US5237992A — Implantable pacemaker providing hysteresis in dua…

Claim 1

Independent Claim 317 words

A dual-chamber programmable pacemaker comprising: (a) timing/control means for defining an atrial escape interval (AEI) and an atrial ventricular delay (AVD); (b) programming means for setting and deriving operating parameters of said pacemaker, including programmed values of said AEI and AVD; (c) sensing means for sensing atrial and ventricular contractions; (d) pulse generating means for generating an atrial stimulation pulse; (e) atrial escape rate hysteresis means for: (1) extending the programmed value of the AEI by a first prescribed amount in response to sensing a natural atrial contraction by said sensing means, and (2) returning the value of the AEI to its programmed value in response to the generation of an atrial stimulation pulse by said pulse generating means, said timing/control means including means for starting the timing out of said AEI following the sensing of a ventricular contraction or the timing out of said AVD, whichever occurs first, and starting the timing out of said AEI following the sensing of an atrial contraction or the timing out of said AEI, whichever occurs first, said pulse generating means further generating said atrial stimulation pulse in response to the timing out of the AEI, whereby atrial stimulation pulses are generated by said dual-chamber pacemaker at a programmed rate determined by the programmed value of the AEI and AVD, and natural atrial contractions are allowed to occur at a rate less than the programmed rate; and (f) atrial-induced AVD hysteresis means for: (1) extending the programmed value of the AVD by a second prescribed amount in response to sensing a natural atrial contraction by said sensing means, said second prescribed amount being less than said first prescribed amount, and shortening the programmed value of the AEI by said second prescribed amount, and (2) returning the value of the extended AVD to its programmed value in response to the generation of an atrial stimulation pulse by said pulse generating means.

Claim 2

Dependent Claim 317 words

A dual-chamber programmable pacemaker comprising: (a) timing/control means for defining an atrial escape interval (AEI) and an atrial ventricular delay (AVD); (b) programming means for setting and deriving operating parameters of said pacemaker, including programmed values of said AEI and AVD; (c) sensing means for sensing atrial and ventricular contractions; (d) pulse generating means for generating an atrial stimulation pulse; (e) atrial escape rate hysteresis means for: (1) extending the programmed value of the AEI by a first prescribed amount in response to sensing a natural atrial contraction by said sensing means, and (2) returning the value of the AEI to its programmed value in response to the generation of an atrial stimulation pulse by said pulse generating means, said timing/control means including means for starting the timing out of said AEI following the sensing of a ventricular contraction or the timing out of said AVD, whichever occurs first, and starting the timing out of said AEI following the sensing of an atrial contraction or the timing out of said AEI, whichever occurs first, said pulse generating means further generating said atrial stimulation pulse in response to the timing out of the AEI, whereby atrial stimulation pulses are generated by said dual-chamber pacemaker at a programmed rate determined by the programmed value of the AEI and AVD, and natural atrial contractions are allowed to occur at a rate less than the programmed rate; and (f) atrial-induced AVD hysteresis means for: (1) extending the programmed value of the AVD by a second prescribed amount in response to sensing a natural atrial contraction by said sensing means, said second prescribed amount being less than said first prescribed amount, and shortening the programmed value of the AEI by said second prescribed amount, and (2) returning the value of the extended AVD to its programmed value in response to the generation of an atrial stimulation pulse by said pulse generating means.

Claim 3

Dependent Claim 120 words

The pacemaker, as set forth in claim 1, wherein said pulse generating means further comprises means for generating a ventricular stimulation pulse, said ventricular stimulation pulse generated at the timing out of the AVD, said pacemaker further including ventricular-induced AVD hysteresis means for: (1) extending the programmed value of the AVD by a third prescribed amount in response to sensing a natural ventricular contraction by said sensing means, said third prescribed amount being less than said first prescribed amount, and shortening the programmed value of the AEI by said third prescribed amount, and (2) returning the value of the extended AVD to its programmed value in response to the generation of a ventricular stimulation pulse by said pulse generating means.

Claim 4

Dependent Claim 65 words

The pacemaker, as set forth in claim 2, wherein said programming means comprises means for selectively enabling and disabling said atrial escape rate hysteresis means, said atrial-induced AVD hysteresis means, and said ventricular-induced AVD hysteresis means, whereby selected combinations of said atrial escape rate hysteresis means, said atrial-induced AVD hysteresis means, and said ventricular-induced AVD hysteresis means may be enabled for use within said pacemaker.

Claim 5

Dependent Claim 69 words

The pacemaker, as set forth in claim 3, further comprising means for combining said atrial-induced AVD hysteresis means and said ventricular-induced AVD hysteresis means when both are enabled through said programming means such that said AVD is extended by the greater of said second prescribed amount or said third prescribed amount, and said AEI is shortened by the greater of said second prescribed amount or said third prescribed amount.

