Atrial and ventricular capture detection and threshold-seeking pacemaker
First Claim
1. A dual chamber pacemaker pulse generator for attachment with atrial and ventricular pacing and sensing electrodes said electrodes being for delivering electrical pulses from said generator for pacing and sensing depolarizations of a patient'"'"'s heart in the atrium and the ventricle respectively, said pacing being at adjustable atrial and ventricular pacing pulse energies wherein said generator comprises:
- variable escape interval timing means for establishing an atrial normal rate escape interval;
atrial pace pulse generator means for generating an atrial pace pulse through said atrial pacing electrodes at the end of said atrial normal rate escape interval in the absence of an atrial sensed event signal at a normal pace pulse energy;
atrial sensing means adapted to be coupled through said atrial sense electrodes for generating an atrial sensed event signal in response to a natural depolarization of atrial tissue during at least a major portion of said atrial normal rate escape interval;
atrial-ventricular delay timing means for establishing an A-V delay interval commencing in timed relation to an atrial sensed event signal or an atrial pace pulse and where in relation to a pace pulse said A-V delay interval comprises a first and second temporal portion;
ventricular sensing means adapted to be coupled to said ventricular electrodes for generating a ventricular sensed event signal in response to a depolarization of ventricular tissue;
ventricular pace pulse generator means for generating a ventricular pace pulse at said ventricular electrodes at the end of said A-V delay interval in the absence of a ventricular sensed event signal detected within said A-V delay interval;
atrial stimulation threshold test means for operating said escape interval timing means at atrial pace test escape intervals and for initiating the delivery of an atrial pace test stimulus by said atrial pace pulse generator means at the end of an atrial pace test escape interval operated by said atrial test means at an atrial pace test pulse energy varying from said normal atrial pace pulse energy in an atrial pace test cycle;
atrial capture detection means responsive to said ventricular sensing means for declaring atrial capture following the delivery of an atrial pace test stimulus by the detection of a ventricular sensed event signal in said second temporal portion of the A-V delay interval following the delivery of the atrial pace test stimulus; and
atrial loss of capture detection means responsive to said ventricular sensing means for declaring atrial loss of capture following the delivery of an atrial pace test stimulus by the absence of a ventricular sensed event signal detected in the A-V delay interval.
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Abstract
Capture detection and stimulation threshold-measurement methods and apparatus for deriving atrial and ventricular pace pulse (A-pace and V-pace) stimulation energy strength-duration data. In a first atrial and ventricular threshold test regimen for use with patients having intact A-V conduction or first degree AV block, A-pace pulses are delivered at a test escape interval and A-V delay. Atrial loss of capture (ALOC) in response to an A-pace test stimulus is declared by the absence of a detected ventricular depolarization (V-event) in the latter portion of the paced A-V delay interval following the delivery of the A-pace test stimulus. In the ventricular threshold test regimen, a V-pace test stimulus is delivered after a shortened A-V delay. Ventricular loss of capture (VLOC) is declared by the detection of a V-event in the ventricular refractory period of the V-pace test stimulus. In a second algorithm for use in the atrium or ventricle in patients having regular measured sinus rhythm, premature A-pace or V-pace test stimuli are delivered, and the presence of an A-event or V-event at the end of the measured sinus escape interval is declared to be ALOC or VLOC, respectively. A-pace and V-pace test stimuli are repeated to confirm capture declarations at an energy exceeding the LOC test energy. The atrial and ventricular stimulation threshold data derived by varying both pulse amplitude (strength) and width (duration) is stored in memory for telemetry out and analysis and for use in setting the V-pace and A-pace normal pulse width and amplitude used between successive auto-capture tests in order to conserve battery energy.
