Cardiac Pacemakers, Inc.

Control Data Corporation

American Medical Systems, Inc.

Robert D Dreher

William J Linder

James O Gilkerson

David B Krig

William L Zimmer

Jan D Wald

Charles C Kuyava

David W Kelly

Conrad L Sowder

William E Bradley

Perry A Mills

William M Klatt

Brian P Brockway

Daniel E Huntwork

Douglas C Morrison

Brock S Lindstedt

Carol G Stadler

Brian Kuhnley

Elden Roger Larson

A system and method for selectively treating a ventricular tachycardia based on sensed atrial and ventricular intervals from the patient's heart. A detection window of the ten most recent atrial and ventricular intervals are analyzed for the occurrence of either tachycardia or fibrillation. When a majority of the sensed intervals are satisfied, the apparatus starts a duration time interval. Ventricular intervals and atrial intervals are compare, ventricular interval greater than the atrial interval by a bias factor the system delivers tachycardia therapy to the heart. Alternatively, the method withholds tachycardia therapy to the heart when the atrial rate is classified as atrial fibrillation and the ventricular response is unstable.

Apparatus and method for treating ventricular tachyarrhythmias

A method and apparatus for generating a multiphasic defibrillation/cardioversion waveform as well as a multiphasic fibrillation inducing pulse train. The multiphasic fibrillation inducing waveform being applied to the same electrodes as the defibrillation/cardioversion waveform.

Fibrillation induction method and system for implantable devices

A method and apparatus for automatically adjusting the sensing threshold in an automatic implantable cardioverter/defibrillator with pacing capability. Fixed sensitivity is used for a specified interval following each pacing pulse and automatic sensitivity adjustment is used when spontaneous cardiac depolarization is detected. For spontaneous cardiac depolarization, the sensing threshold is automatically adjusted to a value proportional to the amplitude of the sensed cardiac signal. The sensing threshold continuously decreases between sensed cardiac depolarizations, ensuring that a lower level cardiac signal will be detected. When a pacing pulse is delivered, the sensing threshold is set to a fixed value and held at that value for a predetermined period of time such that the sensing threshold will not be affected by the cardiac response evoked by the pacing pulse. At the end of the predetermined period of time, the sensing threshold is decreased as it would following a spontaneous cardiac depolarization.

Automatic sensitivity control in an implantable cardiac rhythm

A programmable cardiac pacemaker that is selectively programmable via a radio frequency communications link into one of a plurality of a single and dual chamber pacing modes. Depending upon the mode selected, an associated plurality of pacing parameters may be programmed, each within a predetermined range of possible magnitudes. The pacemaker includes a rate smoothing function for preventing the rate interval from changing by more than a predetermined percentage on a cycle-to-cycle basis; and a graceful degradation function for causing the ventricular pacing rate to decay when the atrial rate exceeds a programmed upper rate limit for a predetermined length of time. A graceful degration onset time and rate of decay are also programmable. Additionally, the pacemaker contains a set of pre-programmed alternative pacing parameters for at least one mode and which can be independently reverted to. The pacemaker control circuitry is organized about a central bus into an I/O controller and a pacing controller. Pacing control is continuous and its I/O communications operate on a prioritized basis. I/O control permits the programming of any register and the interrogation of a variety of analog parameters associated therewith.

Programmable multi-mode cardiac pacemaker

The urethral catheter puller described in this application provides a convenient apparatus for performing urological diagnostic procedures such as urethral pressure profilometry and urethral electromyographic profilometry. In practice, a urethral catheter is mounted on catheter supports attached to the boom of the puller. The boom is equipped with positioning apparatus so that the catheter supports may be positioned in close proximity to the patient. The puller allows the catheter to be pulled in a horizontal or vertical direction, thus allowing the patient to stand or lie in a bed during the diagnostic procedure. The catheter supports are equipped with suitable structures to control the motion of the catheter as it is withdrawn from the urethra of the patient. A variable speed drive is provided to control the rate at which the catheter is withdrawn.

Urethral catheter puller

A frequency modulation oscillator is provided having three or more output frequencies corresponding to three or more possible input signals, the output frequency being a phase continuous frequency modulated signal with no discontinuities. For each desired output frequency, there is an input amplifier, responsive to an input binary signal, the output of that amplifier being summed with the outputs of the other amplifiers. For each input amplifier there is an active feedback network containing a delay element which will produce oscillation in the associated amplifier, the active feedback network from each amplifier being isolated from the other amplifiers and feedback networks.

Plural oscillator phase continuous frequency encoder

A frequency modulation oscillator circuit is provided having three or more output frequencies corresponding to three or more possible input signals, the output frequency being a phase continuous frequency modulated signal with no discontinuities. For each desired output frequency, there is an input amplifier, responsive to an input binary signal, the output of that amplifier being summed with the outputs of the other amplifiers. For each input amplifier there is an active feedback network containing a delay element which will produce oscillation in the associated amplifier, the active feedback network from each amplifier being isolated from the other amplifiers and feedback networks. Input amplifiers comprising differential amplifiers emitter coupled to transistor switches are shown together with common base feedback amplifiers emitter coupled to the collectors of one of the transistors comprising the input differential amplifier.

Plural transistor oscillator phase continuous frequency encoder circuit

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Roseville, MN, United States of America

Robert D Dreher