Richard T Lu

US Patent:

6493584, Dec 10, 2002

Filed:

Sep 8, 2000

Appl. No.:

09/658051

Inventors:

Richard Lu - Thousand Oaks CA

Assignee:

Pacesetter, Inc. - Sylmar CA

International Classification:

A61N 1362

US Classification:

607 9, 128901, 600515

Abstract:

An implantable cardiac stimulation device discriminates between noise and an arrhythmia sensed in a heart. A first sensing circuit generates a first signal representing electrical activity sensed in a first location of the heart and a second sensing circuit generates a second signal representing electrical activity sensed in a second location of the heart. The first and second locations are spaced apart and located in respective different corresponding chambers or the same chambers of the heart. A comparison circuit then compares the first and second signals to provide a comparison factor. A control circuit then determines from the comparison factor if noise is sensed or if an arrhythmia is being sensed.

US Patent:

6604000, Aug 5, 2003

Filed:

Dec 8, 2000

Appl. No.:

09/732996

Inventors:

Richard Lu - Thousand Oaks CA

Assignee:

Pacesetter, Inc. - Sylmar CA

International Classification:

A61N 1365

US Classification:

607 17, 600513

Abstract:

An apparatus and method for monitoring the patients heart for the presence of ischemia and altering the treatment delivered by an implantable cardiac stimulation device to minimize adverse ischemic effects, e. g. , angina pectoris. Embodiments of the present invention are particularly beneficial when used with a rate responsive cardiac stimulation device. Typically, a rate responsive cardiac stimulation device increases its pacing rate (up to a maximum sensor rate) in response to increases in the patients activity level. The rate of this change is referred to in this patent as the aggressiveness of the rate responsiveness. However, in an ischemic state, the aggressiveness of the rate responsiveness may cause the heart to pace at a rate that exacerbates the ischemic effects. Accordingly, embodiments of the present invention alter the pacing regimen in one or more of the following ways. First, the maximum sensor rate is adaptively decremented in response to a detected ischemic state.

US Patent:

6654639, Nov 25, 2003

Filed:

May 7, 2001

Appl. No.:

09/850560

Inventors:

Richard Lu - Thousand Oaks CA

Assignee:

Pacesetter, Inc. - Sylmar CA

International Classification:

A61N 1365

US Classification:

607 17, 607 14

Abstract:

An apparatus and method for performing multi-chamber anti-tachycardia pacing (ATP) in response to a tachycardia that is of particular use in an implantable cardiac stimulation device. The expected benefits of such a multi-chamber ATP include improved hemodynamic performance and the ability to terminate the tachycardia sooner. Embodiments of the present invention use an intrinsic chamber activation sequence and associated interchamber time delays, preferably automatically detected during a period of time when a pathologic tachycardia is not present, to treat a pathologic tachycardia should it occur. Such a device monitors two or more chambers of the patients heart, i. e. , the controlled chambers, and in the event a tachycardia is detected, the device determines the chamber which originated the tachycardia. The device then calculates anti-tachycardia pacing (ATP) cycle lengths, typically as percentages of the detected tachycardia cycle length of the chamber where the tachycardia originated, and begins pacing the controlled chambers according to the intrinsic chamber activation sequence and interchamber delays (initially synchronized relative to a cardiac signal from the chamber which originated the tachycardia) at the ATP cycle lengths for a predefined period or until the tachycardia ends. Optionally, embodiments of the present invention may additionally include a hemodynamic sensor and may adaptively alter the activation sequence and/or interchamber time delays in response to feedback from the hemodynamic sensor.

US Patent:

6687545, Feb 3, 2004

Filed:

Oct 23, 2001

Appl. No.:

10/000560

Inventors:

Richard Lu - Thousand Oaks CA

Assignee:

Pacesetter, Inc. - Sylmar CA

International Classification:

A61N 1362

US Classification:

607 28

Abstract:

An implantable cardiac stimulation device and method perform reliable, automatic capture verification during bipolar stimulation by eliminating capture verification during a cardiac cycle in which anodal stimulation is detected. Anodal stimulation is detected by the absence of a delay between the bipolar stimulation pulse and an evoked response sensed at the electrode functioning as the anode during stimulation. Automatic capture verification during bipolar stimulation is recommended only if anodal stimulation is not detected at a working stimulation output. During automatic capture verification, if anodal stimulation is detected, a capture threshold test is performed. A change in anodal stimulation threshold indicates a change in capture threshold. Thus, periodic anodal stimulation threshold tests are also performed to predict when a change in capture threshold has occurred. The device avoids adverse effects of anodal stimulation on evoked response detection and provides a method for predicting changes in capture threshold.

