Patents by Inventor Kenneth M. Riff

Kenneth M. Riff 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: 5441525
    Abstract: A rate-responsive cardiac pacemaker implements a novel scheme which detects incipient vasovagal syncope (or other episodes caused by a vasodepressive or cardioinhibitory disorder) when a) the heart rate drops below a programmable minimum size, and b) the rate after said drop is below a programmable maximum drop ending rate. The pacemaker implements a stability and intervention procedure upon the detection of an episode, in which it ignores transient drops in rate, and paces at a predetermined high rate if the drops are stable. The pacemaker then gradually reduces the pacing rate over a predetermined time to the pre-episodic level. A sleep disable feature disables the vasovagal syncope detection and therapy features during the patient's sleeping hours to reduce or eliminate false positive responses.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: August 15, 1995
    Assignee: Medtronic, Inc.
    Inventors: Michael B. Shelton, Kenneth M. Riff, Michael F. Hess
  • Patent number: 5351696
    Abstract: A method and apparatus for morphologic analysis of an electrical signal, implementable in an implantable device such as a pacemaker, cardioverter, defibrillator or the like. The morphologic analysis uses a phase plane representation of the signal, where the signal and its first derivative are plotted along orthogonal axes. A magnitude signal corresponding to the magnitude component of the trajectory of the phase plane representation is generated and applied to a comparator. The comparator produces an activation signal when the magnitude signal exceeds a predetermined threshold. In response to the activation signal, a quadrant detector selectively applies the magnitude signal to one of four integrators, the selection of one integrator over the others being based at all times upon which quadrant of the phase plane the trajectory is in.
    Type: Grant
    Filed: April 23, 1993
    Date of Patent: October 4, 1994
    Assignee: Medtronic, Inc.
    Inventors: Kenneth M. Riff, Ray S. McDonald, Michael J. German
  • Patent number: 5312453
    Abstract: A rate-responsive cardiac pacemaker in which deceleration of the pacing rate is modulated according to recent patient activity or "work". Based on signals provided from an activity sensor in the pacemaker, the pacemaker maintains and periodically recomputes a work value corresponding to the amount of patient activity detected over time. In response to a decrease in or cessation of detected patient activity, the pacemaker reduces the pacing rate, first at a more rapid deceleration rate, then at a lower deceleration rate, and then once again at a more rapid deceleration rate. The length of time during which the pacing rate is reduced at the lower deceleration rate is modulated according to the work value maintained by the pacemaker.
    Type: Grant
    Filed: May 11, 1992
    Date of Patent: May 17, 1994
    Assignee: Medtronic, Inc.
    Inventors: Michael B. Shelton, William J. Combs, Tommy D. Bennett, Michael R. Tollinger, Kenneth M. Riff
  • Patent number: 5040536
    Abstract: Apparatus and method for detecting changes in the posture of a patient. Two pressure sensors are chronically implanted at different places in the cardiovascular system. One may be positioned in the right heart, for example, and the other placed in the inferior vena cava. The positioning is selected for ease of chronic implantation. However, the positions chosen must be such that the differences in pressure with changes in posture are differentially measurable. The differences in pressure changes sensed at the two positions enable electronic circuitry to determine changes in posture of the patient. These changes in posture may be used to indicate associated physiological changes such as increased or decreased demand on the cardiovascular system or changes in other homeostatic functions.
    Type: Grant
    Filed: January 31, 1990
    Date of Patent: August 20, 1991
    Assignee: Medtronic, Inc.
    Inventor: Kenneth M. Riff