Methods and apparatus for a three-stage ventricular cardioversion and defibrillation therapy that treats ventricular tachycardia and fibrillation at low energy levels. An implantable therapy generator adapted to generate and selectively deliver a three-stage ventricular therapy and at least two leads operably each having at least one electrode adapted to be positioned proximate the ventricle of the patient. The device is programmed to deliver a three-stage therapy via both a far-field configuration and a near-field configuration of the electrodes upon detection of a ventricular arrhythmia. The three-stage therapy includes a first stage for unpinning of one or more singularities associated with the ventricular arrhythmia, a second stage for anti-repinning of the one or more singularities, both of which are delivered via the far-field configuration of the electrodes, and a third stage for extinguishing of the one or more singularities associated delivered via the near-field configuration of the electrodes.

A capacitor for powering an implantable medical device is described. The capacitor includes a casing having contoured surfaces to more closely conform to body contours. This means that the anode housed in the casing must also have a contoured shape substantially matching that of the casing. Accordingly, the anode is comprised of a pressed pellet having a surrounding peripheral edge extending to spaced-apart first and second major face walls. An anode lead wire comprises an embedded portion extending into the anode pellet. First and second channel-shaped recesses aligned with each other extend into the anode pellet from the first and second major face walls to intersect with the embedded lead wire portion. The first and second channel-shaped recesses also extend to opposed locations at the surrounding peripheral edge of the anode pellet. The anode pellet is bent at the aligned first and second channel-shaped recesses to provide a right anode pellet portion electrically connected to a left anode pellet portion by the embedded lead wire portion. The thusly contoured anode pellet has an anatomical shape that matches that of the contoured casing to provide an implantable capacitor that is volumetrically efficient.

Improved devices, circuits and methods of operation in implantable stimulus systems. An implantable defibrillator may comprise a charging circuit using a transformer to store and build up energy on an HV capacitor or capacitor stack, with the HV capacitor in turn coupled to an H-bridge output circuit having low and high sides for issuing therapy. A current monitoring circuitry is provided on the low side of the H-Bridge and used to form a feedback loop to control current into a transformer that converts battery voltage to a signal that charges the HV capacitor to control current through the H-bridge.

Improved devices, circuits and methods of operation in implantable stimulus systems. An implantable defibrillator may comprise an H-bridge output circuit having low and high sides, with a current controlling circuit coupled to the high side of the H-bridge output circuit and a current monitoring circuit coupled to the low side of the H-bridge output circuit. Alternate current paths to the output of the H-bridge, or to the H-Bridge itself, are used for delivering different therapies to the patient.

Improved devices, circuits and methods of operation in implantable stimulus systems. An implantable defibrillator may comprise an H-bridge output circuit having low and high sides, with a current controlling circuit coupled to the high side of the H-bridge output circuit and a current monitoring circuit coupled to the low side of the H-bridge output circuit. A bootstrap design or a DC isolating circuit or circuit element may be used in the current controlling circuit.

A medical device is configured to deliver therapeutic electrical stimulation pulses by generating frequency modulated electrical stimulation pulse signals. The medical device includes a pulse signal source and a modulator. The pulse signal source generates an electrical stimulation pulse signal having a pulse width. The modulator may include a high frequency modulator configured to modulate a frequency of the pulse signal from a starting frequency down to a minimum frequency during the pulse width. The modulator may include a low frequency bias generator to modulate the offset of the pulse signal between a minimum offset and a maximum offset in other examples.

An external defibrillator system is provided. The system includes: a graphical display; one or more sensors for obtaining data regarding chest compressions performed on a patient; and a controller configured to display on the graphical display numeric values for depth and/or rate of the chest compressions based upon the data from the one or more sensors. A method for using an external defibrillator including the steps of: obtaining data regarding chest compressions perforated on a patient; and displaying on a graphical display screen of the defibrillator numeric values for depth and/or rate of the chest compressions based upon the data is also provided.

Systems and methods related to the field of cardiac resuscitation, and in particular to devices for assisting rescuers in performing cardio-pulmonary resuscitation (CPR).

An automated external defibrillator (AED) system includes an AED operations block for controlling operational aspects of the AED system. AED operations block includes pads for attachment to a patient, an electrocardiogram monitoring circuitry for monitoring patient heartbeat, shock generating electronics for generating at least one electrical shock signal to be applied to the patient through the pads, a battery for supplying power to the AED operations block, a power management block for managing power consumption by the shock generating electronics and monitoring a power status of the battery, a memory for storing information regarding the AED system, a user-interface block for providing use instructions and receiving user input, and a controller for regulating the ECG monitoring circuitry, shock generating electronics, and the power management block. The AED system also includes a communications block, also regulated by the controller, for communicating with an external system separate from the AED system.

Defibrillator shock discharge control systems and schemes are described that control the shock discharge based at least in part on discharge capacitor voltage measurement taken after the defibrillation shock has been initiated.