Abstract: In an automatic external defibrillator (AED) having a ventricular fibrillation detector, the ventricular fibrillation detector may generally be defined as a filter containing both an adaptive non-linear section and a linear section. The non-linear section is preferably a complex-domain neural network that can be trained to differentiate between various rhythm patterns and produce linear data for input to the linear section. The linear section is preferably an ongoing, continuous operation based on a sliding window of a predetermined time period, e.g., a tapped time-delay filter. In combination the non-linear section and linear section of the filter operate to detect and extract artifacts from a patient's ECG signal in a substantially accurate fashion so that the determination to deliver a defibrillation pulse may be accurately made.

Abstract: An automatic capacitor maintenance system for an implantable cardioverter defibrillator (ICD) reforms the capacitor system of the ICD based on measurements relating a current leakage and a charge time of the capacitor system as determined at a stable low voltage state. Preferably, differential changes in current leakage across the capacitor system are monitored and the capacitor system is reformed based on a pre-set estimated charge time. The automatic capacitor maintenance system produces significant savings in the amount of battery energy consumed to reform the capacitor system of an ICD, while maintaining the capacitor system at an optimum charging efficiency so as to insure high reliability of both the capacitor system and the ICD.

Abstract: A staged energy storage system provides electrical energy to an implantable biomedical device by using the combination of a first stage energy source and a second stage energy concentration system. The second stage energy concentration system allows a lower density and/or lower voltage energy source to be used as the first stage energy source, thereby decreasing the battery cost, size and weight. In one embodiment, the second stage energy concentration system comprises a rechargeable battery. In another embodiment, the second stage energy capacitor system comprises a high energy density capacitor system. The staged energy storage system is ideal for internally charging a pulse-generating capacitor system within an implantable cardioverter defibrillator. In this embodiment, a high voltage transformer has a secondary side that is electrically connected to the pulse-generating capacitor system.

Abstract: A main energy delivery electrical circuit for use in an implantable cardioverter defibrillator device comprises a low power output primary defibrillator battery, a high power output intermediate power intensifying capacitor system, a switch for permitting the intermediate power intensifying capacitor system to rapidly charge a main energy delivery capacitor, and a main energy delivery capacitor. The main energy delivery capacitor is configured for discharging, in a first pulse, an electrical charge derived from the primary battery, and for discharging certain subsequent pulses of electrical charge derived from the intermediate power intensifying capacitor system. The circuit permits the implantable cardioverter defibrillator device to deliver multiple closely spaced defibrillation pulses to a heart.