Rate responsive pacing using the ventricular gradient

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 the depolarization gradient and a repolarization gradient; sensing the peak of the depolarization gradient; sensing the peak of the repolarization gradient; determining the peak to peak time interval from the depolarization gradient peak to the repolarization gradient peak; storing said peak to peak time interval; comparing said peak to peak time interval with a corresponding peak to peak time interval 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 cardiac event potential is an evoked potential.

Claim 5

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 6

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 peak to peak time intervals are equal, varying the pacing rate in one direction if the peak to peak time interval is less than the prior value, and varying the pacing rate in the opposite direction if the peak to peak time interval is greater than the prior value.

Claim 7

A cardiac pacing method as described in claim 5, in which the controlling step includes the steps of not changing the pacing rate if the compared peak to peak time intervals are equal, increasing the pacing rate if the peak to peak time interval is less than the prior value, and decreasing the pacing rate if the peak to peak time interval is greater than the prior value.

Claim 8

A method as described in claim 6, in which the rate controlling step comprises the following steps: if the peak to peak time interval 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 peak to peak time interval 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 predtermined minimum, then decreasing the pacing rate.

Claim 9

A method as described in claim 6, 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 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 depolarization gradient and a repolarization gradient; sensing the peak of the depolarization gradient; sensing the peak of the repolarization gradient; determining the peak to peak time interval from the depolarization gradient peak to the repolarization gradient peak; comprising said peak to peak time interval with a target value; and controlling the rate of said electrical stimulus pulses in response to said comparison.

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 depolarization gradient and a repolarization gradient; sensing the peak of the depolarization gradient; sensing the peak of the repolarization gradient; determining the peak to peak time interval from the depolarization gradient peak to the repolarization gradient peak; comprising said peak to peak time interval with a target value; and controlling the rate of said electrical stimulus pulses in response to said comparison.

Claim 12

A cardiac pacing method as described in claim 9, in which said cardiac event potential is a natural ventricular event potential.

Claim 13

A cardiac pacing method as described in claim 9, in which said cardiac event potential is an evoked potential.

Claim 14

A cardiac pacing method as described in claim 9, including the step of inhibiting the application of a stimulus pulse if a natural ventricular event is sensed within a predetermined time period.

Claim 15

A cardiac pacing method as described in claim 9, in which the rate controlling step includes the steps of not changing the pacing rate if the compared peak to peak time interval and target value are equal, varying the pacing rate in one direction if the peak to peak time interval is less than the target value, and varying the pacing rate in the opposite direction if the peak to peak time interval is greater than the target value.

Claim 16

A cardiac pacing method as described in claim 13, 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 time interval is less than the target value, and decreasing the pacing rate if the time interval is greater than the target value.

Claim 17

A method as described in claim 14, in which the rate controlling step comprises the following steps: if the time interval 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 time interval is greater than the target value, then determining whether the pacing rate is at a predetermined minimum value, 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 18

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 depolarization gradient and a repolarization gradient; sensing the peak of the depolarization gradient; sensing the peak of the repolarization gradient; determining the peak to peak time interval from the depolarization gradient to the repolarization gradient peak; comparing the peak to peak time interval 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 time interval is less than the target value, and decreasing the pacing rate if the time interval is greater than the target value; if the time interval 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 time interval 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 19

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 depolarization gradient and a repolarization gradient; sensing the peak of the depolarization gradient; sensing the peak of the repolarization gradient; determining the peak to peak time interval from the depolarization gradient to the repolarization gradient peak; comparing the peak to peak time interval 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 time interval is less than the target value, and decreasing the pacing rate if the time interval is greater than the target value; if the time interval 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 time interval 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.