Rate responsive pacing system using the integrated cardiac event potential

Claim 2

A cardiac pacing method which comprises the steps of: applying electrical stimulus pulses to the heart; detecting a cardiac event potential; integrating the detected potential over time to obtain a selected parameter; storing said selected parameter; comparing said selected parameter with a corresponding selected parameter of at least one previous cardiac cycle that has been stored; and controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 3

A cardiac pacing method as described in claim 1, in which said cardiac event potential is a natural ventricular event potential.

Claim 4

A cardiac pacing method as described in claim 1, in which said selected parameter comprises the depolarization gradient magnitude.

Claim 5

A cardiac pacing method as described in claim 3, in which the controlling step includes the steps of not changing the pacing rate if the compared depolarization gradient magnitudes are equal, increasing the pacing rate if the depolarization gradient magnitude is less than the prior value, and decreasing the pacing rate if the depolarization gradient magnitude is greater than the prior value.

Claim 6

A method as described in claim 4, in which the rate controlling step comprises the following steps: if the depolarization gradient magnitude is less than the prior value, then determining if the pacing rate is at a predetermined maximum; and if the pacing rate is at a predetermined maximum, then not changing the pacing rate, but if the pacing rate is less than said predetermined maximum then increasing the pacing rate;; and if the depolarization gradient magnitude is greater than the prior value, then determining whether the pacing rate is at a predetermined minimum value; and if the pacing rate is at a predetermined minimum value, then not changing the pacing rate, but if the pacing rate is greater than said predetermined minimum then decreasing the pacing rate.

Claim 7

A method as described in claim 5, including the step of inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 8

A cardiac pacing method as described in claim 1, including the step of sensing the peak of the integrated cardiac event potential from a base line.

Claim 9

A cardiac pacing method as described in claim 1, including the step of inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 10

A cardiac pacing method as described in claim 1, in which the rate controlling step includes the steps of not changing the pacing rate if the compared selected parameters are equal, varying the pacing rate in one direction if the selected parameter is less than the prior value, and varying the pacing rate in the opposite direction if the selected parameter is greater than the prior value.

Claim 11

A cardiac pacing method which comprises the steps of: applying electrical stimulus pulses to the heart; detecting a cardiac event potential; integrating the detected potential over time to obtain a selected parameter; comparing said selected parameter with a target value; and controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 12

A cardiac pacing method which comprises the steps of: applying electrical stimulus pulses to the heart; detecting a cardiac event potential; integrating the detected potential over time to obtain a selected parameter; comparing said selected parameter with a target value; and controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 13

A cardiac pacing method as described in claim 10, in which said cardiac event potential is a natural ventricular event potential.

Claim 14

A cardiac pacing method as described in claim 10, in which said selected parameter comprises the depolarization gradient magnitude.

Claim 15

A cardiac pacing method as described in claim 12, in which the controlling step includes the steps of not changing the pacing rate if the compared values are equal, increasing the pacing rate if the depolarization gradient magnitude is less than the target value, and decreasing the pacing rate if the depolarization gradient magnitude is greater than the target value.

Claim 16

A method as described in claim 13, in which the rate controlling step comprises the following steps: if the depolarization gradient magnitude is less than the target value, then determining if the pacing rate is at a predetermined maximum; and if the pacing rate is at a predetermined maximum, then not changing the pacing rate, but if the pacing rate is less than said predetermined maximum then increasing the pacing rate; and if the depolarization gradient magnitude is greater than the target value, then determining whether the pacing rate is at a predetermined minimum value; and if the pacing rate is at a predetermined minimum value, then not changing the pacing rate, but if the pacing rate is greater than said predetermined minimum then decreasing the pacing rate.

Claim 17

A cardiac pacing method as described in claim 10, including the step of sensing the peak of the integrated cardiac event potential from a base line.

Claim 18

A cardiac pacing method as described in claim 10, including the step of inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 19

A cardiac pacing method as described in claim 10, in which the rate controlling step includes the steps of not changing the pacing rate if the compared selected parameter and target value are equal, varying the pacing rate in one direction if the selected parameter is less than the target value, and varying the pacing rate in the opposite direction if the selected parameter is greater than the target value. PG,29

