Implantable unipolar pacemaker with improved outer electrode plate
First Claim
1. In a unipolar implantable living tissue stimulator of the type including pulse generating means, a stimulating electrode electrically connected to said pulse generating means and locatable at the tissue to be stimulated by pulses supplied to said stimulating electrodes by said generating means, and outer electrode means connected to said generating means and in direct electrical contact with body saline solution which extends from said stimulating electrode to said outer electrode means to thereby provide an electrical conductive path therebetween, the improvement comprising:
- outer electrode means defining an electrically conductive surface of preselected area which is in direct electrical contact with the body saline solution when said stimulator is implanted in a body, said outer electrode means defining a plurality of electrically conductive elements whereby any substantially square area on the surface of any of said elements does not exceed a preselected maximum value which is significantly smaller than the total area of the conductive surface of said outer electrode means.
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Accused Products
Abstract
A unipolar living tissue stimulator of the implantable type with an outer plate electrode which in one embodiment consists of a flat metal plate slotted by slots to form a plurality of electrically conductive strips. Each strip is electrically in contact with any other strip through only a single path. The strips are dimensioned so that any substantially square or circular surface area on any strip is significantly smaller than the total conductive surface area of the plate. Consequently, the heating of the slotted plate due to an external alternating magnetic field is reduced significantly.
81 Citations
19 Claims
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1. In a unipolar implantable living tissue stimulator of the type including pulse generating means, a stimulating electrode electrically connected to said pulse generating means and locatable at the tissue to be stimulated by pulses supplied to said stimulating electrodes by said generating means, and outer electrode means connected to said generating means and in direct electrical contact with body saline solution which extends from said stimulating electrode to said outer electrode means to thereby provide an electrical conductive path therebetween, the improvement comprising:
outer electrode means defining an electrically conductive surface of preselected area which is in direct electrical contact with the body saline solution when said stimulator is implanted in a body, said outer electrode means defining a plurality of electrically conductive elements whereby any substantially square area on the surface of any of said elements does not exceed a preselected maximum value which is significantly smaller than the total area of the conductive surface of said outer electrode means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. In a unipolar implantable living tissue stimulator of the type including pulse generating means and a stimulating electrode electrically connected to said pulse generating means for stimulating living tissue and outer electrode means connected to said pulse generating means and being in contact with body saline solution, the improvement comprising:
said outer electrode means including a sheet of electrically conductive metal of a preselected surface area, and including a layer of electrically conductive matter surrounding and being in direct electrical contact with said sheet of metal and being in direct electrical contact with body saline solution, when said stimulator is implanted in a body, said electrically conductive matter exhibiting heat insulating properties and being characterized by a resistivity which is greater than the resistivity of said sheet of metal by a factor n, where n is on the order of not less than 10, and being further characterized by being resistive to corrosion by body saline solution, said layer of electrically conductive matter providing an electrical current path between said body saline solution and said sheet of metal and distributes heating of said sheet of metal over the entire surface thereof. - View Dependent Claims (10)
- 11. In a unipolar implantable living tissue stimulator of the type including pulse generating means powered by a source of power rechargeable by an external magnetic field adapted to induce in said stimulator, power on the order of not less than 0.5 watt, the stimulator further including an electrode connected to said pulse generating means and locatable at tissue to be stimulated and outer electrode means connected to said pulse generating means and in direct contact with body saline solution, when the stimulator is implanted in a body, improved outer electrode means to minimize the heating of said outer electrode means due to any portion of said external magnetic field passing therethrough, said improved outer electrode means defining a conductive surface of a preselected area and formed of a plurality of electrically conductive elements having dimensions so that any substantially square area on the surface of any of said elements is smaller than the total area of the conductive surface of said outer electrode means, by a factor n of not less than 5 each of said conductive elements being interconnected to any other element through a singe current path.
- 14. In a unipolar implantable living tissue stimulator of the type including pulse generating means and a stimulating electrode, electrically connected to said pulse generating means for stimulating living tissue and outer electrode means connected to said pulse generating means, and being in contact with body saline solutions, when the stimulator is implanted in a body, said outer electrode means comprising a layer of biocompatible matter which is electrically conductive and electrically coupleable to the body saline solution, said matter being characterized by heat insulating properties and by an electrical resistivity in the range of 20 microhm-cm to 400 ohm-cm.
- 17. In a unipolar implantable living tissue stimulator of the type including pulse generating means with an outer electrically conductive electrode, which is electrically connected to said pulse generating means and is in electrical contact with body saline solution when the stimulator is implanted in a body, an improved outer electrically conductive electrode comprising electrically conductive matter having a preselected surface area with which the body saline solution comes in contact, said matter being dimensioned whereby any continuous substantially square area on the surface thereof does not exceed a preselected value, said substantially square area being smaller than the total surface area of said electrically conductive matter by a factor not less than ten.
Specification