Pacemaker system and method for measuring and monitoring cardiac activity and for determining and maintaining capture
First Claim
1. A system for determining atrial capture comprising:
- heart pacing means for generating stimulation pulses;
electrically conductive lead means includinga first electrically conductive electrode connected to said heart pacing means, anda second electrically conductive electrode spaced apart from said first electrode; and
means for sensing atrial capture of said stimulation pulses, said atrial capture sensing means includinga first amplifier connected to receive signals sensed by said first electrode, said first amplifier including first receiving means for receiving only those signals indicative of a naturally occurring or intrinsic atrial P-wave, said first amplifier further having means for generating a first output signal in response to the receipt of a signal by said first receiving means,a second amplifier connected to receive signals sensed by said second electrode, said second amplifier including second receiving means for receiving signals indicative of any atrial P-wave sensed by said second electrode, said second amplifier further having means for generating a second output signal indicative of the sensing of at least a P-wave that occurs in response to a stimulation pulse applied to said first electrode by said heart pacing means, andmeans responsive to the absence of the first output signal and the presence of said second output signal and said heart pacing means for determining whether atrial capture has occurred.
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Accused Products
Abstract
A system for determining P-wave and R-wave capture in response to pacemaker supplied electrical stimuli. One embodiment includes a conventional bipolar atrial lead having a tip electrode, connected to a P-wave pace/sense amplifier and pulse output circuits within an implantable pacemaker, and a ring electrode, spaced apart from the tip electrode, connected to a P-wave sensing EGM amplifier within the pacemaker. The bandpass characteristics of the P-wave pace/sense amplifier allow detection of P-wave frequencies in the absence of atrial stimulation pulses. The bandpass characteristics of the P-wave sensing EGM amplifier allow detection of all electrical frequencies in the atrium within the bandpass chosen. Output signals from these two amplifiers are selectively telemetered to an external receiver, where the occurrence of atrial stimulation pulses and P-waves can be monitored. In operation, if constant time intervals between the monitored atrial stimulation pulses and P-wave occurrences are present, P-wave capture has occurred. In the event of variable time intervals, capture has not occurred and the magnitude of the atrial stimulation pulses can be increased until P-wave capture does occur. An alternative embodiment measures this time differential and makes the stimulation pulse adjustment automatically. Other embodiments use the same manual or automatic systems to determine R-wave capture.
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Citations
42 Claims
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1. A system for determining atrial capture comprising:
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heart pacing means for generating stimulation pulses; electrically conductive lead means including a first electrically conductive electrode connected to said heart pacing means, and a second electrically conductive electrode spaced apart from said first electrode; and means for sensing atrial capture of said stimulation pulses, said atrial capture sensing means including a first amplifier connected to receive signals sensed by said first electrode, said first amplifier including first receiving means for receiving only those signals indicative of a naturally occurring or intrinsic atrial P-wave, said first amplifier further having means for generating a first output signal in response to the receipt of a signal by said first receiving means, a second amplifier connected to receive signals sensed by said second electrode, said second amplifier including second receiving means for receiving signals indicative of any atrial P-wave sensed by said second electrode, said second amplifier further having means for generating a second output signal indicative of the sensing of at least a P-wave that occurs in response to a stimulation pulse applied to said first electrode by said heart pacing means, and means responsive to the absence of the first output signal and the presence of said second output signal and said heart pacing means for determining whether atrial capture has occurred. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. In a heart pacing device including atrial stimulation means for stimulating the atrium of a heart with atrial stimulation pulses, and atrial capture sensing means for sensing atrial capture, a means for maintaining atrial capture comprising:
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means for measuring the time delay between successive atrial stimulation pulses and the resulting P-waves; and means for adjusting the magnitude of the atrial stimulation pulses of said atrial stimulation means until the time delay between successive atrial stimulation pulses and sensed atrial P-waves are equal.
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15. In combination with means for stimulating and means for sensing in the atrium of the heart, a means for indicating the successful stimulation of the atrium comprising:
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comparison means for comparing successive time intervals between the application of stimulation pulses by said stimulating means and sensed electrical activity as sensed by said atrial sensing means; and means responsive to said comparison means for indicating when said successive time intervals are the same.