217 Citations
37 Claims
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1. A dual chamber pacemaker pulse generator for attachment with atrial and ventricular pacing and sensing electrodes said electrodes being for delivering electrical pulses from said generator for pacing and sensing depolarizations of a patient'"'"'s heart in the atrium and the ventricle respectively, said pacing being at adjustable atrial and ventricular pacing pulse energies wherein said generator comprises:
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variable escape interval timing means for establishing an atrial normal rate escape interval; atrial pace pulse generator means for generating an atrial pace pulse through said atrial pacing electrodes at the end of said atrial normal rate escape interval in the absence of an atrial sensed event signal at a normal pace pulse energy; atrial sensing means adapted to be coupled through said atrial sense electrodes for generating an atrial sensed event signal in response to a natural depolarization of atrial tissue during at least a major portion of said atrial normal rate escape interval; atrial-ventricular delay timing means for establishing an A-V delay interval commencing in timed relation to an atrial sensed event signal or an atrial pace pulse and where in relation to a pace pulse said A-V delay interval comprises a first and second temporal portion; ventricular sensing means adapted to be coupled to said ventricular electrodes for generating a ventricular sensed event signal in response to a depolarization of ventricular tissue; ventricular pace pulse generator means for generating a ventricular pace pulse at said ventricular electrodes at the end of said A-V delay interval in the absence of a ventricular sensed event signal detected within said A-V delay interval; atrial stimulation threshold test means for operating said escape interval timing means at atrial pace test escape intervals and for initiating the delivery of an atrial pace test stimulus by said atrial pace pulse generator means at the end of an atrial pace test escape interval operated by said atrial test means at an atrial pace test pulse energy varying from said normal atrial pace pulse energy in an atrial pace test cycle; atrial capture detection means responsive to said ventricular sensing means for declaring atrial capture following the delivery of an atrial pace test stimulus by the detection of a ventricular sensed event signal in said second temporal portion of the A-V delay interval following the delivery of the atrial pace test stimulus; and atrial loss of capture detection means responsive to said ventricular sensing means for declaring atrial loss of capture following the delivery of an atrial pace test stimulus by the absence of a ventricular sensed event signal detected in the A-V delay interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A dual chamber pacemaker pulse generator for attachment with atrial and ventricular pacing and sensing electrodes said electrodes being for delivering electrical pulses from said generator for pacing and sensing depolarizations of a patient'"'"'s heart in the atrium and the ventricle, respectively, aid pacing being at adjustable atrial and ventricular pacing pulse energies and wherein said generator comprises:
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variable escape interval timing means for establishing an atrial normal rate escape interval and an atrial test escape interval; atrial pace pulse generator means for generating an atrial pace pulse through said atrial pacing electrodes at the end of said atrial normal rate escape interval in the absence of an atrial sensed event signal at a normal pace pulse energy; atrial sensing means adapted to be coupled through said atrial sense electrodes for generating an atrial sensed event signal in response to a natural depolarization of atrial tissue during at least a major portion of said atrial normal rate escape interval; atrial-ventricular delay timing means for establishing an A-V delay interval commencing in timed relation to an atrial sensed event signal or an atrial pace pulse; ventricular sensing means adapted to be coupled through said ventricular sense electrodes for generating a ventricular sensed event signal ventricular pace pulse generator means for generating a ventricular pace pulse through said ventricular pacing electrodes at the end of said A-V delay interval in the absence of a ventricular sensed event signal detected within said A-V delay interval; means for establishing a ventricular refractory period time interval following delivery of a ventricular pace pulse; ventricular stimulation threshold test means periodically operable for initiating a ventricular stimulation threshold test further comprising; means for operating said escape interval timing means at atrial pace test escape intervals and said atrial-ventricular delay timing means at a test A-V delay interval commencing in timed relation to the delivery of an atrial pace pulse; means for operating said atrial pace pulse generator means to generate an atrial pace pulse at the end of the atrial pace test escape interval at an atrial pace pulse energy sufficient to ensure that atrial capture is achieved and that a conducted ventricular depolarization follows outside said test A-V delay interval; and means for initiating the delivery of a ventricular pace test stimulus by said ventricular pace pulse generator means at the end of said test A-V delay interval which is timed to render the patient'"'"'s ventricle refractory to potential subsequent intrinsically conducted depolarization stimulus captures and depolarizes the ventricle; and ventricular capture detection means responsive to said ventricular sensing means for declaring ventricular capture by the absence of a ventricular sensed event signal in the ventricular refractory period following delivery of the ventricular pace test stimulus. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A dual chamber pacemaker implantable pulse generator for attachment with atrial and ventricular pacing and sensing electrodes said electrodes being for delivering electrical pulses from said generator for pacing and sensing depolarization of a patient'"'"'s heart in the atrium and the ventricle respectively, said being at adjustable atrial and ventricular pacing pulse energies, said generator comprising:
