Patent ID: 6633780
Filing Date: 2003-10-14
Classification: A61N

Abstract:
An implantable cardioverter defibrillator (ICD) system for applying electric shock to a heart of a patient in a shock applying mode, the ICD system comprising:an internal electrode adapted to be placed inside of the heart of the patient; a quasi-Faraday cage including a plurality of different electrodes, so that the electric shock is to be applied between the quasi-Faraday cage which is adapted to be located outside of the heart and the internal electrode adapted to be placed inside of the heart; wherein said electrodes of the quasi-Faraday cage are adapted to be wrapped around at least about 50% of the heart during application of the electric shock so as to confine a significant portion of a defibrillation shock field to the heart itself so as to prevent the shock from significantly stimulating extracardiac muscle(s) and/or nerve(s) tissue; switching circuit; and wherein said electrodes of said quasi-Faraday cage are selectively coupleable to one another via said switching circuitry so that in a mode of operation of the ICD system where no shock is applied to the heart the electrodes of said quasi-Faraday cage are electrically isolated from one another, and in the shock-applying mode of the ICD system where shock is applied to the heart the electrodes of said quasi-Faraday cage are electrically coupled to one another via said switching circuitry so that the electric shock is adapted to be applied to the heart between (a) the internal electrode, and (b) the coupled electrodes of said quasi-Faraday cage so that application of the shock to a patient is less painful.