Patents by Inventor Ren Zhou

Ren Zhou has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6112119
    Abstract: Two mechanisms work together to adjust two variables independently so that the gain of an input amplifier used to find physiologic signals in an implantable medical device can be automatically adjusted to enhance the signal to noise ratio of the electrical input to said amplifier. The first determines whether there has been too long a time between senses found in the body's electrical input to the amplifier and if true, and no other conditions override that consideration, it adjusts the value of a long term average parameter which is used as a referent parameter to adjust the actual parameter that is used as the referent for making either a threshold level adjustment or gain change, depending on the structure of the particular design's circuitry and/or software. One set of adjustments to the gain referent parameter depends on the relative size of the long term average parameter and the gain referent parameter.
    Type: Grant
    Filed: October 27, 1997
    Date of Patent: August 29, 2000
    Assignee: Medtronic, Inc.
    Inventors: Robert J. Schuelke, James W. Busacker, James D. Reinke, Kevin L. Bright, Russell E. Anderson, Virginia De La Riva, David W. Hoffman, Ren Zhou
  • Patent number: 5893882
    Abstract: A pacemaker provided with a mode switching feature adapted to stabilize ventricular heart rate during atrial fibrillation. In a preferred embodiment of the invention, the device nominally operates in an atrial synchronized pacing mode such as DDD, DDDR, VDD or VDDR. In response to detection of atrial rhythm characteristics consistent with atrial fibrillation, the device switches into a non-atrial synchronized, ventricular rate stabilization pacing mode with the base ventricular pacing rate modulated on a beat by beat basis based upon preceding intrinsic or paced ventricular heartbeat intervals to adjust the pacing interval towards a desired preset rate stabilization target pacing interval which is typically less than the programmed base pacing interval of the device.
    Type: Grant
    Filed: December 17, 1996
    Date of Patent: April 13, 1999
    Assignee: Medtronic, Inc.
    Inventors: David K. Peterson, Thomas L. Jirak, Ren Zhou, Michael R. S. Hill
  • Patent number: 5846263
    Abstract: An implantable pacemaker employing an arrhythmia prevention pacing modality particularly optimized for inclusion in dual chamber pacemakers and anti-arrhythmia devices which include dual chamber pacemakers. When the pacing mode is in effect, the device alters timing of scheduled atrial and/or ventricular pacing pulses in response to depolarizations sensed during the refractory periods and to ventricular depolarizations sensed outside of the pacemaker's A-V escape intervals. The arrhythmia prevention pacing mode is activated and deactivated in conjunction with the operation of arrhythmia detection features which may also be employed by the device to trigger delivery of anti-arrhythmia therapies.
    Type: Grant
    Filed: December 13, 1996
    Date of Patent: December 8, 1998
    Assignee: Medtronic, Inc.
    Inventors: David K. Peterson, Michael R. S. Hill, Ren Zhou, Kathleen A. Prieve
  • Patent number: 5601615
    Abstract: Capture detection and stimulation threshold-measurement methods and apparatus for deriving atrial and ventricular pace pulse (A-pace and V-pace) stimulation energy strength-duration data. In a first atrial and ventricular threshold test regimen for use with patients having intact A-V conduction or first degree AV block, A-pace pulses are delivered at a test escape interval and A-V delay. Atrial loss of capture (ALOC) in response to an A-pace test stimulus is declared by the absence of a detected ventricular depolarization (V-event) in the latter portion of the paced A-V delay interval following the delivery of the A-pace test stimulus. In the ventricular threshold test regimen, a V-pace test stimulus is delivered after a shortened A-V delay. Ventricular loss of capture (VLOC) is declared by the detection of a V-event in the ventricular refractory period of the V-pace test stimulus.
    Type: Grant
    Filed: August 16, 1994
    Date of Patent: February 11, 1997
    Assignee: Medtronic, Inc.
    Inventors: H. T. Markowitz, John C. Stroebel, Ren Zhou, John C. Rueter