David Fulton Peterson
Engineers in Saint Paul, MN

5447519, Sep 5, 1995

Mar 19, 1994

8/206486

David K. Peterson - Mounds View MN

Medtronic, Inc. - Minneapolis MN

A61N 139

607 5

An implantable cardioverter/defibrillator system provided with method and apparatus for discrimination between monomorphic arrhythmias, e. g. ventricular tachycardia from polymorphic arrhythmias, e. g. ventricular fibrillation. A fiducial point of each successive QRS complex is detected prompting the storage of sampled and digitized waveform data within a timing window bridging the point in time of fiducial point detection. Stored sets of such sampled wave shape data are compared data point to data point resulting in a sampled morphology index value for each compared set. The magnitude of the sampled morphology index value or a series such index values are analyzed to determine the presence of a single or a progression of beat-to-beat waveform changes indicative of a polymorphic single transition or progression of QRS complexes from monomorphic to polymorphic waveforms indicative of an arrhythmia that should be treated with aggressive cardioversion/defibrillation therapies. The system is preferably provided with a closely spaced and widely spaced pairs of electrodes for sensing each QRS complex of the patient's electrocardiogram. The closely spaced electrode pair is coupled to sense detect circuitry for identifying a predetermined fiducial point in the electrical signal associated with a ventricular depolarization and to counting and comparison circuitry for developing rate and onset data.

6013135, Jan 11, 2000

Apr 30, 1998

9/070862

Robert H. Kaun - Woodbury MN
David J. Peterson - Woodbury MN

Colonial Craft, Inc. - St. Paul MN

C23L 1600

118726

A method for six-sided painting of parts, such as boards, the parts having a top, bottom, sides, and ends, in a vacuum painting system having a feed conveyor, a vacuum painting chamber, and a take-out conveyor wherein the a first part is placed end-to-end with a second part on the feed conveyor, each part having a leading end and a trailing end, and the first part and second part enter the vacuum painting chamber end-to-end, the parts exiting the vacuum painting chamber onto the take-out conveyor end-to-end with the leading end of each part exiting the vacuum painting chamber first, consisting of the steps of: (a) sensing the presence of the leading end of the first part along the take-out conveyor while the trailing end of the first part is within the vacuum painting chamber; (b) moving a movable carriage along the take-out conveyor toward the vacuum painting chamber to a position intermediate the leading end and trailing end of the first part; (c) moving the movable carriage a short distance along the take-out conveyor away from the vacuum painting chamber in order to approximate the speed of the movable carriage to the speed of the take-out conveyor; (d) gripping the first part with gripping means attached to the movable carriage; (e) moving the movable carriage a short distance along the take-out conveyor away from the vacuum painting chamber in order to separate the trailing end of the first part from the leading end of the second part; and (f) releasing the first part so that the trailing end of the first part and the leading end of the second part become painted. An apparatus for carrying out the above method is also disclosed, consisting of a sensor adjacent the take-out conveyor for sensing the leading end of the first part; a relay responsive to the sensor; a movable carriage adjacent the take-out conveyor and adapted to move in either direction along the take-out conveyor and positionable along the first part on the take-out conveyor, the motion of the movable carriage being responsive to the relay; and gripping pins mounted on the movable carriage for gripping the first part, the gripping pins being responsive to the relay.

5193535, Mar 16, 1993

Aug 27, 1991

7/750679

Gust H. Bardy - Seattle WA
Walter H. Olson - North Oaks MN
David K. Peterson - Mounds View MN
Robert T. Taepke - Fridley MN

Medtronic, Inc. - Minneapolis MN

A61N 139

128419D

An implantable cardioverter/defibrillator provided with method and apparatus for discrimination between ventricular tachycardia and ventricular fibrillation. The device is provided with two pairs of electrodes, each pair of electrodes coupled to processing circuitry for identifying a predetermined fiducal point in the electrical signal associated with a ventricular depolarization. The cumulative beat to beat variability of the intervals separating the two identified fiducal points, over a series of detected depolarizations is analyzed. The result of this analysis is used to distinguish between ventricular tachycardia and ventricular fibrillation.

5344430, Sep 6, 1994

Apr 8, 1993

8/044516

Gary L. Berg - Edina MN
Martin A. Rossing - Ramsey MN
David K. Peterson - Mounds View MN
Robert A. Neumann - Blaine MN

Medtronic, Inc. - Minneapolis MN

A61N 139

607 8

An implantable defibrillator provided with a plurality of defibrillation electrodes, which may be reconfigured to define a plurality of defibrillation pathways. The device is capable of measuring the impedance along a selected defibrillation pathway, during delivery of an impedance pulse, and monitoring the success or failure of the pulse to accomplish defibrillation or cardioversion. In response to a detected failure to accomplish cardioversion in conjunction with a measured change of impedance of greater than a predetermined amount, a new defibrillation pathway is selected, which may employ some or all of the electrodes employed to define the original impedance pathway. The device also includes apparatus for varying the relative amplitude of defibrillation pulses applied to individual electrodes used in sequential or simultaneous, multiple electrode pulse regimens, in order to equalize current distribution, in response to measured pathway impedances.

5044374, Sep 3, 1991

Jul 7, 1989

7/376730

Fred Lindemans - Limbricht, NL
Clare Padgett - Minneapolis MN
Thomas Kiekhafer - Coon Rapids MN
Timothy Holleman - Ham Lake MN
John Keimel - New Brighton MN
David Peterson - Mounds View MN

Medtronic, Inc. - Minneapolis MN

A61N 105

128784

A large surface electrode optimized for use as a subcutaneous defibrillation electrode. The electrode includes an insulative electrode pad carrying a large surface electrode. Both the upper and lower surfaces of the electrode pad are covered by a fabric mesh to reduce fluid build-up at the site of implantation. The defibrillation electrode is spaced at least 0. 5" from the external periphery of the pad.