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Rate responsive cardiac pacemaker and method for providing an optimized pacing rate which varies with a patient's physiologic demand

  • US 5,282,839 A
  • Filed: 12/14/1992
  • Issued: 02/01/1994
  • Est. Priority Date: 12/14/1992
  • Status: Expired due to Term
First Claim
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1. A rate responsive cardiac pacemaker for providing an optimized pacing rate of stimulation pulses as a function of at least one selected rate control parameter, each of said rate control parameters having a value which varies as a function of changes in a patient'"'"'s physiologic demand, comprising:

  • (A) sensor means for sensing each of said rate control parameter values and for providing a sensor output representative thereof;

    (B) control means coupled to each of said sensor means, comprising;

    (1) clocking means for setting an optimization period;

    (2) rate response defining means for deriving desired pacing rates for each of said sensor means, each said derived desired pacing rate being increased and decreased as a function of said sensor output corresponding thereto, to define a predetermined rate response function for each of said sensor means, such that for a predetermined change in sensor output for each of said sensor means a corresponding change in said desired pacing rate is provided;

    (3) achievement monitoring means having a predetermined achievement criterion reflective of expected levels of exercise of said patient, for each of said sensor means, for monitoring the relationship between each of said derived desired pacing rates and said achievement criterion corresponding thereto over a predetermined optimization period, and for providing an achievement output indicative of each of said monitored relationships;

    (4) average activity level monitoring means for monitoring an average activity level for said patient, said average activity level corresponding to each of said derived desired pacing rates, and having a predetermined minimum and maximum average activity level reflective of expected levels of exercise of said patient for each of said sensor means, and for monitoring a relationship between each of said derived desired pacing rates and said average activity level corresponding thereto over a predetermined optimization period, and further for providing an average activity level output indicative of each of said monitored relationships;

    (5) output means for generating stimulus pulses at optimized pacing rates as a function of each of said derived desired pacing rates; and

    (6) rate response control means for adjusting each of said rate response functions as a function of each of said achievement and said average activity level output corresponding thereto, such that each of said adjusted rate response functions provides an increased or decreased change in desired pacing rate corresponding to said predetermined change in sensor output for each of said sensor means.

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