Virtual source separation modifies cardiac tissue response to field stimulation

Robert C. Susil, Eric A. Sobie, Leslie Tung

Research output: Contribution to journalConference articlepeer-review

Abstract

In recent years, the concept of virtual electrode sources, in locations remote from the stimulating electrodes, has become increasingly important in our understanding of the mechanisms of cardiac defibrillation. One class of virtual electrodes - that of oppositely polarized virtual electrode pairs - tends to appear in bounded regions of cardiac tissue. We have examined the stimulatory effects of oppositely polarized pairs of virtual electrodes by modeling an active strip of bounded cardiac tissue. To examine the impact which these electrode source pairs have on one another, we characterized field stimulation at several tissue lengths. At large length scales (1.5 cm) we found that field stimulation strongly resembled unipolar current injection. Both the time constant and the threshold for stimulation were consistent with those for point stimulation. However, on short length scales (150 μm), field stimulation behaved very differently than point stimulation. Specifically, we found that the close proximity of oppositely polarized sources acted both to increase the stimulation threshold and to decrease the membrane charging time constant, boosting the tissue frequency response.

Original languageEnglish (US)
Pages (from-to)182-184
Number of pages3
JournalAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
Volume1
DOIs
StatePublished - Jan 1 1997
EventProceedings of the 1997 19th Annual International Conference of the IEEE Engineering in Medicine and Biology Society - Chicago, IL, USA
Duration: Oct 30 1997Nov 2 1997

ASJC Scopus subject areas

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

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