulate the effects of moderate stimulations of β1-adrenergic receptors (β1-ARs) on the action potential, Ca2+and Na+dynamics, as well as the effects of inhibition of protein kinase A (PKA) and phosphodiesterase of type 4 (PDE4). Simulation results show that the action potential prolongations reach saturating values at relatively small concentrations of isoproterenol (∼0.01 μM), while the [Ca2+]itransient amplitude saturates at significantly larger concentrations (∼0.1–1.0 μM). The differences in the response of Ca2+and Na+fluxes to moderate stimulation of β1-ARs are also observed. Sensitivity analysis of the mathematical model is performed and the model limitations are discussed. The investigated model reproduces most of the experimentally observed effects of moderate stimulation of β1-ARs, PKA, and PDE4 inhibition on the L-type Ca2+current, [Ca2+]itransients, and the sarcoplasmic reticulum Ca2+load and makes testable predictions for the action potential duration and [Ca2+]itransients as functions of isoproterenol concentration.

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.

Sign in / Sign up

Export Citation Format

Share Document