Electrical 'hot spot' as a mechanism of defibrillation

Ravi Ranjan, Matthew G. Fishler, Nitish V. Thakor

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

3 Scopus citations


The excitation threshold of isolated cardiac cells has been shown to be sensitive to the direction of applied electric field. To further explore this relationship, we developed a realistic two-dimensional finite element model of a cardiac cell. The model was used to determine the spatial distributions of transmembrane voltages produced by a uniform electric field applied across the cell. With a 5 V/cm field applied parallel to the cell axis, the maximum absolute transmembrane voltages measured at either end of the cell were 39.1 mV and 46.5 mV (signs depend on polarity of applied field), while 40.5 mV and 44.8 mV with the field perpendicular to the cell axis. More significantly however, we found that these highest potentials were concentrated at distinct sites on the membrane. Thus, we hypothesize that the depolarization of a cell due to the defibrillation shock initiates at one of these 'hot spots' whose exact location depends on the direction and polarity of the field, and shape of the cell. Our computational results are in good agreement with experimental results suggesting that a nonuniform cell shape does have an important bearing on the subsequent excitation thresholds of that cell.

Original languageEnglish (US)
Title of host publicationComputers in Cardiology
PublisherPubl by IEEE
Number of pages2
ISBN (Print)0818654708
StatePublished - Dec 1 1993
EventProceedings of the 1993 Conference on Computers in Cardiology - London, UK
Duration: Sep 5 1993Sep 8 1993

Publication series

NameComputers in Cardiology
ISSN (Print)0276-6574


OtherProceedings of the 1993 Conference on Computers in Cardiology
CityLondon, UK

ASJC Scopus subject areas

  • Computer Science Applications
  • Cardiology and Cardiovascular Medicine


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