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variable escape interval timing means for establishing a normal atrial rate escape interval; atrial pace pulse generator means for generating an atrial pace pulse through said atrial pacing electrodes at the end of said normal atrial rate escape interval in the absence of an atrial sensed event signal at a normal pace pulse energy; atrial sensing means adapted to be coupled through said atrial sense electrodes for generating an atrial sensed event signal in response to a natural depolarization of atrial tissue during at least a major portion of said normal atrial rate escape interval; atrial-ventricular delay timing means for establishing an A-V delay interval commencing in timed relation to an atrial sensed event signal or an atrial pace pulse and where in relation to a pace pulse said A-V delay interval comprises a first and second temporal portion; ventricular sensing means adapted to be coupled to said ventricular electrodes for generating a ventricular sensed event signal in response to a depolarization of ventricular tissue; ventricular pace pulse generator means for generating a ventricular pace pulse at said ventricular electrodes at the end of said A-V delay interval in the absence of a ventricular sensed event signal detected within said A-V delay interval; means for establishing a ventricular refractory period time interval following delivery of a ventricular pace pulse; pace test stimulus by the presence of a ventricular sensed event signal detected within the ventricular refractory period; and ventricular capture detection means responsive to said ventricular sensing means for declaring ventricular capture by the absence of a ventricular sensed event signal in the ventricular refractory period following delivery of the ventricular pace test stimulus; and means for periodically triggering the operation of said atrial and ventricular stimulation threshold test means in a predetermined sequence of successive test pacing cycles to derive atrial and ventricular stimulation threshold test data related to the declarations of atrial and ventricular capture and loss of capture. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33)
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34. In a pacemaker pulse generator having atrial and ventricular pulse generators for generating and applying atrial and ventricular pacing pulses to the atrium and ventricle of the heart separated by an A-V delay interval to evoke stimulated atrial and ventricular depolarizations and capture the atrium and ventricle and a ventricular sense amplifier for sensing natural depolarizations of the ventricle, a method of testing for the stimulation threshold energy of the ventricle comprising the steps of:
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determining the patient'"'"'s atrial escape interval; operating said atrial pulse generator to deliver an atrial pace pulse at an energy sufficient to capture the atrium when said atrial escape interval times out; setting a test pace A-V delay interval; operating said ventricular pulse generator to deliver a ventricular test stimulus at the end of said test pace A-V delay interval; setting a ventricular sense time window; operating said ventricular sense amplifier during said ventricular sense time window to sense a depolarization of the ventricle; declaring capture of the ventricle by the ventricular test stimulus if a depolarization of the ventricle is not sensed in the ventricular sense time window; and declaring loss of capture of the ventricle by the ventricular test stimulus if a depolarization of the ventricle is sensed in the ventricular sense time window.
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35. In a pacemaker pulse generator having an atrial pulse generator for generating and applying atrial pacing pulses to the atrium of the heart to evoke a stimulated depolarization and capture the atrium and a ventricular sense amplifier for sensing natural depolarizations of the ventricle, apparatus for testing for the stimulation threshold energy of the atrium comprising:
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means for determining the patient'"'"'s atrial escape interval; means for operating said atrial pulse generator to deliver an atrial test pulse at a test energy to the atrium in the atrial escape interval timed to capture the atrium if the test energy is sufficient to capture the atrium after said atrial escape interval times out; means for setting a paced A-V delay interval beginning after a PVC blanking period following said atrial test pulse; means for operating the ventricular sense amplifier during at least the paced A-V delay interval to sense a depolarization of the ventricle; means for declaring capture of the atrium by the atrial test pacing pulse if a depolarization of the ventricle is sensed in the paced A-V delay interval; and means for declaring loss of capture of the atrium by the atrial test pacing pulse if a depolarization of the ventricle is not sensed in the paced A-V delay interval.
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36. In a pacemaker pulse generator having atrial and ventricular pulse generators for generating and applying atrial and ventricular pacing pulses to the atrium and ventricle of the heart separated by an A-V delay interval to evoke stimulated atrial and ventricular depolarizations and capture the atrium and ventricle and a ventricular sense amplifier for sensing natural depolarizations of the ventricle, apparatus for testing for the stimulation threshold energy of the ventricle comprising:
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means for determining the patient'"'"'s atrial escape interval; means for operating said atrial pulse generator to deliver an atrial pace pulse at an energy sufficient to capture the atrium after said atrial escape interval times out; means for setting a test pace A-V delay interval; means for operating said ventricular pulse generator to deliver a ventricular test stimulus at the end of said test pace A-V delay interval; means for setting a ventricular sense time window; means for operating said ventricular sense amplifier during said ventricular sense time window to sense a depolarization of the ventricle; means for declaring capture of the ventricle by the ventricular test stimulus if a depolarization of the ventricle is not sensed in the ventricular sense time window; and means for declaring loss of capture of the ventricle by the ventricular test stimulus if a depolarization of the ventricle is sensed in the ventricular sense time window.
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37. An apparatus comprising a dual chamber pacemaker pulse generator for attachment with atrial and ventricular sensing and pacing electrodes to an atrial and ventricular chamber of a patient'"'"'s heart, respectively and having means for detecting capture during that refractory period which follows the delivery of a pacing pulse in one of said chambers by sensing depolarizations of tissue in the other of said chambers and having timing means for excluding sensed depolarizations too close in time to the delivery of a pacing pulse in said one chamber.
Specification