scholarly journals Induced drift of scroll waves in the Aliev–Panfilov model and in an axisymmetric heart left ventricle

2020 ◽  
Vol 35 (5) ◽  
pp. 273-283 ◽  
Author(s):  
Sergei F. Pravdin ◽  
Timofei I. Epanchintsev ◽  
Timur V. Nezlobinskii ◽  
Alexander V. Panfilov
Keyword(s):  
Left Ventricle ◽  
Low Voltage ◽  
Three Dimensional ◽  
Spiral Wave ◽  
Spiral Waves ◽  
High Frequency Stimulation ◽  
Two Dimensional ◽  
Anatomical Model ◽  
Paroxysmal Tachycardia ◽  
Scroll Waves

AbstractThe low-voltage cardioversion-defibrillation is a modern sparing electrotherapy method for such dangerous heart arrhythmias as paroxysmal tachycardia and fibrillation. In an excitable medium, such arrhythmias relate to appearance of spiral waves of electrical excitation, and the spiral waves are superseded to the electric boundary of the medium in the process of treatment due to high-frequency stimulation from the electrode. In this paper we consider the Aliev–Panfilov myocardial model, which provides a positive tension of three-dimensional scroll waves, and an axisymmetric model of the left ventricle of the human heart. Two relations of anisotropy are considered, namely, isotropy and physiological anisotropy. The periods of stimulation with an apical electrode are found so that the electrode successfully entrains its rhythm in the medium, the spiral wave is superseded to the base of the ventricle, and disappears. The results are compared in two-dimensional and three-dimensional media. The intervals of effective stimulation periods are sufficiently close to each other in the two-dimensional case and in the anatomical model. However, the use of the anatomical model is essential in determination of the time of superseding.

THREE-DIMENSIONAL ASPECTS OF RE-ENTRY IN EXPERIMENTAL AND NUMERICAL MODELS OF VENTRICULAR FIBRILLATION

1999 ◽  
Vol 09 (04) ◽  
pp. 695-704 ◽  
Author(s):  
V. N. BIKTASHEV ◽  
A. V. HOLDEN ◽  
S. F. MIRONOV ◽  
A. M. PERTSOV ◽  
A. V. ZAITSEV
Keyword(s):  
Ventricular Fibrillation ◽  
Numerical Simulations ◽  
Numerical Models ◽  
Three Dimensional ◽  
Spiral Waves ◽  
Excitable Media ◽  
Ventricular Wall ◽  
Two Dimensional ◽  
Key Features ◽  
Scroll Waves

Ventricular fibrillation is believed to be produced by the breakdown of re-entrant propagation waves of excitation into multiple re-entrant sources. These re-entrant waves may be idealized as spiral waves in two-dimensional, and scroll waves in three-dimensional excitable media. Optically monitored, simultaneously recorded endocardial and epicardial patterns of activation on the ventricular wall do not always show spiral waves. We show that numerical simulations, even with a simple homogeneous excitable medium, can reproduce the key features of the simultaneous endo- and epicardial visualizations of propagating activity, and so these recordings may be interpreted in terms of scroll waves within the ventricular wall.

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 LOCALIZATION OF RESPONSE FUNCTIONS OF SPIRAL WAVES IN THE FITZHUGH–NAGUMO SYSTEM

2006 ◽  
Vol 16 (05) ◽  
pp. 1547-1555 ◽  
Author(s):  
I. V. BIKTASHEVA ◽  
A. V. HOLDEN ◽  
V. N. BIKTASHEV
Keyword(s):  
External Force ◽  
Wave Solution ◽  
Spiral Wave ◽  
Spiral Waves ◽  
Two Dimensional ◽  
Response Functions ◽  
Space And Time ◽  
Wave Drift ◽  
Linearized Problem ◽  
Small Periodic

Dynamics of spiral waves in perturbed, e.g. slightly inhomogeneous or subject to a small periodic external force, two-dimensional autowave media can be described asymptotically in terms of Aristotelean dynamics, so that the velocities of the spiral wave drift in space and time are proportional to the forces caused by the perturbation. The forces are defined as a convolution of the perturbation with the spirals Response Functions, which are eigenfunctions of the adjoint linearized problem. In this paper we find numerically the Response Functions of a spiral wave solution in the classic excitable FitzHugh–Nagumo model, and show that they are effectively localized in the vicinity of the spiral core.

