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:
Oct. 08, 1996
Filed:
Nov. 30, 1994
Charles G Yerich, Fridley, MN (US);
William J Combs, Eden Prairie, MN (US);
Karen J Kleckner, New Brighton, MN (US);
Eric J Panken, Minneapolis, MN (US);
Richard S Schallhorn, St. Paul, MN (US);
John D Wahlstrand, Shoreview, MN (US);
Medtronic, Inc., Minneapolis, MN (US);
Abstract
A body-implantable rate-responsive cardiac pacemaker is provided with circuitry for sensing a plurality of physiologic parameters known to be indicative of a patient's metabolic demand for increased cardiac output. In one embodiment, a rate-responsive pacemaker is provided with an activity sensor for detecting the patient's level of physical activity, and is further provided with an impedance sensing circuit for detecting the patient's level of minute ventilation by monitoring cardiac impedance. A rate-response transfer function, implemented by the pacemaker's control circuitry, periodically computes a rate-responsive pacing rate as a function of the outputs from both physiologic sensing circuits. The pacemaker's pacing rate is variable within a rate range defined by predetermined (programmable) upper and lower limits. In the preferred embodiment, the influence of activity sensing and minute ventilation parameters varies in accordance with the current pacing rate. In particular, the influence of activity sensing in rate determination in accordance with the rate-response function is greater than that of minute ventilation, for slower pacing rates, while the influence of minute ventilation sensing dominates over that of activity sensing for higher pacing rates. Rate response operation of the disclosed system is recorded in the form of histogram data stored over a predetermined history time. The relative influence of the activity sensing and minute ventilation sensing on rate determination is periodically scaled or balanced based upon comparison of the histogram data with predetermined desired response data.