Claim 6

Dependent Claim 117 words

The pacemaker, as set forth in claim 3, further comprising means for combining said atrial-induced AVD hysteresis means and said ventricular-induced AVD hysteresis means when both are enabled through said programming means such that said AVD is first extended by the second or third prescribed amount as a function of whether natural atrial or natural ventricular activity is sensed first, respectively, and is thereafter extended by the greater of said second or third prescribed amount only upon the occurrence of the respective natural atrial or natural ventricular activity corresponding to the greater of said second or third prescribed amounts, and said AEI is shortened by the same second or third prescribed amount used to extend said AVD.

Claim 7

Dependent Claim 60 words

The pacemaker, as set forth in claim 3, wherein said pacemaker further comprises physiological sensing means for sensing a physiological parameter, said physiological parameter providing an indication of the physiological need of a patient, and wherein said timing/control means further comprises means for automatically adjusting said programmed AEI in response to the physiological parameter sensed by said physiological sensing means.

Claim 8

Dependent Claim 63 words

The pacemaker, as set forth in claim 6, wherein said timing/control means comprises a programmable timer that defines a time interval having a duration set by a control variable applied thereto, and wherein said control means applies a first control variable to said programmable timer to define said AEI, and a second control variable to said programmable timer to define an extended AEI.

Claim 9

Dependent Claim 64 words

The pacemaker, as set forth in claim 7, wherein said programmable timer comprises a digital counter and a clock circuit, and wherein said control variable comprises a digital data word that is loaded into said digital counter, the time interval defined by said programmable timer comprising the time it takes said digital data word to be counted by said digital counter and clock circuit.

Claim 10

Dependent Claim 129 words

An implantable pacemaker configured for operation in a dual-chamber pacing mode, said pacemaker comprising: means for sensing natural cardiac activity in the atrium and ventricle of a heart, and means for generating a stimulation pulse for delivery to a selected one of the atrium or ventricle of the heart; timing means for defining an atrial escape interval (AEI) and an atrial ventricular delay (AVD), the sum of said AEI and AVD comprising a first value, said first value setting a pacer rate at which stimulation pulses are provided to the heart; and programmable hysteresis means for selectively extending at least one of said AEI or AVD for so long as natural cardiac activity continues to be sensed in accordance with at least one of a plurality of hysteresis modes.

Claim 11

Dependent Claim 129 words

An implantable pacemaker configured for operation in a dual-chamber pacing mode, said pacemaker comprising: means for sensing natural cardiac activity in the atrium and ventricle of a heart, and means for generating a stimulation pulse for delivery to a selected one of the atrium or ventricle of the heart; timing means for defining an atrial escape interval (AEI) and an atrial ventricular delay (AVD), the sum of said AEI and AVD comprising a first value, said first value setting a pacer rate at which stimulation pulses are provided to the heart; and programmable hysteresis means for selectively extending at least one of said AEI or AVD for so long as natural cardiac activity continues to be sensed in accordance with at least one of a plurality of hysteresis modes.

Claim 12

Dependent Claim 111 words

The implantable pacemaker, as set forth in claim 9, wherein said plurality of hysteresis modes comprises: a first hysteresis mode that causes the AEI to be extended to a new value, AEI P , for so long as natural cardiac activity is sensed in the atrium, with AEI P returning to AEI upon a failure to sense natural cardiac activity in the atrium; and a second hysteresis mode that causes the AVD to be extended to a new value, AVD P , for so long as natural cardiac activity is sensed in the atrium, with AVD P returning to AVD upon a failure to sense natural cardiac activity in the atrium.

Claim 13

Dependent Claim 76 words

The implantable pacemaker, as set forth in claim 10, wherein said second hysteresis mode further causes AEI to be shortened to a new value, AEI X , with the sum of AVD P and AEI X being substantially the same as the sum of AVD and AEI, for so long as natural cardiac activity is sensed in the atrium, with AEI X returning to AEI upon a failure to sense natural cardiac activity in the atrium.

Claim 14

Dependent Claim 64 words

The implantable pacemaker, as set forth in claim 10, wherein said plurality of hysteresis modes further comprises a third hysteresis mode that causes the AVD to be extended to a new value, AVD R , for so long as natural cardiac activity is sensed in the ventricle, with AVD R returning to AVD upon a failure to sense natural cardiac activity in the ventricle.

