System and method for evaluating heart failure using an implantable medical device based on heart rate during patient activity
First Claim
1. A method for evaluating heart failure within a patient using an implantable medical device, the method comprising:
- detecting values representative of patient heart rate and corresponding activity levels for the patient during a period of time when the patient is active;
deriving cardiac fitness values based on heart rate and corresponding activity levels detected during the period of time when the patient is active and based on a predetermined rest heart rate of the patient; and
evaluating heart failure, if any, within the patient based on the cardiac fitness values.
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Abstract
Techniques are provided for detecting and tracking heart failure based on heart rate, rest rate and activity levels. Briefly, histograms are generated based on rest-rate adjusted heart rate values and corresponding activity level values. Heart failure is then detected and tracked based on an analysis of the histogram. In one example, so long as the activity level of the patient exceeds some minimum threshold, the ratio of adjusted heart rate to activity level is periodically calculated and resulting values are stored in a histogram. Each day, the histogram is compared against a previous histogram to detect any overall trend. For example, the centroid of the histogram can be calculated each day with any changes in the centroid values used to track progression of heart failure.
52 Citations
27 Claims
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1. A method for evaluating heart failure within a patient using an implantable medical device, the method comprising:
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detecting values representative of patient heart rate and corresponding activity levels for the patient during a period of time when the patient is active;
deriving cardiac fitness values based on heart rate and corresponding activity levels detected during the period of time when the patient is active and based on a predetermined rest heart rate of the patient; and
evaluating heart failure, if any, within the patient based on the cardiac fitness values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for evaluating heart failure within a patient using an implantable medical device, the method comprising:
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detecting values representative of patient heart rate and corresponding activity levels for the patient during periods of time when the patient is active;
deriving individual cardiac fitness values by calculating ratios of rest-rate adjusted heart rate values to corresponding activity level values for each of a plurality of pairs of heart rate values and corresponding activity level values detected during the periods of time while the patient is active, where rest rate is a predetermined rest heart rate of the patient;
generating a histogram based on the individual cardiac fitness values; and
evaluating the heart failure, if any, within the patient based on a numerical measure of the histogram.
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26. A system for evaluating heart failure within a patient for use with an implantable medical device, the system comprising:
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a detection system operative to detect values representative of heart rate and corresponding activity levels for the patient during a period of time when the patient is active;
a derivation unit operative to derive a cardiac fitness value based on heart rate and corresponding activity levels detected during the period of time when the patient is active and on a predetermined rest heart rate of the patient; and
a heart failure evaluation unit operative to evaluate heart failure, if any, within the patient based on the cardiac fitness values.
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27. A system for detecting the progression of congestive heart failure (CHF) within a patient using an implantable medical device, the comprising:
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means for detecting values representative of heart rate and corresponding activity levels for the patient during a period of time when the patient is active;
means for deriving derive a cardiac fitness value based on heart rate and corresponding activity levels detected during the period of time when the patient is active and on a predetermined rest heart rate of the patient;
means for evaluating heart failure, if any, within the patient based on the cardiac fitness values; and
means for of controlling delivery of therapy in response to the evaluation of heart failure.
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Specification