Importance

Loading Importance Indicators...

Abstract

An implantable cardioverter defibrillator (ICD) apparatus produces a capacitive-discharge cardioversion/defibrillation countershock to be delivered through defibrillation electrodes adapted to be implanted in a human patient. The ICD apparatus is a self-contained human implantable device including a pulse-generating capacitor system, a battery system, a sensing system, and a control system. In response to a detected cardiac dysrhythmia, the ICD apparatus selectively charges and discharges the capacitor system through the defibrillation electrodes to generate the capacitive-discharge cardioversion/defibrillation countershock. Circuitry is added to the ICD apparatus to deliver a back-charging pretreatment pulse to the defibrillation electrodes immediately prior to delivery of the cardioversion/defibrillation countershock. The back-charging pretreatment pulse is a low-energy pulse having a polarity opposite from an initial polarity of the cardioversion/defibrillation countershock. By delivering the back-charging pretreatment pulse, an inter-electrode impedance of the defibrillation electrodes is reduced and a current of the cardioversion/defibrillation countershock is increased. The voltage multiplier and second switch system deliver a low voltage back charging charge of a polarity opposite to that of the defibrillation pulse to the electrodes.

Loading the Abstract Image...

First Claim