DAVID EUGENE SWANSON
Pilots at Teal Cv, Saint Paul, MN

5107834, Apr 28, 1992

Jan 30, 1991

7/647658

Raymond E. Ideker - Durham NC
Paul A. Guse - Durham NC
Douglas J. Lang - Arden Hills MN
David K. Swanson - Roseville MN
Roger W. Dahl - Andover MN

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 139

128419D

A cardioversion/defibrillation system employing a dual biphasic and multi-electrode discharge technique for effectively defibrillating the heart by creating a voltage gradient throughout substantially all of the heart which is above a critical voltage gradient while delivering a minimum energy shock. Effective cardioversion/defibrillation is accomplished by delivering two shocks to the heart. The first shock is at an energy level lower than that typically necessary to cardiovert/defibrillate the heart alone, and is applied between a first pair of cardioversion/defibrillation electrodes. The second shock is at an energy less than the first shock and is applied between a second pair of electrodes to shock the area of the myocardium provided with an inadequate voltage gradient from the first shock. The voltage gradient in the low gradient areas is boosted above the minimum gradient necessary to defibrillate. Thus, substantially the entire myocardium is depolarized by a voltage gradient above the critical voltage gradient, but with the total shock strength of the first and second shocks being substantially reduced.

5203348, Apr 20, 1993

Jun 6, 1990

7/533886

Roger W. Dahl - Andover MN
David K. Swanson - Roseville MN
Stephen J. Hahn - Roseville MN
Douglas J. Lang - Arden Hills MN
John E. Heil - St. Paul MN

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 105

128784

Implantable electrodes for defibrillation are formed of pluralities of electrode segments. Each of the segments is relatively long and narrow. The electrode segments can be parallel and spaced apart from one another a distance at least ten times the nominal width, with one end of each segment mounted to a transverse distal portion of an electrically conductive lead coupling the electrode to a defibrillation pulse generator. Alternatively, segments can branch or radiate outwardly from a common junction. In yet another arrangement, electrode segments are portions of a single conductive path at the distal end of a lead from a pulse generator, arranged in either a spiral configuration or a serpentine configuration which can align electrode segments side by side, parallel and spaced apart. The electrode segments can be formed of composite conductors in the form of titanium ribbons or wires with a sputtered outer layer of platinum, or a silver core in a stainless steel tube, with a platinum layer formed onto the tube. The electrodes are highly compliant yet can provide large effective areas for defibrillation, enabling a transthoracic pulsing arrangement of two electrodes on opposite sides of the heart, implanted subcutaneously outside of the thoracic region.

5018523, May 28, 1991

Apr 23, 1990

7/512363

Stanley M. Bach - Shoreview MN
Douglas J. Lang - Arden Hills MN
David K. Swanson - Roseville MN
Roger W. Dahl - Andover MN

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 1362

128419PG

An apparatus for stimulating and sensing evoked response to stimulus in the heart. First and second electrodes are in electrical contact with the heart, a third indifferent electrode is also in electrical contact with the heart. A pacemaker provides stimulus signals through the electrodes in the stimulating mode of operation. The first and second electrodes are switched through switching apparatus wherein in the first mode the first and second electrodes are maintained at equal electrical potentials, and in a second, sensing mode, the switch operates between the first and second electrodes so as to allow the first and second electrodes to act as bipolar sensing leads. Evoked response is sensed by a differential amplifier having a first differential input connected to the first electrode and a second differential input connected to the second electrode. The differential amplifier provides a differential signal which is proportional to the evoked cardiac response.

5788645, Aug 4, 1998

Jun 3, 1996

8/657389

David K. Swanson - Roseville MN
Graydon Beatty - New Brighton MN
Douglas Lang - Arden Hills MN

Cardiac Pacemakers, Inc. - St. Paul MN

G06F15900

600516

A method and apparatus for processing biological signals on an event basis. An event low pass filter (LPF) is provided which passes variations in event features below an event cut-off value, which is analogous to the time-based cutoff frequency. An event high pass filter (HPF) is provided which passes variations in event features that are above an event-rate cutoff. An event variability detector is provided which determines the variation of a discrete variable from values at prior events. An event discriminator is provided for filtering out contributions of unrelated events that are superimposed on a discrete periodic measurement of interest. In all of these techniques, sampling of a biological signal is performed in coincidence with a biological event which does not occur at a constant frequency. In accordance with another aspect, an algorithm is provided using event-based techniques for discriminating abnormal rhythms from normal sinus rhythm on the basis of atrial rate, ventricular rate, and A-V intervals. An interval conditioning stage is provided for processing intervals of atrial beats, ventricular beats, and atrial to ventricular beats and classifying intervals for each according to an adaptive triple-bin technique.