Claim 15

Dependent Claim 76 words

The implantable pacemaker, as set forth in claim 12, wherein said third hysteresis mode further causes AEI to be shortened to a new value, AEI Y , with the sum of AVD R and AEI Y being substantially the same as the sum of AVD and AEI, for so long as natural cardiac activity is sensed in the ventricle, with AEI Y returning to AEI upon a failure to sense natural cardiac activity in the ventricle.

Claim 16

Dependent Claim 111 words

The implantable pacemaker, as set forth in claim 9, wherein said plurality of hysteresis modes comprises: a first hysteresis mode that causes the AEI to be extended to a new value, AEI P , for so long as natural cardiac activity is sensed in the atrium, with AEI P returning to AEI upon a failure to sense natural cardiac activity in the atrium; and a third hysteresis mode that causes the AVD to be extended to a new value, AVD R , for so long as natural cardiac activity is sensed in the ventricle, with AVD R returning to AVD upon a failure to sense natural cardiac activity in the ventricle.

Claim 17

Dependent Claim 76 words

The implantable pacemaker, as set forth in claim 14, wherein said third hysteresis mode further causes AEI to be shortened to a new value, AEI Y , with the sum of AVD P and AEI Y being substantially the same as the sum of AVD and AEI, for so long as natural cardiac activity is sensed in the ventricle, with AEI Y returning to AEI upon a failure to sense natural cardiac activity in the ventricle.

Claim 18

Dependent Claim 111 words

The implantable pacemaker, as set forth in claim 9, wherein said plurality of hysteresis modes comprises: a second hysteresis mode that causes the AVD to be extended to a new value, AVD P , for so long as natural cardiac activity is sensed in the atrium, with AVD P returning to AVD upon a failure to sense natural cardiac activity in the atrium; and a third hysteresis mode that causes the AVD to be extended to a new value, AVD R , for so long as natural cardiac activity is sensed in the ventricle, with AVD R returning to AVD upon a failure to sense natural cardiac activity in the ventricle.

Claim 19

Dependent Claim 76 words

The implantable pacemaker, as set forth in claim 16 wherein said second hysteresis mode further causes AEI to be shortened to a new value, AEI X , with the sum of AVD P and AEI X being substantially the same as the sum of AVD and AEI, for so long as natural cardiac activity is sensed in the atrium, with AEI X returning to AEI upon a failure to sense natural cardiac activity in the atrium.

Claim 20

Dependent Claim 76 words

The implantable pacemaker, as set forth in claim 16, wherein said third hysteresis mode further causes AEI to be shortened to a new value, AEI Y , with the sum of AVD P and AEI Y being substantially the same as the sum of AVD and AEI, for so long as natural cardiac activity is sensed in the ventricle, with AEI Y returning to AEI upon a failure to sense natural cardiac activity in the ventricle.

Claim 21

Dependent Claim 57 words

The implantable pacemaker, as set forth in claim 9, further comprising physiological sensing means for sensing a physiological parameter indicative of how fast the heart should beat, and wherein said timing means comprises means for selectively defining said first value of said escape interval as a function of the physiological parameter sensed by said physiological sensing means.

Claim 22

Independent Claim 275 words

A method of operating an implantable pacemaker configured for operation in a dual-chamber pacing mode, said pacemaker comprising means for sensing natural cardiac activity in the atrium and ventricle of a heart, and means for generating a stimulation pulse for delivery to a selected one of the atrium or ventricle of the heart, said method comprising the steps of: (a) defining an atrial escape interval (AEI) and an AV delay (AVD), the sum of said AEI and AVD comprising a first value, said first value setting a pacer rate at which stimulation pulses are provided to the heart; and (b) selectively extending at least one of said AEI or AVD for so long as natural cardiac activity continues to be sensed in accordance with at least one of a plurality of hysteresis modes, said plurality of hysteresis modes comprising: (1) a first hysteresis mode that comprises extending AEI to a new value, AEI P , for so long as natural cardiac activity is sensed in the atrium, and returning AEI P to AEI upon a failure to sense natural cardiac activity in the atrium, (2) a second hysteresis mode that comprises extending AVD to a new value, AVD P , for so long as natural cardiac activity is sensed in the atrium, and returning AVD P to AVD upon a failure to sense natural cardiac activity in the atrium, and (3) a third hysteresis mode that comprises extending AVD to a new value, AVD R , for so long as natural cardiac activity is sensed in the ventricle, and returning AVD R to AVD upon a failure to sense natural cardiac activity in the ventricle.