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16. A system for determining capture in response to pacemaker supplied electrical stimuli comprising:
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first lead means having at its distal end a first exposed electrically conductive electrode, a second exposed electrically conductive electrode spaced apart and electrically isolated from said first electrode, and first and second terminals, near the proximal end of said lead means, electrically connected to said first and second electrodes, respectively, the distal end of said first lead means being positionable in a first chamber of a heart; and pacemaker means comprising first pulse output means for generating stimulation pulses, first connector means electrically connected to said first pulse output means and including means for engagingly receiving said first terminal of said lead means, first sense/pace amplifier means for sensing electrical waves generated by spontaneous cardiac action, the input of said sense/pace amplifier means being electrically connected to said first connector means, second sensing amplifier means for sensing electrical waves generated by spontaneous and stimulated cardiac action, second connector means electrically connected to the input of said second sensing amplifier means and including means for engagingly receiving said second terminal of said lead means, and means for monitoring the output of said first and second sensing amplifier means for the purpose of determining if spontaneous or stimulated cardiac action has occurred and whether capture due to said stimulation pulses has occurred. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An implantable cardiac pacing system comprising:
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atrial lead means having first and second terminals at the lead proximal end, a first electrode at the lead distal end electrically connected to said first terminal, a second electrode near the lead distal end spaced from said first electrode and electrically connected to said second terminal; and pacemaker means comprising first connector means for electrically engaging said first terminal, second connector means for electrically engaging said second terminal, pulse generation means connected to said first connector means for providing an atrial stimulation pulse, P-wave sense/pace amplifier means connected to said first connector means for sensing spontaneous atrial action, P-wave sensing EGM amplifier means connected to said second connector means for sensing spontaneous and stimulated atrial action, and means for monitoring the output of said P-wave sensing EGM amplifier means in the presence of atrial stimulation pulses for the purpose of determining if P-wave capture has occurred. - View Dependent Claims (31, 32, 33, 34)
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35. A method of determining capture of stimulation pulses comprising the steps of:
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sensing electrical activity within a prescribed heart chamber at a location spaced apart from a stimulating location of said prescribed heart chamber; measuring the time delay between the application of a stimulation pulse and a resulting electrical wave, said resulting electrical wave being indicative of a contraction of said prescribed heart chamber; comparing successive time delays between stimulation pulses and the resulting electrical wave; and adjusting the magnitude of the stimulation pulses until said time delays are the same, denoting captured atrial stimulation pulses. - View Dependent Claims (36, 37)
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38. A method of determining the effectiveness of atrial stimulation of a heart, the steps comprising:
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stimulating the atrium with stimulation pulses; sensing atrial P-waves in said heart; measuring the time intervals between the application of a stimulation pulse and a subsequent P-wave; identifying those atrial P-waves which are not of intrinsic origin by comparing the measured time intervals, P-wave capture being present when the measured time intervals are the same; and adjusting the magnitude of the stimulation pulses until atrial P-wave capture occurs.
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39. A method for determining P-wave capture in response to pacemaker supplied atrial electrical stimuli comprising the steps of:
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attaching an atrial lead means having first and second electrodes spaced-apart from each other to a pacemaker, said pacemaker including an atrial stimulation pulse generation means to which said first electrode is electrically connected, and a P-wave sensing EGM amplifier means to which said second electrode is electrically connected; stimulating the atrium with pulses provided by said atrial stimulation pulse generation means; and monitoring the output of said P-wave sensing EGM amplifier means for determining if P-wave capture has been effected by said atrial stimulation pulses. - View Dependent Claims (40)
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41. A method for effecting capture in response to pacemaker supplied electrical stimuli comprising the steps of:
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attaching an lead having first and second electrodes spaced-apart from each other to a pacemaker means, said pacemaker means including a stimulation pulse generation means to which said first electrode is electrically connected, and a stimulated-wave sensing EGM amplifier means to which said second electrode is electrically connected; stimulating a chamber of the heart with pulses provided by said stimulation pulse generation means; measuring the time differential between at least two stimulation pulses and the next-occurring stimulated waves sensed by said EGM amplifier means; determining if the measured time intervals are the same; and increasing the amplitude of said stimulation pulses until the measured time intervals are the same. - View Dependent Claims (42)
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Specification