Methods and systems are provided that comprise: sensing cardiac events of a heart; utilizing one or more processors to perform: declaring a ventricular fibrillation (VF) episode based on the cardiac events charging a single charge storage capacitor; delivering a multi-phase VF therapy that includes phase I and phase II therapies, wherein: a) during the phase I therapy, a combination of two or more medium voltage (MV) shocks are delivered entirely from the single charge storage capacitor; and b) during the phase II therapy, a low voltage pulse train is delivered at least partially from the single charge storage capacitor. Methods and systems are provided that comprise delivering first and second pulses of at least a first biphasic shock, wherein a parallel-series reconfiguration circuit connects and configures the capacitors of the capacitor bank in a parallel configuration to deliver a parallel biphasic shock; connecting the capacitors of the capacitor bank in a series configuration; and delivering first and second pulses of a second biphasic shock while the capacitors are connected in series to deliver a series biphasic shock.

Automated External Defibrillator (AED) devices may include a high voltage capacitor (HV Cap) configured to store energy required to deliver a defibrillation shock to a patient; batteries configured to charge the HV Cap; a DC/DC converter circuit including a high voltage transformer, a FET switch with associated driver, and a rectifying diode; an H-bridge circuit configured to transform energy released from the HV Cap into a bi-phasic pulse; and a memory and microprocessor configured to operate the AED device. In particular, the HV Cap, the DC/DC converter circuit, the H-bridge circuit, the one or more batteries, and the memory and the microprocessor may contained in a pocket-sized housing, the AED device may be configured to continuously monitor and adjust the rate at which the batteries charge the HV Cap, and the AED device may include a variable frequency relaxation oscillator circuit configured to acquire a patients Z-body measurement.

A method and a device for defibrillation. When a shock is generated, energy is transmitted from the low-voltage range to a high-voltage range, at least one current surge being generated in the low-voltage range, stepped up to the high-voltage range and guided to electrodes. An energy supply, power electronics and an energy storage device are used in the low-voltage range.

Techniques are disclosed for modulating the generation of charge current by operational circuitry included in an implantable medical device (IMD) for delivery of an induction stimulation pulse waveform by the IMD. The modulation may include modulating a charging circuit of the operational circuitry to facilitate the regulation of the induction stimulation pulse waveform. The techniques include monitoring an electrical parameter of a charging path during the delivery of the induction stimulation pulse and modulating the charging circuit based on the monitored electrical parameter.

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.

An implantable pulse generator comprises a pulse generation device generating an output pulse, the pulse generation device comprising a control unit, shock generation circuitry and output circuitry. The shock generation circuitry comprises a first energy storage device, a second energy storage device and a switching device. The switching device is electrically connected to the first energy storage device, and is configured to connect, in a closed state, the first energy storage device with the second energy storage device, and to disconnect, in an open state, the first energy storage device from the second energy storage device. The shock generation circuitry configured to generate an output pulse by supplying energy to the output circuitry, in the open state, from the first energy storage device via a first connection line and, in the closed state, from the first energy storage device and the second energy storage device via a second connection line.

Automated External Defibrillator (AED) devices may include a high voltage capacitor (HV Cap) configured to store energy required to deliver a defibrillation shock to a patient; batteries configured to charge the HV Cap; a DC/DC converter circuit including a high voltage transformer, a FET switch with associated driver, and a rectifying diode; an H-bridge circuit configured to transform energy released from the HV Cap into a bi-phasic pulse; and a memory and microprocessor configured to operate the AED device. In particular, the HV Cap, the DC/DC converter circuit, the H-bridge circuit, the one or more batteries, and the memory and the microprocessor may contained in a pocket-sized housing, the AED device may be configured to continuously monitor and adjust the rate at which the batteries charge the HV Cap, and the AED device may include a variable frequency relaxation oscillator circuit configured to acquire a patients Z-body measurement.

An implantable system includes an implantable medical device (IMD) and a non-transvenous lead that is configured to be implanted outside of a heart. The IMD includes an output configured to be connected at least to the lead, a current generator (CG) circuit configured to generate pacing pulses, a switching circuit coupled between the CG circuit and the output, one or more capacitors coupled in parallel with the CG circuit and the switching circuit, and a control circuit coupled to the CG circuit. The control circuit is configured to manage the CG circuit to generate the pacing pulses with a constant current at the output.

In one embodiment, a wearable cardioverter defibrillator (WCD) is described. The WCD includes a support structure worn by a patient. A processor is coupled to the support structure. The WCD also includes a discharge circuit coupled to an energy storage module, the discharge circuit configured to discharge the stored electrical charge through a body of the patient. The wearable cardioverter defibrillator also includes a user interface housing at least one sensor and responsive to changes in device orientation. The processor is configured to detect a motion at the user interface and determine when the motion is patient-activated. When the motion is patient-activated, the processor determines a direction of rotation. The processor determines an orientation of a display at the user interface based on the direction of rotation and orients the display at the user interface to appear upright to the patient.

Apparatus and methods for generating pulse pacing in a wearable cardioverter defibrillator (WCD). In one aspect the WCD circuitry includes a power source such as a battery coupled to a charger that provides charge energy to an energy storage module. Control circuitry is operatively coupled to the charger and the output circuitry, and configured to cause the WCD circuitry to generate pacing pulses delivered to therapy electrodes (attached to an ambulatory patient) without a current source. The WCD circuitry includes one or more processing elements that are used to execute instructions provided by one or more software modules that are configured to support various functionality, including controlling generation of pacing pulses.