Pacemaker with activity-dependent rate limiting
First Claim
1. A pacemaker with activity-dependent rate limiting, comprising:
- electrical sensing circuit means for producing a first control signal indicative of a predetermined electrical activity of a patient'"'"'s heart;
pacing circuit means responsive to an upper rate limit and said first control signal for electrically stimulating said heart at a pacing rate restricted by said upper rate limit; and
control circuit means responsive to an activity signal, from activity sensing circuit means, indicative of a patient'"'"'s level of activity other than said predetermined electrical activity for varying said upper rate limit according to the patient'"'"'s level of activity.
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Accused Products
Abstract
A pacemaker is disclosed with a pacing rate that is restricted within a range defined by variable upper and lower rate limits that change as a function of the patient'"'"'s detected level of activity. An indication such as the nonambient temperature of blood is sensed in the right ventricle of the heart to indicate detected activity level. Other activity indications, such as blood oxygen concentration and body motion, either singly or in combination are also disclosed. A control circuit of the pacemaker varies the upper and lower rate limits according to the patient'"'"'s detected level of activity. The control circuit also varies the atrial and ventricular refractory periods along with the AV delay period in response to detected activity level changes.
205 Citations
38 Claims
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1. A pacemaker with activity-dependent rate limiting, comprising:
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electrical sensing circuit means for producing a first control signal indicative of a predetermined electrical activity of a patient'"'"'s heart; pacing circuit means responsive to an upper rate limit and said first control signal for electrically stimulating said heart at a pacing rate restricted by said upper rate limit; and control circuit means responsive to an activity signal, from activity sensing circuit means, indicative of a patient'"'"'s level of activity other than said predetermined electrical activity for varying said upper rate limit according to the patient'"'"'s level of activity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 32, 33, 34)
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18. A pacemaker with activity-dependent rate limiting, comprising:
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an atrial sensing circuit responsive to electrical activity in an atrium of a patient'"'"'s heart for producing a first control signal indicative of a predetermined atrial electrical activity; a pacing circuit responsive to said first control signal and an upper rate limit for electrically stimulating a ventricle of said heart subsequent to said predetermined atrial electrical activity and at a ventricular pacing rate limited by said upper rate limit; and a control circuit responsive to an activity signal, from activity sensing circuit means, indicative of the patient'"'"'s level of activity and including an upper rate limit control unit for varying said upper rate limit according to the patient'"'"'s level of activity. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An atrioventricular pacemaker with activity-dependent rate limiting, comprising:
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an atrial sensing circuit response to electrical activity in a patient'"'"'s heart for producing a first control signal indicative of an atrial depolarization; an atrial refractory circuit for inhibiting said atrial sensing circuit for an atrial refractory period after said atrial depolarization; an atrial refractory control unit responsive to a blood temperature in said heart indicative of the patient'"'"'s level of activity for varying said atrial refractory period according to the patient'"'"'s level of activity; an upper rate limit control unit responsive to said blood temperature for varying an upper rate limit according to the patient'"'"'s level of activity; a lower rate limit control unit responsive to said blood temperature for varying a lower rate limit according to the patient'"'"'s level of activity; a ventricular sensing circuit responsive to said electrical activity for producing a second control signal indicative of a ventricular depolarization; a ventricular refractory circuit for inhibiting said second sensing circuit for a ventricular refractory period; a ventricular refractory control unit responsive to said blood temperature for varying said ventricular refractory period according to the patient'"'"'s level of activity; a pacing circuit responsive to said first and second control signals for electrically stimulating an atrium and a ventricle of said heart on demand at a pacing rate limited by said upper and lower rate limits; a delay circuit responsive to said first control signal for delaying electrically stimulating said ventricle for a predetermined delay period after said atrial depolarization; and a delay control unit responsive to said blood temperature for varying said delay period according to the patient'"'"'s level of activity.
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30. An atrioventricular pacemaker with activity-dependent rate limiting, comprising:
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first sensing means for sensing electrical activity in a patient'"'"'s heart, said sensing means including means for detecting predetermined electrical activity indicative of a P-wave; second sensing means for sensing a patient'"'"'s level of activity other than said predetermined electrical activity; control circuit means coupled to said second sensing means for generating an upper and a lower rate limit for the patient'"'"'s level of activity; and pacing circuit means for generating a ventricular pulse after a predetermined AV delay period in response to detection of said predetermined electrical activity by said first sensing means, whereby the ventricular pulse rate normally equals the sensed atrial rate, said pacing circuit means including means for limiting the ventricular pulse rate to within a range restricted by said upper and lower rate limits, said control circuit means including means for varying said upper rate limit according to the patient'"'"'s level of activity, whereby the ventricular pulse rate follows the sensed atrial rate up to said upper rate limit determined by the patient'"'"'s cardiac output requirement. - View Dependent Claims (31, 35, 36, 37, 38)
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Specification