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Cardiopulmonary functional status assessment via heart rate response detection by implantable cardiac device

  • US 7,269,458 B2
  • Filed: 08/09/2004
  • Issued: 09/11/2007
  • Est. Priority Date: 08/09/2004
  • Status: Active Grant
First Claim
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1. A cardiac device, comprising:

  • one or more sensing channels for generating intra-cardiac electrogram signals;

    a controller for detecting intrinsic cardiac activity and measuring an intrinsic heart rate from the electrogram signals;

    an activity level sensor interfaced to the controller for measuring a parameter related to a patient'"'"'s level of physical activity;

    wherein the controller is programmed to construct a historical record of activity level versus heart rate, referred to as a heart rate response profile;

    wherein the controller is programmed to compute a heart rate response slope from the heart rate response profile, defined as the ratio of an incremental change in intrinsic rate to an incremental change in measured activity level;

    wherein the controller is programmed to collect periodic maximum heart rates over time and derive a maximum intrinsic heart rate parameter therefrom indicative of the maximum heart rate the patient is able to attain;

    a pacing channel for pacing a cardiac chamber, wherein the controller is programmed to control the delivery of pacing pulses in accordance with a programmed mode; and

    ,wherein the controller is programmed to switch to a rate-adaptive pacing mode if both the heart rate response slope and maximum intrinsic heart rate parameters have decreased below respective predefined limit values.

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