Abstract: An instrument with a covered bore for subcutaneous implantation is provided. An incising body defines a non-circular coaxial bore and includes a sharpened cutting edge that extends from a bottom distal end beyond the opening of the coaxial bore and an attachment point at a top distal end. A plunger is non-fixedly contained within the coaxial bore and slides longitudinally therein. A cover is pivotally attached at the attachment point and extends down to the bottom distal end and, when closed, the cover encloses the opening proximal to the cutting edge.

Abstract: An instrument with a two-part plunger for subcutaneous implantation is provided. An incising body defines a non-circular coaxial bore and includes a cutting edge formed on a distal end. A two-part plunger is non-fixedly contained within the coaxial bore and includes a tongue blade assembly and a plunger assembly. The tongue blade assembly is provided on a bottom surface of the coaxial bore and includes a tongue blade shaft and a thin tongue blade with a sharpened clearing edge on a distal end. The tongue blade assembly has a length exceeding the coaxial bore. The plunger assembly has a length exceeding the coaxial bore and includes a plunger shaft and a plunger affixed on a distal end. The plunger is slidably positioned on a top surface of the tongue blade.

Abstract: A microcontrolled electrocardiographic monitoring circuit with feedback control is provided. An input signal path includes an electrode, a low pass filter, and an amplifier connected in-line. The electrode senses an input signal and the amplifier outputs a filtered amplified output signal. A microcontroller circuit includes an input codec, analog-to-digital converter, and feedback generation module. The analog-to-digital converter converts the filtered amplified output signal into a data stream of discrete digital values. The feedback module identifies a pairing of drive resistor settings matched to each discrete digital value, which are output as a digital feedback signal. The output signal path includes an electrode and a buffer connected in-line. A pair of drive resistors is connected in parallel to an input terminal of the buffer and to the output terminals of the feedback module. Each drive resistor is adjusted according to the digital feedback signal, and the electrode provides an output signal.

Abstract: A device and method for defrosting a defibrillation electrode are provided. This includes an automated external defibrillator that is capable of defrosting one or more frozen electrodes. The device is includes a portable housing containing a battery powered energy source and a controller as well as at least a pair of electrodes which are operably coupled to the housing. The electrodes are designed for attachment to the chest of a patient in need of resuscitation and contain a conductive interface medium that has temperature dependent properties. A controller is configured to selectively heat the conductive interface medium by applying limited electrical impulses and raise the electrode temperature to a desired temperature range.

Abstract: A microcontrolled electrocardiographic monitoring circuit with differential voltage encoding is provided. An input signal path includes an electrode, a low pass filter, and an amplifier, which are each connected in-line. The electrode senses an input signal via a conductive surface and the amplifier outputs a filtered amplified output signal. A microcontroller circuit includes an input codec, an analog-to-digital converter, and an encoder. The analog-to-digital converter is connected to the input signal path through an output of the amplifier and converts the filtered amplified output signal into a data stream of discrete digital values. The encoder determines a differential voltage between a current discrete digital value and a prior discrete digital value in the data stream. Persistent memory is connected to the microcontroller circuit via a peripheral serial interface bus, wherein the differential voltages for each of the discrete digital values in the data stream are stored into the persistent memory.

Abstract: The present invention comprises a cardiopulmonary resuscitation (CPR) feedback device and a method for performing CPR. A chest compression detector device is provided that measures chest compression during the administration of CPR. The chest compression detector device comprises a signal transmitter operably positioned on the chest of the patient and adapted to broadcast a signal, and a signal receiver adapted to receive the signal. The chest compression detector device also comprises a processor, operably connected to the signal transmitter and the signal receiver. The processor repeatedly analyzes the signal received to determine from the signal a series of measurements of compression of the chest, and feedback is provided to the rescuer based on the series of measurements.

Abstract: An Automated External Defibrillator (AED) for delivering therapeutic electrical energy to a patient's heart comprising at least one variable capacitance capacitor having a large positive voltage coefficient such that a given amount of energy can be stored at a lower voltage than a traditional fixed capacitor having an equivalent capacitance. Due to the variable capacitance capacitor's ability to store energy at a lower voltage, initial defibrillation current levels are reduced effectively minimizing the risk of tissue damage caused by high initial current levels. In addition, the use of a variable capacitance capacitor reduces the amount of current decay throughout the discharge cycle as opposed to current AED designs utilizing fixed capacitance capacitors which experience an exponential decline in defibrillation current during the discharge cycle.

Abstract: A device and method for defrosting a defibrillation electrode are provided. This includes an automated external defibrillator that is capable of defrosting one or more frozen electrodes. The device is includes a portable housing containing a battery powered energy source and a controller as well as at least a pair of electrodes which are operably coupled to the housing. The electrodes are designed for attachment to the chest of a patient in need of resuscitation and contain a conductive interface medium that has temperature dependent properties. A controller is configured to selectively heat the conductive interface medium by applying limited electrical impulses and raise the electrode temperature to a desired temperature range.

Abstract: Methods and apparatus for assessing cardiac risks in a specific patient. One embodiment of a method in accordance with the invention comprises providing heart rate activity of a specific patient including a windowed time series relating to heart rate variability during a heart rate test. This method further includes determining a frequency domain value based on energy values of frequency bands of the heart rate variability in the windowed time series, and/or determining an aggregate power for a frequency band of the windowed time series. This method further includes assessing the risk of a cardiac event based on the frequency value and/or the aggregate power.

Abstract: A device and method for defrosting a defibrillation electrode are provided. This includes an automated external defibrillator that is capable of defrosting one or more frozen electrodes. The device is includes a portable housing containing a battery powered energy source and a controller as well as at least a pair of electrodes which are operably coupled to the housing. The electrodes are designed for attachment to the chest of a patient in need of resuscitation and contain a conductive interface medium that has temperature dependent properties. A controller is configured to selectively heat the conductive interface medium by applying limited electrical impulses and raise the electrode temperature to a desired temperature range.

Abstract: An apparatus and method for determining an optimal transchest external defibrillation waveform that provides for variable energy in the first or second phase of a biphasic waveform that, when applied through a plurality of electrodes positioned on a patient's torso, will produce a desired response in the patient's cardiac cell membranes. The method includes the steps of providing a quantitative model of a defibrillator circuit for producing external defibrillation waveforms, the quantitative model of a patient includes a chest component, a heart component, a cell membrane component and a quantitative description of the desired cardiac membrane response function. Finally, a quantitative description of a transchest external defibrillation waveform that will produce the desired cardiac membrane response function is computed. The computation is made as a function of the desired cardiac membrane response function, the patient model and the defibrillator circuit model.

Abstract: An Automated External Defibrillator (AED) for delivering therapeutic electrical energy to a patient's heart comprising at least one variable capacitance capacitor having a large positive voltage coefficient such that a given amount of energy can be stored at a lower voltage than a traditional fixed capacitor having an equivalent capacitance. Due to the variable capacitance capacitor's ability to store energy at a lower voltage, initial defibrillation current levels are reduced effectively minimizing the risk of tissue damage caused by high initial current levels. In addition, the use of a variable capacitance capacitor reduces the amount of current decay throughout the discharge cycle as opposed to current AED designs utilizing fixed capacitance capacitors which experience an exponential decline in defibrillation current during the discharge cycle.