Abstract/Details

Spectral analysis of optical maps in isolated rabbit hearts during ventricular fibrillation and spontaneous termination


2005 2005

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Abstract (summary)

Ventricular fibrillation (VF) is the leading cause of death in the western world. Within a few minutes of onset of VF, irreversible damage to the brain and heart occurs leading to death. The only effective treatment for VF at present is defibrillation and unfortunately it is not always successful. Only 1 in 20 out of hospital VF patients are defibrillated successfully but patients do not survive. Hence, it is crucial to understand the basic mechanism of VF to improve defibrillation efficacy and explore alternative treatment options. An optical mapping technique employs imaging of voltage dependent fluorescent dye to visualize electrical activity in isolated animal hearts allowing the study of electrophysiologic properties during fibrillation.

The N-point fast Fourier transform (FFT) has been widely used to analyze optical map data to study activation rates and patterns during fibrillation. Dominant frequency (DF) was extracted from each pixel of the optical map by peak detection of the frequency spectrum obtained using the N-point FFT method. The values in the DF maps were representative of the rate of activation for the corresponding regions and displayed several domains of uniform DF values with distinct boundaries between the domains. Results indicate that spectral peak detection precision is improved when continuous Fourier transform (CFT) was used rather than the N-point FFT method. Possible errors while using N-point FFT are shown in comparison with CFT. DF maps obtained using CFT revealed nuances that went unnoticed in DF maps obtained using N-point FFT. Specifically, gradients between some DF domains were observed and the conduction pattern along such gradients has not been studied previously. Time-space plots and apparent conduction velocity changes studied along these gradients revealed patterns similar to classic Wenckebach type conduction block. However, the gradient patterns are speculated to be due to a Doppler effect of rotor drift during fibrillation. This drift causes apparent conduction velocity changes and may lead to wavebreak due to wavefront-wavetail interaction and play an important role in maintenance of fibrillation.

Typically VF leads to death unless defibrillated. In rare cases, VF reverts back to normal sinus rhythm spontaneously in humans. However, spontaneous reversion to normal sinus rhythm is commonly observed in small, young animals. (Abstract shortened by UMI.)

Indexing (details)


Subject
Biomedical research;
Anatomy & physiology;
Animals
Classification
0541: Biomedical research
0433: Anatomy & physiology
0433: Animals
Identifier / keyword
Applied sciences; Biological sciences; Fast Fourier transform; Optical maps; Spontaneous termination; Ventricular fibrillation
Title
Spectral analysis of optical maps in isolated rabbit hearts during ventricular fibrillation and spontaneous termination
Author
Joel, Suresh Emmanuel
Number of pages
105
Publication year
2005
Degree date
2005
School code
2383
Source
DAI-B 66/03, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542020247, 0542020246
Advisor
Wetzel, Paul A.
University/institution
Virginia Commonwealth University
University location
United States -- Virginia
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3166869
ProQuest document ID
305352655
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305352655
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