5342407, Aug 30, 1994

Jul 13, 1992

7/912924

Roger W. Dahl - Andover MN
David K. Swanson - Roseville MN
Stephen J. Hahn - Roseville MN
Douglas J. Lang - Arden Hills MN
John E. Heil - St. Paul MN

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 139

607129

Implantable electrodes for defibrillation are formed of pluralities of electrode segments. Each of the segments is relatively long and narrow. The electrode segments can be parallel and spaced apart from one another a distance at least ten times the nominal width, with one end of each segment mounted to a transverse distal portion of an electrically conductive lead coupling the electrode to a defibrillation pulse generator. Alternatively, segments can branch or radiate outwardly from a common junction. In yet another arrangement, electrode segments are portions of a single conductive path at the distal end of a lead from a pulse generator, arranged in either a spiral configuration or a serpentine configuration which can align electrode segments side by side, parallel and spaced apart. The electrode segments can be formed of composite conductors in the form of titanium ribbons or wires with a sputtered outer layer of platinum, or a silver core in a stainless steel tube, with a platinum layer formed onto the tube. The electrodes are highly compliant yet can provide large effective areas for defibrillation, enabling a transthoracic pulsing arrangement of two electrodes on opposite sides of the heart, implanted subcutaneously outside of the thoracic region.

5111812, May 12, 1992

Jan 23, 1990

7/468739

David K. Swanson - Roseville MN
Roger W. Dahl - Andover MN
Douglas J. Lang - Arden Hills MN

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 139

128419D

A defibrillation electrode for implantation in the region of the heart and for connection to a defibrillation system. The electrode comprises multiple independent conductive segments spaced apart for defining a discharge surface of the electrode. In one embodiment, the electrode comprises a plurality of concentric conductive rings electrically connected together. To smooth the current distribution, the interface impedance of the inner conductive segments is made lower than that of the outer conductive segments. In one embodiment, the impedance is determined by the choice of the conductive material. In another embodiment, the impedance is determined by texturing the surface of the conductive segments. In yet another embodiment, the impedance is determined by the ratio of conductive edges to surface of the conductive segment. The discharge surface region can also take the form of a portion of a cardiac catheter.

5360442, Nov 1, 1994

Jan 4, 1993

7/967361

Roger W. Dahl - Andover MN
David K. Swanson - Roseville MN
Stephen J. Hahn - Roseville MN
Douglas J. Lang - Arden Hills MN
John E. Heil - St. Paul MN

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 105

607129

Implantable electrodes for defibrillation are formed of pluralities of electrode segments. Each of the segments is relatively long and narrow. The electrode segments can be parallel and spaced apart from one another a distance at least ten times the nominal width, with one end of each segment mounted to a transverse distal portion of an electrically conductive lead coupling the electrode to a defibrillation pulse generator. Alternatively, segments can branch or radiate outwardly from a common junction. In yet another arrangement, electrode segments are portions of a single conductive path at the distal end of a lead from a pulse generator, arranged in either a spiral configuration or a serpentine configuration which can align electrode segments side by side, parallel and spaced apart. The electrode segments can be formed of composite conductors in the form of titanium ribbons or wires with a sputtered outer layer of platinum, or a silver core in a stainless steel tube, with a platinum layer formed onto the tube. The electrodes are highly compliant yet can provide large effective areas for defibrillation, enabling a transthoracic pulsing arrangement of two electrodes on opposite sides of the heart, implanted subcutaneously outside of the thoracic region.

5634938, Jun 3, 1997

Oct 25, 1995

8/547845

David K. Swanson - Roseville MN
James P. Nelson - Shoreview MN
Douglas J. Lang - Arden Hills MN

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 139

607 5

An implantable defibrillator/cardioverter which generates a biphasic waveform having a duration of at least 15-80 msec and a small "tilt" between the leading edge and trailing edge voltages of each phase. In one embodiment, two capacitors are connected in parallel to create an effectively large capacitance to generate a slowly decaying waveform. In another embodiment, a high capacitance bipolar capacitor is used, which capacitance is at least 200 microFarads.

5531779, Jul 2, 1996

Jan 24, 1995

8/377494

Roger W. Dahl - Andover MN
Robert W. Wickham - late of Harris MN
David K. Swanson - Roseville MN
David Lipson - Poway CA

Cardiac Pacemakers, Inc. - St. Paul MN

A61N 139

607119

Implantable electrode structures for use in apparatus for applying electrical therapy to a patient's heart in the treatment of arrhythmias such as tachycardias and fibrillations of the heart are herein disclosed. The electrode structures are made in the form of expandable (or self-expanding) intravascular stents for insertion through the patient's vascular system to locations in or adjacent the heart. The electrode structures can be inserted into the great veins by insertion techniques used for intravascular stent applications and provide increased electrode surfaces for discharge of electrical energy through the heart in conjunction with other strategically placed electrodes. The wire filament of the stents may be evenly spaced to form a circumferential array or may be non-uniformly spaced to form an elliptical array.