scholarly journals Spiral waves within a bistability parameter region of an excitable medium

2022 ◽  
Author(s):  
Vladimir Zykov ◽  
Eberhard Bodenschatz
Keyword(s):  
Initial Conditions ◽  
Three Dimensional ◽  
Spiral Wave ◽  
Gradient Flow ◽  
Spiral Waves ◽  
Excitable Medium ◽  
Excitable Media ◽  
Circular Trajectory ◽  
Parameter Region ◽  
Scroll Wave

Abstract Spiral waves are a well-known and intensively studied dynamic phenomenon in excitable media of various types. Most studies have considered an excitable medium with a single stable resting state. However, spiral waves can be maintained in an excitable medium with bistability. Our calculations, performed using the widely used Barkley model, clearly show that spiral waves in the bistability region exhibit unique properties. For example, a spiral wave can either rotate around a core that is in an unexcited state, or the tip of the spiral wave describes a circular trajectory located inside an excited region. The boundaries of the parameter regions with positive and "negative" cores have been defined numerically and analytically evaluated. It is also shown that the creation of a positive or "negative" core may depend on the initial conditions, which leads to hysteresis of spiral waves. In addition, the influence of gradient flow on the dynamics of the spiral wave, which is related to the tension of the scroll wave filaments in a three-dimensional medium, is studied.

Three-Dimensional ROI-Based Quantification of Stress/Rest 201TI Myocardial SPECT: Presentation of Method

1986 ◽  
Vol 25 (04) ◽  
pp. 128-133 ◽  
Author(s):  
U. Büll ◽  
E. Kleinhans ◽  
H. Stirner
Keyword(s):  
Left Ventricle ◽  
Three Dimensional ◽  
Regions Of Interest ◽  
Short Axis ◽  
Myocardial Spect ◽  
Two Dimensional ◽  
Semiautomated Method ◽  
Oblique Slices

A semiautomated method for three-dimensional quantification of stress/rest 201TI myocardial SPECT of the left ventricle (LV) is introduced. A total of 33 ringsegment-shaped regions of interest (ROIs) are distributed over 6 oblique (short axis cuts) double-slices (thickness 1.3 cm) from LV apex to base, commencing with 1 ROI for the apex up to 8 ROIs for the base (1-4-4-8-8-8). Within the last two double slices an additional adjacent ROI is automatically placed in the upper right quadrant to observe lung Tl-uptake. Correspondence of slices for exercise and rest is achieved by adjusting the long axis outlines rebuilt from summed profiles of 15 oblique slices of each examination. Calculated numeric arrays of the extracted parameters (vitality, washout and redistribution) are “displayed in a target-like two-dimensional polar fashion.

Comparison of biplane manual, automated volumetric and MRI methods for assessment of left ventricle volumes and function in a series of three left ventricle non-compaction patients

2021 ◽  
Author(s):  
Katarzyna Justyna Pigon ◽  
Edyta Radzik ◽  
Krystyna Krzemień-Wolska ◽  
Brygida Przywara-Chowaniec ◽  
Ewa Nowalany-Kozielska ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Speckle Tracking ◽  
Three Dimensional ◽  
Golden Rule ◽  
Ventricular Myocardium ◽  
Two Dimensional ◽  
Prognostic Information ◽  
Dimensional Echocardiography ◽  
Three Dimensional Echocardiography ◽  
And Function

Abstract Background Non-compaction of the ventricular myocardium (LVNC) is a rare genetically determined heart defect. The disease is most frequently detected during accidental echocardiography. There is no golden rule examination for LVNC diagnosis. In our study, we aimed to compare the measurements of the left ventricle volumes and function obtained with the two-dimensional, and three-dimensional echo based on the results from MR imaging in a series of three left ventricle non-compaction cardiomyopathy patients. Case presentation Patients’ age was 43–53 years. Two patients presented with congestive heart failure, third patient presented with ventricular arrhythmia. The proportion of thickness of non-compacted to compacted layers ranged from 2.3 to 3.6. Three-dimensional echo has revealed substantially higher end-diastolic and end-systolic volumes in comparison to two-dimensional echo, yet not as high as assessed in magnetic resonance imaging. Speckle tracking revealed reduced global longitudinal, radial, and circumferential strain, even in the patients with normal left ventricle function. Conclusion Real-time three-dimensional echocardiography with automated left ventricle analysis offers more information on the assessment of left ventricle in patients with left ventricle non-compaction in comparison to two-dimensional echocardiography. Speckle tracking analysis may add prognostic information in this specific group of patients.

