Linear electrode arrays for stimulation and recording within cardiac tissue space constants

Academic Article

Abstract

  • In this paper, we document a fabrication process that yields linear arrays of rectangular platinum black electrodes spaced 25 μm apart with edge-to-edge separation of 20 μm. The spatial arrangement is therefore sufficiently fine to insure stimulation and recording within cardiac tissue space constants, as six electrodes with dimensions of either 5 × 100 μ2, 5 × 250 μm2, or 5 × 500 μm2 were positioned in a 130- μm span in the arrays. Despite the small electrode sizes and available surface areas, favorable impedance characteristics were identifed. Averages ranged from 111 kΩ to 146 kΩ at 0.5 Hz and from 14 kΩ to 39 kΩ at 500 Hz. Differences in impedances between the electrode sizes tested were small. Potential differences (δφs) recorded using the two central electrodes during stimulation with combinations at separations of only 75 μm, 100 μm, and 125 μm had low signal noise. As a preliminary test of the use of these arrays for possible application to impedance measurements in cardiac tissue, the δφs recorded during stimulation were compared to δφs obtained from finite-difference simulations using an isotropic volume conductor model. Anticipated decays in δφ with widening electrode separation identified in those simulations matched the decays in the recorded δφs closely. These findings are significant because they suggest intracellular and interstitial microimpedance mesurements in heart experiments will be straightforward. © 2006 IEEE.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Pollard AE; Ellis CD; Smith WM
  • Start Page

  • 1408
  • End Page

  • 1414
  • Volume

  • 55
  • Issue

  • 4