US Patent:

6697673, Feb 24, 2004

Filed:

Sep 13, 2001

Appl. No.:

09/952728

Inventors:

Richard Lu - Thousand Oaks CA

Assignee:

Pacesetter, Inc. - Sylmar CA

International Classification:

A61N 1368

US Classification:

607 28

Abstract:

An implantable cardiac stimulation device and associated method to verify capture of a stimulated atrial site by detecting a conducted depolarization at another atrial site or in the opposite atrial chamber. A signal received during an atrial capture detection window is compared to a depolarization signal threshold or to a depolarization signal template in order to verify detection of a conducted depolarization signal as evidence of capture at the stimulated site. By sensing depolarization signal away from the stimulated site, the negative effects of lead polarization normally encountered when detecting an evoked response are avoided.

US Patent:

6795733, Sep 21, 2004

Filed:

Mar 21, 2002

Appl. No.:

10/103605

Inventors:

Richard Lu - Thousand Oaks CA

Assignee:

Pacesetter, Inc. - Sylmar CA

International Classification:

A61N 1368

US Classification:

607 17, 600547, 600508

Abstract:

Methods and systems for switching electrode configurations for measuring the transthoracic impedance of patient are described. Various embodiments provide stimulation devices and methods that can automatically adapt to different minute ventilation electrode configurations. This, in turn, permits minute ventilation functionality to continue, e. g. rate-responsive pacing, in spite of the fact that an electrode configuration has changed. Accordingly, minute ventilation functionality can automatically continue in a adaptive manner when a previously-available electrode configuration is no longer available for minute ventilation functionality.

US Patent:

6885893, Apr 26, 2005

Filed:

Mar 25, 2002

Appl. No.:

10/107680

Inventors:

Richard Lu - Thousand Oaks CA, US

Assignee:

Pacesetter, Inc. - Sylmar CA

International Classification:

A61N001/368

US Classification:

607 28

Abstract:

An implantable cardiac stimulation device and associated method set an atrial capture detection window by verifying that inter-atrial conduction is intact, and then measuring the inter-atrial conduction time. The measured inter-atrial conduction time may then be used for setting the atrial capture detection window. Capture verification of a stimulated atrial site is then implemented by detecting a conducted depolarization at another atrial site or in the opposite atrial chamber. A signal received during an atrial capture detection window is compared to a depolarization signal threshold or to a depolarization signal template in order to verify detection of a conducted depolarization signal as evidence of capture at the stimulated site. By sensing depolarization signal away from the stimulated site, the negative effects of lead polarization normally encountered when detecting an evoked response are avoided.

US Patent:

6907287, Jun 14, 2005

Filed:

Jun 14, 2002

Appl. No.:

10/172393

Inventors:

Gregory C. Bevan - Canyon Country CA, US
Richard Lu - Thousand Oaks CA, US
Harold C. Schloss - Los Angeles CA, US
Joseph J. Florio - La Canada CA, US
Janice Barstad - Eden Prairie MN, US

Assignee:

Packsetter, Inc. - Sylmar CA

International Classification:

A61N001/362

US Classification:

607 14

Abstract:

Systems and methods are provided for collecting enhanced diagnostic information specifically pertaining to overdrive pacing within an implantable cardiac stimulation device and for processing and displaying the enhanced diagnostic information using an external programmer. The enhanced diagnostic information includes one or more of overdrive pacing efficacy, overdrive pacing percentage, overdrive pacing/heart rate histogram data, longest recovery duration, atrial event data, minimum/maximum/average of the overdrive pacing rate, number of paced beats at maximum rate, duration of recovery time from maximum rate, intrinsic rate breakthrough histogram data, and number of rate increases. By tracking and displaying the enhanced diagnostic information, a physician can thereby more effectively and reliably program overdrive pacing control parameters to achieve optimal overdrive pacing performance.