Implantable defibrillator system for generating an active biphasic waveform

Claim 1

An implantable cardioverter defibrillator apparatus for discharging an active biphasic electrical countershock to an ailing human heart through at least two implantable electrodes located proximate the heart, the apparatus comprising: an internal power source for providing electrical energy; capacitance means, electrically connected between the power source and the electrodes, for generating a first phase of the biphasic countershock having a first polarity across the electrodes; inverter means, separate from the capacitance means and electrically connected between the power source and the electrodes, for generating a second phase of the biphasic countershock having a second and opposite polarity across the electrodes and actively drawing low voltage electrical energy directly from the power source during delivery of the second phase; and control means, operatively coupled to the power source, the capacitance means and the inverter means, for controlling delivery of the first phase of the biphasic countershock from the capacitance means and the second phase of the biphasic countershock from the inverter means in response to a sensing of a cardiac dysrhythmia.

Claim 12

A method for operating an implantable cardioverter defibrillator device implanted within a human patient and electrically connected to at least two implantable electrodes located proximate a human heart to treat a cardiac arrhythmia by delivering an active biphasic electrical countershock having a high voltage first phase and a low voltage second phase, the method comprising the device-implemented steps of: (a) sensing for a cardiac arrhythmia in a human patient; (b) in response to a sensing of a cardiac arrhythmia, performing the steps of: (b1) charging a capacitive charge storage system to a high voltage charge value using a low voltage power source; (b2) discharging at least a portion of the charge value stored in the capacitive charge storage system through the electrodes to produce the high voltage first phase of the biphasic countershock; (b3) generating the low voltage second phase of the biphasic countershock by using an active supply of low voltage electrical energy from the low voltage power source that is discharged through the electrodes to produce the second phase of the biphasic countershock having an opposite polarity from the first phase.

Claim 13

A method for operating an implantable cardioverter defibrillator device implanted within a human patient and electrically connected to at least two implantable electrodes located proximate a human heart to treat a cardiac arrhythmia by delivering an active biphasic electrical countershock having a high voltage first phase and a low voltage second phase, the method comprising the device-implemented steps of: (a) sensing for a cardiac arrhythmia in a human patient; (b) in response to a sensing of a cardiac arrhythmia, performing the steps of: (b1) charging a capacitive charge storage system to a high voltage charge value using a low voltage power source; (b2) discharging at least a portion of the charge value stored in the capacitive charge storage system through the electrodes to produce the high voltage first phase of the biphasic countershock; (b3) generating the low voltage second phase of the biphasic countershock by using an active supply of low voltage electrical energy from the low voltage power source that is discharged through the electrodes to produce the second phase of the biphasic countershock having an opposite polarity from the first phase.