Claim 20

A cardiac pacing method which comprises the steps of: applying electrical stimulus pulses to the heart; detecting a cardiac event potential; integrating the detected potential over time; sensing the peak of the integrated cardiac event potential from a base line to obtain the depolarization gradient magnitude; comparing the depolarization gradient magnitude with a target value; controlling the rate of said electrical stimulus pulses in response to said comparison, said controlling step including the steps of not changing the pacing rate if the compared values are equal, increasing the pacing rate if the depolarization gradient magnitude is less than the target value, and decreasing the pacing rate if the depolarization gradient magnitude is greater than the target value; if the depolarization gradient magnitude is less than the target value, then determining if the pacing rate is at a predetermined maximum; and if the pacing rate is at a predetermined maximum, then not changing the pacing rate, but if the pacing rate is less than said predetermined maximum then increasing the pacing rate; and if the depolarization gradient magnitude is greater than the target value, then determining whether the pacing rate is at a predetermined minimum value; and if the pacing rate is at a predetermined minimum value, then not changing the pacing rate, but if the pacing rate is greater than said predetermined minimum then decreasing the pacing rate; and inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 21

A cardiac pacing method which comprises the steps of: applying electrical stimulus pulses to the heart; detecting a cardiac event potential; integrating the detected potential over time; sensing the peak of the integrated cardiac event potential from a base line to obtain the depolarization gradient magnitude; comparing the depolarization gradient magnitude with a target value; controlling the rate of said electrical stimulus pulses in response to said comparison, said controlling step including the steps of not changing the pacing rate if the compared values are equal, increasing the pacing rate if the depolarization gradient magnitude is less than the target value, and decreasing the pacing rate if the depolarization gradient magnitude is greater than the target value; if the depolarization gradient magnitude is less than the target value, then determining if the pacing rate is at a predetermined maximum; and if the pacing rate is at a predetermined maximum, then not changing the pacing rate, but if the pacing rate is less than said predetermined maximum then increasing the pacing rate; and if the depolarization gradient magnitude is greater than the target value, then determining whether the pacing rate is at a predetermined minimum value; and if the pacing rate is at a predetermined minimum value, then not changing the pacing rate, but if the pacing rate is greater than said predetermined minimum then decreasing the pacing rate; and inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 22

Cardiac pacing apparatus which comprises: means for applying electrical stimulus pulses to the heart; means for detecting a cardiac event potential; means for integrating the detected potential over time to obtain a selected parameter; means for storing said selected parameter; means for comparing said selected parameter with a corresponding selected parameter of at least one previous cardiac cycle that has been stored; and means for controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 23

Cardiac pacing apparatus which comprises: means for applying electrical stimulus pulses to the heart; means for detecting a cardiac event potential; means for integrating the detected potential over time to obtain a selected parameter; means for storing said selected parameter; means for comparing said selected parameter with a corresponding selected parameter of at least one previous cardiac cycle that has been stored; and means for controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 24

Cardiac pacing apparatus as described in claim 19, in which said cardiac event potential comprises a natural ventricular event potential.

Claim 25

Cardiac pacing apparatus as described in claim 19, including means for inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 26

Cardiac pacing apparatus as described in claim 19, in which said controlling means includes means for maintaining the pacing rate constant if the compared selected parameters are equal, means for varying the pacing rate in one direction if the selected parameter is less than the prior value, and means for varying the pacing rate in the opposite direction if the selected parameter is greater than the prior value.

Claim 27

Apparatus as described in claim 22, including means for determining if the pacing rate is at a predetermined minimum, means for determining if the pacing rate is at a predetermined maximum, said controlling means being operable to maintain the pacing rate if the pacing rate is at one of a predetermined maximum and a predetermined minimum.

Claim 28

Cardiac pacing apparatus as described in claim 19, wherein said selected parameter comprises the depolarization gradient magnitude.

Claim 29

Cardiac pacing apparatus which comprises: means for applying electrical stimulus pulses to the heart; means for detecting a cardiac event potential; means for integrating the detected potential over time to obtain a selected parameter; means for comparing said selected parameter with a target value; and means for controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 30

Cardiac pacing apparatus which comprises: means for applying electrical stimulus pulses to the heart; means for detecting a cardiac event potential; means for integrating the detected potential over time to obtain a selected parameter; means for comparing said selected parameter with a target value; and means for controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 31

Cardiac pacing apparatus as described in claim 25, in which said cardiac event potential comprises a natural ventricular event potential.

Claim 32

Cardiac pacing apparatus as described in claim 25, including means for inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 33

Cardiac pacing apparatus as described in claim 25, in which said controlling means includes means for maintaining the pacing rate constant if the compared values are equal, means for varying the pacing rate in one direction if the selected parameter is less than the target value, and means for varying the pacing rate in the opposite direction if the selected parameter is greater than the target value.

Claim 34

Apparatus as described in claim 28, including means for determining if the pacing rate is at a predetermined minimum, means for determining if the pacing rate is at a predetermined maximum, said controlling means being operable to maintain the pacing rate if the pacing rate is at one of a predetermined maximum and a predetermined minimum.