Hewlett-packard Company

Inovise Medical, Inc.

Richard C Myers

Robert A Warner

Alan V Andresen

David J Lerman

Ron H S Selvester

A method for differentiating acute myocardial infarction (AMI) from other ECG abnormalities. The method is performed by modeling selected ECG confounders that tend to obscure AMI evidence in the ECG waveform, and by purging a subject's ECG waveform of the effect(s) of these confounders through linking selected confounder models with an appropriate, computer-implementable purge algorithm.

Differentiating acute myocardial infarction from other ECG abnormalities

A circuit for driving a power transistor in pulse mode, particularly adapted for use in a defibrillator. The gate of the power transistor is connected to the drain of a depletion mode transistor so no charge can build up at the gate of the power transistor when the depletion mode transistor is in its normal, conducting state. An electrical path is provided which allows current to flow, in response to a control signal, so that negative charge builds up at the gate of the depletion mode transistor, causing it to switch off (non-conducting), at which point the same current flow begins to charge the gate of the power transistor, switching it on. When the current flow is reversed, the gate of the depletion mode transistor is discharged and it switches back on, causing the gate of the power transistor to also discharge and turn the power transistor off. The various components are selected such that leakage current is less than 1 .mu.a with the resulting power pulse lasting about 25 ms. The power transistor is preferably a MOSFET or IGBT, and the depletion mode transistor is preferably a MOSFET or a JFET.

Isolated pulse mode driver for power transistor

A defibrillator incorporates a method and device for determining the energy delivered to and electrical resistance of biological tissues. The defibrillator's method and device achieve these determinations by measuring the pre-discharge voltage on the defibrillator's capacitors which are to be discharged into the body; measuring the post-discharge voltage across the capacitors which are subsequently discharged into the biological tissues; and calculating both the energy delivered to the biological tissues and the electrical resistance of the biological tissues on the basis of the measured pre-discharge and post-discharge defibrillator capacitor voltages.

Defibrillator method and system for making post-discharge measurements

A transcutaneous cardiac pacing system has one or more cutaneous electrodes suitable for attachment to a human patient and a transcutaneous pacing system coupled to supply pacing pulses to the patient via the cutaneous electrodes. The pacing pulses are effective to stimulate cardiac activity in the patient. The transcutaneous cardiac pacing system also includes a transcutaneous electrical nerve stimulation system coupled to supply nerve stimulation pulses to the patient via the same electrodes. The nerve stimulation pulses are effective to mitigate any discomfort that the patient might experience from the transcutaneous pacing pulses. The system thereby provides effective and tolerable emergency cardiac pacing without introduction of intravenous drugs or sedation of the patient.

System and method for administering transcutaneous cardiac pacing with

A driver for a power transistor (a MOSFET or IGBT) uses a transformer to isolate the power supply from the control signal, but uses very low power components on the isolated side to allow use of a physically small transformer. The control signal is one of two frequencies, and the isolated side of the driver includes a circuit for detecting which of the two frequencies is present. One frequency is preferably twice as much as the other. The output of the frequency detection circuit switches between low and high states depending on the frequency present, and the output of this circuit is connected to the input of a transistor driver circuit which charges the gate of the power transistor.

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McMinnville, OR, United States of America

Richard C Myers