The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 21, 1993
Filed:
Apr. 17, 1992
John D Wahlstrand, Shoreview, MN (US);
Girard B Borgerding, Minneapolis, MN (US);
Daniel R Greeninger, Coon Rapids, MN (US);
Daniel J Baxter, St. Paul, MN (US);
Medtronic, Inc., Minneapolis, MN (US);
Abstract
A rate-responsive cardiac pacemaker comprising a minute ventilation circuit and an activity circuit. The minute ventilation circuit computes a first target pacing rate as a function of measurements of the patient's pleural blood impedance, and the activity circuit computes a second target pacing rate as a function of measured levels of patient activity. A rate control function establishes a rate-responsive pacing rate based on the first and second target pacing rates. The minute ventilation circuit delta-modulates an analog impedance waveform and maintains short-term and long-term weighted averages of delta-modulator output counts. Variations in the difference between the short-term and long-term weighted average values are determinative of the first target pacing rate. Variations in an activity sensor output signal are determinative of the second target pacing rate. Physician-programmable parameters for the pacemaker include selection of a rate-response setting, upper and lower pacing rate limits, and rate-smoothing attack and decay settings.