Patterns of wave break during ventricular fibrillation in isolated swine right ventricle

2001 ◽  
Vol 281 (1) ◽  
pp. H253-H265 ◽  
Author(s):  
Moon-Hyoung Lee ◽  
Zhilin Qu ◽  
Gregory A. Fishbein ◽  
Scott T. Lamp ◽  
Eugene H. Chang ◽  
...  
Keyword(s):  
Ventricular Fibrillation ◽  
Transmembrane Potential ◽  
Three Dimensional ◽  
Single Mechanism ◽  
Tissue Surface ◽  
Potential Recording ◽  
Surface Patterns ◽  
Optical Maps ◽  
Target Wave ◽  
Wave Break

Several different patterns of wave break have been described by mapping of the tissue surface during fibrillation. However, it is not clear whether these surface patterns are caused by multiple distinct mechanisms or by a single mechanism. To determine the mechanism by which wave breaks are generated during ventricular fibrillation, we conducted optical mapping studies and single cell transmembrane potential recording in six isolated swine right ventricles (RV). Among 763 episodes of wave break (0.75 times · s−1· cm−2), optical maps showed three patterns: 80% due to a wave front encountering the refractory wave back of another wave, 11.5% due to wave fronts passing perpendicular to each other, and 8.5% due to a new (target) wave arising just beyond the refractory tail of a previous wave. Computer simulations of scroll waves in three-dimensional tissue showed that these surface patterns could be attributed to two fundamental mechanisms: head-tail interactions and filament break. We conclude that during sustained ventricular fibrillation in swine RV, surface patterns of wave break are produced by two fundamental mechanisms: head-tail interaction between waves and filament break.

scholarly journals Filament Dynamics during Simulated Ventricular Fibrillation in a High-Resolution Rabbit Heart

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Pras Pathmanathan ◽  
Richard A. Gray
Keyword(s):  
High Resolution ◽  
Ventricular Fibrillation ◽  
Electrical Activity ◽  
Three Dimensional ◽  
Coronary Vessels ◽  
Rabbit Heart ◽  
Filament Dynamics ◽  
Surface Patterns ◽  
Time Specific ◽  
Whole Heart

The mechanisms underlying ventricular fibrillation (VF) are not well understood. The electrical activity on the heart surface during VF has been recorded extensively in the experimental setting and in some cases clinically; however, correspondingtransmuralactivation patterns are prohibitively difficult to measure. In this paper, we use a high-resolution biventricular heart model to study three-dimensional electrical activity during fibrillation, focusing on the driving sources of VF: “filaments,” the organising centres of unstable reentrant scroll waves. We show, for the first time, specific 3D filamentdynamicsduring simulated VF in a whole heart geometry that includes fine-scale anatomical structures. Our results suggest that transmural activity is much more complex than what would be expected from surface observations alone. We present examples of complex intramural activity, including filament breakup and reattachment, anchoring to the thin right ventricular apex; rapid transitions among various filament shapes; and filament lengths much greater than wall thickness. We also present evidence for anatomy playing a major role in VF development and coronary vessels and trabeculae influencing filament dynamics. Overall, our results indicate that intramural activity during simulated VF is extraordinarily complex and suggest that further investigation of 3D filaments is necessary to fully comprehend recorded surface patterns.

scholarly journals Experimental and Numerical Investigation of 3D Dam-Break Wave Propagation in an Enclosed Domain with Dry and Wet Bottom

2021 ◽  
Vol 11 (12) ◽  
pp. 5638
Author(s):  
Selahattin Kocaman ◽  
Stefania Evangelista ◽  
Hasan Guzel ◽  
Kaan Dal ◽  
Ada Yilmaz ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Dam Break ◽  
Dam Failure ◽  
Navier Stokes ◽  
Negative Wave ◽  
Through Flow ◽  
Instantaneous Removal ◽  
Surface Patterns

Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.

scholarly journals Endocardial activation during ventricular fibrillation in normal and failing canine hearts

2000 ◽  
Vol 279 (4) ◽  
pp. H1737-H1747 ◽  
Author(s):  
Gordon L. Pierpont ◽  
Sumeet S. Chugh ◽  
John A. Hauck ◽  
Charles C. Gornick
Keyword(s):  
Ventricular Fibrillation ◽  
Balloon Catheter ◽  
Three Dimensional ◽  
Left Ventricular ◽  
Multielectrode Array ◽  
Three Dimensional Model ◽  
Centroid Frequency ◽  
Rapid Ventricular Pacing ◽  
Fft Analysis ◽  
Endocardial Activation

Because congestive heart failure (CHF) promotes ventricular fibrillation (VF), we compared VF in seven dogs with CHF induced by combined myocardial infarction and rapid ventricular pacing to VF in six normal dogs. A noncontact, multielectrode array balloon catheter provided full-surface real-time left ventricular (LV) endocardial electrograms and a dynamic color-coded display of endocardial activation projected onto a three-dimensional model of the LV. Fast Fourier transform (FFT) analysis of virtual electrograms showed no difference in peak or centroid frequency in CHF dogs compared with normals. The average number of simultaneous noncontiguous wavefronts present during VF was higher in normals (2.4 ± 1.0 at 10 s of VF) than in CHF dogs (1.3 ± 1.0, P < 0.005) and decreased in both over time. The wavefront “turnover” rate, estimated using FFT of the noncontiguous wavefront data, did not differ between normals and CHF and did not change over 5 min of VF. Thus the fundamental frequency characteristics of VF are unaltered by CHF, but dilated abnormal ventricles sustain fewer active wavefronts than do normal ventricles.

Comparison Between Isotropic and Anisotropic Electrical Properties of a DTI-Based Cardiac Model

2008 ◽  
Author(s):  
Ana Maria Saaibi ◽  
Isaac Chang ◽  
Min-Sig Hwang ◽  
Malisa Sarntinoranont
Keyword(s):  
Electrical Properties ◽  
Ventricular Fibrillation ◽  
Cardiac Function ◽  
Cardiac Arrhythmias ◽  
Three Dimensional ◽  
Delicate Balance ◽  
Cardiac Model ◽  
Myocardial Fibers ◽  
Fiber Organization ◽  
Cardiac Fibers

Cardiac function is influenced by the three-dimensional organization of the myocardial fibers. Cardiac fibers are arranged in a circumferential, longitudinal, and a sheet-like fashion, forming counter-wound helices from the base to the apex of the heart. This fiber organization is responsible for the delicate balance between mechanical and electrical functioning of the heart. When electrical disruption of this coordinated function occurs, this is associated with cardiac arrhythmias which may lead to more serious conditions like ventricular fibrillation.

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