Claim 23

Independent Claim 275 words

A method of operating an implantable pacemaker configured for operation in a dual-chamber pacing mode, said pacemaker comprising means for sensing natural cardiac activity in the atrium and ventricle of a heart, and means for generating a stimulation pulse for delivery to a selected one of the atrium or ventricle of the heart, said method comprising the steps of: (a) defining an atrial escape interval (AEI) and an AV delay (AVD), the sum of said AEI and AVD comprising a first value, said first value setting a pacer rate at which stimulation pulses are provided to the heart; and (b) selectively extending at least one of said AEI or AVD for so long as natural cardiac activity continues to be sensed in accordance with at least one of a plurality of hysteresis modes, said plurality of hysteresis modes comprising: (1) a first hysteresis mode that comprises extending AEI to a new value, AEI P , for so long as natural cardiac activity is sensed in the atrium, and returning AEI P to AEI upon a failure to sense natural cardiac activity in the atrium, (2) a second hysteresis mode that comprises extending AVD to a new value, AVD P , for so long as natural cardiac activity is sensed in the atrium, and returning AVD P to AVD upon a failure to sense natural cardiac activity in the atrium, and (3) a third hysteresis mode that comprises extending AVD to a new value, AVD R , for so long as natural cardiac activity is sensed in the ventricle, and returning AVD R to AVD upon a failure to sense natural cardiac activity in the ventricle.

Claim 24

Dependent Claim 78 words

The method of operating a pacemaker, as set forth in claim 20, wherein said second hysteresis mode further comprises shortening AEI to a new value, AEI X , so that the sum of AVD P and AEI X is substantially the same as the sum of AVD and AEI, for so long as natural cardiac activity is sensed in the atrium, and returning AEI X to AEI upon a failure to sense natural cardiac activity in the atrium.

Claim 25

Dependent Claim 78 words

The method of operating a pacemaker, as set forth in claim 20, wherein said third hysteresis mode further comprises shortening AEI to a new value, AEI Y , so that the sum of AVD R and AEI Y is substantially the same as the sum of AVD and AEI, for so long as natural cardiac activity is sensed in the atrium, and returning AEI Y to AEI upon a failure to sense natural cardiac activity in the atrium.

Claim 26

Dependent Claim 233 words

A dual-chamber programmable pacemaker comprising: (a) timing/control means for defining an atrial escape interval (AEI) and an atrial ventricular delay (AVD); (b) programming means for setting and deriving operating parameters of said pacemaker, including programmed values of said AEI and AVD; (c) sensing means for sensing atrial and ventricular contractions; (d) pulse generating means for generating an atrial stimulation pulse; (e) atrial escape rate hysteresis means for: (1) extending the programmed value of the AEI by a first prescribed amount in response to sensing a natural atrial contraction by said sensing means, and (2) returning the value of the AEI to its programmed value in response to the generation of an atrial stimulation pulse by said pulse generating means, said timing/control means including means for starting the timing out of said AEI following the sensing of a ventricular contraction or the timing out of said AVD, whichever occurs first, and starting the timing out of said AEI following the sensing of an atrial contraction or the timing out of said AEI, whichever occurs first, said pulse generating means further generating said atrial stimulation pulse in response to the timing out of the AEI, whereby atrial stimulation pulses are generated by said dual-chamber pacemaker at a programmed rate determined by the programmed value of the AEI and AVD, and natural atrial contractions are allowed to occur at a rate less than the programmed rate.

Claim 27

Dependent Claim 233 words

A dual-chamber programmable pacemaker comprising: (a) timing/control means for defining an atrial escape interval (AEI) and an atrial ventricular delay (AVD); (b) programming means for setting and deriving operating parameters of said pacemaker, including programmed values of said AEI and AVD; (c) sensing means for sensing atrial and ventricular contractions; (d) pulse generating means for generating an atrial stimulation pulse; (e) atrial escape rate hysteresis means for: (1) extending the programmed value of the AEI by a first prescribed amount in response to sensing a natural atrial contraction by said sensing means, and (2) returning the value of the AEI to its programmed value in response to the generation of an atrial stimulation pulse by said pulse generating means, said timing/control means including means for starting the timing out of said AEI following the sensing of a ventricular contraction or the timing out of said AVD, whichever occurs first, and starting the timing out of said AEI following the sensing of an atrial contraction or the timing out of said AEI, whichever occurs first, said pulse generating means further generating said atrial stimulation pulse in response to the timing out of the AEI, whereby atrial stimulation pulses are generated by said dual-chamber pacemaker at a programmed rate determined by the programmed value of the AEI and AVD, and natural atrial contractions are allowed to occur at a rate less than the programmed rate.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-08-23	1997-02-22	1997-08-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-08-23	2001-02-22	2001-08-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-08-23	2005-02-22	2005-08-24	$7700.00	Window Closed / Lapsed

Implantable pacemaker providing hysteresis in dual-chamber modes

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