High impedance, low polarization cardiac electrode

Abstract

A layered electrode having a large tissue contact area of the portion of the electrode that is electrically active and providing low polarization losses, high pacing impedance and low chronic stimulation voltage. In a fundamental embodiment, the electrode tip has an outer layer of microporous material which is permeable to conductive body fluids which covers a layer of insulating material which is provided with at least one perforation through the thickness of the material. The at least one perforation provides a localized, high current density path. Both of these layers in turn cover the exterior surface of an electrically conductive, preferably metal, electrode body. The present invention is, in a preferred embodiment, a multiple layered device having, in sequence, a) an external layer promoting tissue attachment, b) a cell exclusion layer, which prevents tissue ingrowth into the subsequent underlying layers while allowing passage of conductive fluids, c) a third layer of substantially electrical insulating material with selected or tailored perforations or through holes which provide high current density paths, d) a fourth layer that contains a electrically conductive material of high surface area and e) a fifth metallic layer of a high surface area electrode.