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.

scholarly journals Activation becomes highly organized during long-duration ventricular fibrillation in canine hearts

2010 ◽  
Vol 298 (6) ◽  
pp. H2046-H2053 ◽  
Author(s):  
Li Li ◽  
Qi Jin ◽  
Derek J. Dosdall ◽  
Jian Huang ◽  
Steven M. Pogwizd ◽  
...  
Keyword(s):  
Ventricular Fibrillation ◽  
Conduction Block ◽  
Three Dimensional ◽  
Left Ventricular ◽  
The Body ◽  
Long Duration ◽  
Surface Ecg ◽  
Electrode Matrix ◽  
Different Levels

Little is known about the three-dimensional (3-D) intramural activation sequences during long-duration ventricular fibrillation (VF), including the role of the subendocardium and its Purkinje fibers (PFs) in long-duration VF maintenance. Our aim was to explore the mechanism of long-duration VF maintenance with 3-D electrical mapping. We recorded 10 min of electrically induced VF in the left ventricular anterior free wall of six 10-kg, open-chest dogs using a 3-D transmural unipolar electrode matrix (9 × 9 × 6, 2-mm spacing) that allowed us to map intramural activation sequences. At 2.5 ± 1.8 min of VF, although the body surface ECG continued to exhibit a disorganized VF pattern, intramurally a more organized, synchronous activation pattern was first observed [locally synchronized VF (LSVF)]. This pattern occurred one or more times in all dogs and was present 33.4 ± 31.4% of the time during 5–10 min of VF. As opposed to the preceding changing complex activation sequences of VF, during LSVF, wavefronts were large and highly repeatable near the endocardium, first exciting the endocardium almost simultaneously and then rapidly spreading toward the epicardium with different levels of conduction block en route. During LSVF, PF activations always preceded working myocardium activations near the endocardium. In conclusion, long-duration VF in dogs frequently becomes highly organized in the subendocardium, with activation fronts arising in this region and passing intramurally toward the epicardium, even though the surface ECG continues to exhibit a disorganized pattern. PFs appear to play an important role during this stage of VF.

Modeling and Analysis of Heart Left Ventricle in Diastole Using Finite Element

2016 ◽  
Author(s):  
Joshua B. Seidel ◽  
J. Michael Kabo ◽  
Vidya K. Nandikolla
Keyword(s):  
Finite Element ◽  
Left Ventricle ◽  
Three Dimensional ◽  
Wall Stress ◽  
Left Ventricular ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Modeling And Analysis ◽  
End Diastolic Volume ◽  
Tissue Compliance

Finite element is used to analyze the effects of infarct on left ventricular end-diastolic function. The results for the symmetric infarct cases 1–6 demonstrated in this paper correspond to infarct percent by volume of 4, 8, 9, 16, 25 and 51% respectively. Using the developed three-dimensional model, these infarct percent by volume showed a reduction in end-diastolic volume (EDV) of 3, 5, 5, 8, 11, 17 mL respectively. Three natural infarct cases denoted A, B and C was evaluated consisting of 7%, 15% and 50% infarct region by volume respectively. The decrease in EDV for cases A, B and C were 6, 9 and 17 mL. The simulated decrease in EDV for the infarct cases was consistent with patients experiencing decreased tissue compliance. The higher left ventricle (LV) pressure resulted in an increase in wall stress opposite to the infarct for the symmetric and natural infarct cases.

DYNAMICS OF VENTRICULAR FIBRILLATION: A MODEL AND EXPERIMENTAL STUDY

1999 ◽  
Vol 07 (04) ◽  
pp. 513-527 ◽  
Author(s):  
E. VIGMOND ◽  
F. X. WITKOWSKI ◽  
L. J. LEON
Keyword(s):  
Correlation Function ◽  
Ventricular Fibrillation ◽  
Cross Correlation ◽  
Cardiac Tissue ◽  
Three Dimensional ◽  
Cross Correlation Function ◽  
Three Dimensional Model ◽  
Potential Mapping ◽  
Acute Form ◽  
Electrical Induction

Wiggers initially described that after electrical induction of ventricular fibrillation (VF) the rhythm so induced progresses in complexity [14]. Previously Witkowski et al. [15] have described two distinct phases of perfused VF. The acute form was characterized by relatively well organized activity and was observed in the first few minutes after induction. The chronic form developed after this initial reentry and was more disorganized in nature. In this paper we describe computer simulations carried out using a complex three-dimensional model of cardiac tissue. Depending on the time constant of the dynamics of the calcium current, activity ranged from organized scroll waves, to highly disorganized chaotic activity in which it was possible to identify up to 10 different vortex filaments which continually drifted and split. The model data was compared to experimental measurements via the maximum cross-correlation function described previously by Witkowski et al. [15]. We found that the max cross-correlation function for a single scroll wave ranged between 0.6 and 0.9, and is similar to what was experimentally observed from optical transmembrane potential mapping during early VF. For the highly disorganized activity the maximum cross-correlation function was in the range of 0.2, which similarly was in same range reported experimentally for fully developed VF.

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