Temporal variability of defibrillation threshold in a two-dimensional supercomputer model of 'ventricular fibrillation'

Matthew G. Fishier, Nitish V. Thakor

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have investigated the question: Do defibrillation thresholds (DFTs) vary during an episode of 'fibrillation,' and if so, what are the cellular mechanisms involved? Unstable microreentry ('fibrillation') and defibrillation (DF) shocks were simulated in a two-dimensional model of cardiac tissue on a massively parallel processor Connection Machine. The modelled tissue consisted of 16384 (128×128) 100 × 100 μm2 ventricular patches that obeyed modified Beeler-Reuter membrane kinetics. Reentry was initiated by stimulating the central region of the sheet during the repolarization phase of a passing planar wavefront. The DFT was then determined for several times following this premature stimulus. DFTs remained low (< 13 μA/cm2) until the initial figure-of-eight reentry degenerated into multiple unstable vortices (DFT ≈ 21 μA/cm2). Superimposed on this jump in DFTs was a small (±2.5 μA/cm2) quasi-periodic oscillation in DFTs whose average frequency correlated with the rotational frequency of the vortices. Therefore, we conclude that (1) there exists temporal variation in DFTs during fibrillation, (2) DFTs are lower during early fibrillation, and (3) DF shocks above ≈ 24 μA/cm2 are always successful.

Original languageEnglish (US)
Title of host publicationProceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS 1992
EditorsRobert Plonsey, Swamy Laxminarayan, Jean Pierre Morucci, Jean Louis Coatrieux
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages626-627
Number of pages2
ISBN (Electronic)0780307852
DOIs
StatePublished - Jan 1 1992
Event14th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS 1992 - Paris, France
Duration: Oct 29 1992Nov 1 1992

Publication series

NameProceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
Volume2
ISSN (Print)1557-170X

Conference

Conference14th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS 1992
CountryFrance
CityParis
Period10/29/9211/1/92

ASJC Scopus subject areas

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

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