Temperature-based, rate-modulated cardiac therapy apparatus and method
First Claim
1. A temperature-based, rate-modulated cardiac therapy device, comprising:
- means for sensing central venous blood temperature; and
processing means coupled to said sensing means for calculating cardiac rate as a function of temperature conditions, one of said conditions including a dip in central venous blood temperature at the onset of exercise, said processing means includingmeans for calculating a first rate component proportional to the magnitude of said dip; and
means for increasing cardiac rate by said first rate component.
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Abstract
A temperature-based, rate-modulated cardiac pacemaker having means for variably controlling the stimulation rate of the heart according to multiple temperature characteristics of the blood referenced to multiple moving baseline temperatures. A target rate is periodically calculated by obtaining a weighted sum of the following rate components: (1) the magnitude of a decrease in temperature below resting temperature, a first moving baseline, (2) the magnitude of an increase in temperature above a local minimum temperature, a second moving baseline, (3) the magnitude of an increase in the resting baseline above a daily minimum temperature, a third moving baseline, and (4) the absolute value of the rate of change of temperature. The resting temperature is preferably calculated over a longer interval than the local minimum temperature but a much shorter interval than the daily minimum temperature. A positive rate of change of temperature is distinguished from a negative rate of change of temperature and is used differently in the calculation of target rate. The target rate is not directly applied as the new pacing rate but is instead averaged with the previous rate in order to provide smoother transitions between pacing rates. An intermediate rate limit is included in addition to lower and upper rate limits, and rank filtering is employed in the determination of rate components.
57 Citations
73 Claims
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1. A temperature-based, rate-modulated cardiac therapy device, comprising:
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means for sensing central venous blood temperature; and processing means coupled to said sensing means for calculating cardiac rate as a function of temperature conditions, one of said conditions including a dip in central venous blood temperature at the onset of exercise, said processing means including means for calculating a first rate component proportional to the magnitude of said dip; and means for increasing cardiac rate by said first rate component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A temperature-based, rate-modulated cardiac therapy device, comprising:
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means for sensing blood temperature; and processing means coupled to said sensing means for calculating cardiac rate, said processing means including means for increasing cardiac rate by an amount proportional to the magnitude of a dip in blood temperature. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A temperature-based, rate-modulated cardiac therapy device, comprising:
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means for sensing blood temperature; means coupled to said sensing means for determining first, second and third moving baseline temperatures; and processing means coupled to said sensing means for calculating cardiac rate, said processing means including summing means for obtaining a weighted sum of a plurality of the following rate components; the magnitude of a decrease in temperature below said first moving baseline temperature; the magnitude of an increase in temperature above said second moving baseline temperature; the magnitude of an increase in said first moving baseline temperature above said third moving baseline temperature; and the absolute value of the rate of change of temperature. - View Dependent Claims (25, 26, 27, 28)
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29. A temperature-based, rate-modulated cardiac therapy device, comprising:
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means for sensing venous blood temperature; and processing means coupled to said sensing means for calculating cardiac rate, said processing means including means for distinguishing between positive and negative rates of change of temperature; means for calculating a first rate component proportional to the magnitude of a negative rate of change of temperature; means for calculating a second rate component proportional to the magnitude of a positive rate of change of temperature; and means for increasing cardiac rate by said first and second rate components. - View Dependent Claims (30, 31, 32, 33)
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34. A temperature-based, rate-modulated cardiac therapy device, comprising:
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means for sensing venous blood temperature, said sensing means including means for producing a plurality of temperature values per minute; and processing means coupled to said sensing means for calculating cardiac rate in response to diurnal variations and deviations from resting temperature, said processing means including means for deriving a daily minimum temperature from temperature values produced over a 24-hour period; means for detecting temperature deviations from said daily minimum temperature; means for deriving a resting temperature from temperature values produced over an interval less than approximately 12 hours; means for detecting temperature deviations from said resting temperature; and means for combining said temperature deviations. - View Dependent Claims (35, 36, 37, 38)
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39. A temperature-based method of modulating cardiac rate, comprising the steps:
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sensing blood temperature; and calculating a new cardiac rate in response to sensed blood temperature, said calculating step including increasing cardiac rate by an amount proportional to the magnitude of a dip in blood temperature. - View Dependent Claims (40, 41, 42, 43, 44, 45)
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46. A temperature-based method of modulating cardiac rate, comprising the steps:
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sensing blood temperature; determining first, second and third moving baseline temperatures; and calculating a new cardiac rate in response to sensed blood temperature, said calculating step including obtaining a weighted sum of a plurality of the following rate components; the magnitude of a decrease in temperature below said first moving baseline temperature; the magnitude of an increase in temperature above said second moving baseline temperature; the magnitude of an increase in said first moving baseline temperature above said third moving baseline temperature; and the absolute value of the rate of change of temperature. - View Dependent Claims (47, 48, 49, 50)
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51. A temperature-based, rate-modulated cardiac therapy device, comprising:
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sensing means for sensing central venous blood temperature; sampling means coupled to said sensing means for periodically creating indicia of central venous blood temperature; at least one buffer means for storing a plurality of said indicia of central venous blood temperature; processing means coupled to said at least one buffer means for determining a cardiac pacing rate including a first rate component which is a function of the dip in central venous blood temperature which occurs at the onset of exercise, said processing means including means for calculating said first rate component such that it is proportional to the magnitude of said dip in central venous blood temperature; and means for increasing the cardiac pacing rate by said at least one rate component. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A temperature-based, rate-modulated cardiac therapy device, comprising:
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means for sensing venous blood temperature, said sensing means including means for producing a plurality of temperature values per minute; and processing means coupled to said sensing means for calculating cardiac rate in response to deviations between diurnal and resting temperatures, said processing means including means for deriving a daily minimum temperature from temperature values produced over a 24-hour period; means for deriving a resting temperature from temperature values produced over an interval less than approximately 12 hours; and means for deriving deviations between said daily minimum temperature and said resting temperature.
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72. A temperature-based, rate-modulated cardiac therapy device, comprising:
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first sensing means for sensing a physiological state, said first sensing means including second sensing means for sensing venous blood temperature; sampling means coupled to said first sensing means for periodically creating indicia of said blood temperature; at least one buffer means for storing a plurality of said indicia of said blood temperature; processing means coupled to said at least one buffer means for determining a cardiac therapy including a first rate component which is proportional to the magnitude of a dip in said blood temperature. - View Dependent Claims (73)
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Specification