scholarly journals Overdrive pacing of spiral waves in a model of human ventricular tissue

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sergei F. Pravdin ◽  
Timofei I. Epanchintsev ◽  
Alexander V. Panfilov
Keyword(s):  
Cardiac Arrhythmias ◽  
Cardiac Tissue ◽  
Low Voltage ◽  
Spiral Waves ◽  
High Frequency Stimulation ◽  
In Silico Study ◽  
Restitution Curve ◽  
Life Threatening ◽  
Frequency Stimulation ◽  
Human Cardiac Tissue

AbstractHigh-voltage electrical defibrillation remains the only reliable method of quickly controlling life-threatening cardiac arrhythmias. This paper is devoted to studying an alternative approach, low-voltage cardioversion (LVC), which is based on ideas from non-linear dynamics and aims to remove sources of cardiac arrhythmias by applying high-frequency stimulation to cardiac tissue. We perform a detailed in-silico study of the elimination of arrhythmias caused by rotating spiral waves in a TP06 model of human cardiac tissue. We consider three parameter sets with slopes of the APD restitution curve of 0.7, 1.1 and 1.4, and we study LVC at the baseline and under the blocking of INa and ICaL and under the application of the drugs verapamil and amiodarone. We show that pacing can remove spiral waves; however, its efficiency can be substantially reduced by dynamic instabilities. We classify these instabilities and show that the blocking of INa and the application of amiodarone increase the efficiency of the method, while the blocking of ICaL and the application of verapamil decrease the efficiency. We discuss the mechanisms and the possible clinical applications resulting from our study.

scholarly journals Dynamic three-dimensional reconstruction of the left ventricle from two-dimensional echocardiograms

1986 ◽  
Vol 8 (2) ◽  
pp. 364-370 ◽  
Author(s):  
Joel S. Raichlen ◽  
Sushma S. Trivedi ◽  
Gabor T. Herman ◽  
Martin G.St. John Sutton ◽  
Nathaniel Reicher
Keyword(s):  
Left Ventricle ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Reconstruction ◽  
Dimensional Reconstruction

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.

Electromechanical wavebreak in a model of the human left ventricle

2010 ◽  
Vol 299 (1) ◽  
pp. H134-H143 ◽  
Author(s):  
R. H. Keldermann ◽  
M. P. Nash ◽  
H. Gelderblom ◽  
V. Y. Wang ◽  
A. V. Panfilov
Keyword(s):  
Ventricular Fibrillation ◽  
Left Ventricle ◽  
Present Report ◽  
Three Dimensional ◽  
Spiral Wave ◽  
Cardiac Cells ◽  
Mechanical Activity ◽  
Wall Thickening ◽  
Orientation Field ◽  
The Stability

In the present report, we introduce an integrative three-dimensional electromechanical model of the left ventricle of the human heart. Electrical activity is represented by the ionic TP06 model for human cardiac cells, and mechanical activity is represented by the Niederer-Hunter-Smith active contractile tension model and the exponential Guccione passive elasticity model. These models were embedded into an anatomic model of the left ventricle that contains a detailed description of cardiac geometry and the fiber orientation field. We demonstrated that fiber shortening and wall thickening during normal excitation were qualitatively similar to experimental recordings. We used this model to study the effect of mechanoelectrical feedback via stretch-activated channels on the stability of reentrant wave excitation. We found that mechanoelectrical feedback can induce the deterioration of an otherwise stable spiral wave into turbulent wave patterns similar to that of ventricular fibrillation. We identified the mechanisms of this transition and studied the three-dimensional organization of this mechanically induced ventricular fibrillation.

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