Intermedics Inc.

Medtronic, Inc.

At&t Bell Laboratories

Procath Corporation

Neuromedics, Inc.

Pat L Gordon

Ross G Baker, Jr

Richard V Calfee

Barin Geoffry Haskell

Rahul Mehra

John G Keimel

John T Meador

Robert L Schmidt

Daniel Bihn

Jay Miner

Reese S Terry

Anthony J Varrichio

Robert N Bertasz

A defibrillator for providing a constant low pulsed current to a patient's heart has a high voltage capacitor for storing electrical energy. An inductor connected to the capacitor smooths out the discharge curve and produces a low current low frequency defibrillator pulse supplied to a patient's heart. The pulse is usually biphasic.

High energy defibrillator employing current control circuitry

A combined pacing and cardioversion lead system with internal electrical switching components for unipolar or bipolar sensing of electrograms, pacing at normal pacing voltages and cardioversion or defibrillation. In bipolar embodiments, an indifferent electrode, closely spaced to a sensing and pacing electrode, is coupled in common through the integral switching circuitry to a large surface area cardioversion electrode. In these embodiments, pacing and sensing is accomplished through a pair of conductors extending through the lead system to the closely spaced active and indifferent electrode pair. When cardioversion energy is applied to the indifferent electrode, the cardioversion energy is also directed to the cardioversion electrode through operation of the switching circuitry in response to the magnitude of the applied cardioversion pulse. In unipolar embodiments, a distal sensing and pacing electrode is coupled through integral switching circuitry to a large surface area cardioversion electrode. In these embodiments, only a single conductor extending through the lead to the pacing and sensing electrode is required. When cardioversion energy is applied to the pacing and sensing electrode, the cardioversion energy is also directed to the cardioversion electrode through operation of the switching circuitry in response to the magnitude of the applied cardioversion pulse.

Pacing and cardioversion lead systems with shared lead conductors

The bandwidth required for a regularly occurring signal such as a television signal, as received from a signal source can be substantially reduced by not transmitting each and every one of the horizontal scan lines. Rather, firstly, one or more selected lines may be transmitted and, secondly, instead of transmitting the remaining, unselected lines, a signal representing a predetermined arithmetic difference among predetermined ones of the scan lines may be transmitted.

Signal processor (system) for reducing bandwidth and for multiplexing a

An interrogator for remotely interrogating an internal counter of a scoliosis treatment device. An internal counter of the treatment device is incremented for those periods of time in which the treatment level of the device is in excess of a compliance level. The interrogator communicates with the internal counter by means of two serial data lines. On one data line the interrogator generates a clock signal to the internal counter for incrementing the device and on the other data line the interrogator receives a pulse indicating the internal counter has overflowed. By incrementing the internal counter through a full cycle of its maximum count the counter will retain the count present when it is interrogated. Additionally, by counting the number of, clock counts comprising the period from the overflow signal to the end of a full cycle a duplication of the count in the remote internal counter can be stored in the interrogator and subsequently displayed.

Interrogator for muscle stimulator

An external command device and an internal decoding and verification device are used to non-invasively alter the operating parameters of a programmable device implanted in an animal body. Thus, physiological changes can be easily accommodated by the implanted device. In a preferred embodiment, pulse position modulation is used to externally encode the command information. A resulting string of current pulses generates voltage spikes (in the internal decoding device) through inductively coupled coils. Each incoming data bit is verified and the entire command word is verified. After verification, the decoded command is transferred to a command register for simultaneously altering the selected operating parameters. The internal receiver circuitry may conveniently utilize energy from the induced voltage spike, using passive components for forming an output suitable for processing.

Method and apparatus for communicating with implanted body function

An improved body function assistance device is provided wherein a microprocessor controls the response of the device to various external physiological events and internal timer events. The microprocessor is adapted for use with the limited energy supply available from a battery by activating internal logic components of the processor only in response to selected events and to perform an operating routine corresponding to the 'wakeup' event. At the end of the operating routine, a new set of wakeup events is selected and the internal logic components are deactivated. A further reduction in the average operating current is obtained by providing a plurality of counting rates to minimize the number of state changes during counting cycles. The microprocessor may be provided with a fixed operating routine or may be provided with the capability of actually introducing program changes in the implanted device.

Implantable device with microprocessor control

A method and apparatus are provided for determining the compatibility between a selected implantable pacer and a patient within which the pacer is to be implanted wherein the pacer does not have to be directly connected to the patient during the compatibility check.Actual cardiac signals from the patient are digitized and a storage frame is established about a complete cardiac waveform. This cardiac waveform can be reproduced in analog form for presentation to the pacer. Further, the amplitude of the reproduced cardiac waveform may be varied in a manner determined by an active search routine wherein the threshold response of the cardiac pacer can be determined. In a preferred embodiment, the threshold response determination is also used to provide an output signal indicative of the degree of compatibility between the selected cardiac pacer and the actual patient selected to receive the pacer.

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Austin, TX, United States of America

Pat L Gordon