Difibrillation system

Abstract

A defibrillation system includes circuitry and other components contained in a defibrillator housing, to which at least two defibrillation electrodes are connected, at least one defibrillation electrode being intended for intracardiac placement. This defibrillation electrode contains a flexible electrode cable with at least one elongate, electrically insulated conductor and at least one defibrillation surface disposed at the distal end of the electrode cable for delivering defibrillation pulses to the heart. The system further includes control components and circuitry for determining when defibrillation therapy, in the form of one or more pulses is to be administered. In order to provide defibrillation employing the intracardiac electrode, with a defibrillation surface that is relatively large so that the defibrillation current can be distributed so as to prevent damage to the heart, while still achieving optimum defibrillation, and so that the defibrillation electrode does not impede the flow of blood in the heart during periods when it is not used to emit pulses, the electrode head is constructed so as to be expandable, and the defibrillator housing includes control elements and circuitry operable on the electrode head via the electrode cable to cause the electrode head to expand, as needed, and to subsequently return to a non-expanded state.