Algorithm for the automatic determination of optimal AV an VV intervals
First Claim
1. A method for setting an optimal interval between chambers of a heart in a pacing device, the method comprising:
- setting the AV interval to a substantially longer time period than physiologically optimal;
measuring the impedance correpsonding to ventricular volume at a plurality of time points over the AV interval;
determining respiratory impedance contributions associated with the measured impedance;
determining a time of minimal impedance in response to the measured impedance and the determined respiratory impedance contributions; and
setting the AV interval as a function of the time of minimal impedance.
1 Assignment
0 Petitions
Accused Products
Abstract
Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.
-
Citations
54 Claims
-
1. A method for setting an optimal interval between chambers of a heart in a pacing device, the method comprising:
-
setting the AV interval to a substantially longer time period than physiologically optimal; measuring the impedance correpsonding to ventricular volume at a plurality of time points over the AV interval; determining respiratory impedance contributions associated with the measured impedance; determining a time of minimal impedance in response to the measured impedance and the determined respiratory impedance contributions; and setting the AV interval as a function of the time of minimal impedance. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method for setting an optimal interval between chambers of a heart in a pacing device, the method comprising:
-
measuring an impedance corresponding to ventricular volume for at least two points in a cardiac cycle to produce measured impedance data; determining respiratory impedance contributions associated with the measured impedance; calculating an impedance change using the measured impedance data and the determined respiratory impedance contributions; searching for an AV interval causing the largest impedance change, wherein the AV interval searching includes varying the AV interval responsive to the measured impedance change to converge on the largest impedance change; and setting the AV interval in the pacing device to the AV interval causing the largest impedance change. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
-
-
31. A method for setting an optimal right ventricle to left ventricle (VV) pacing interval for use in a pacing device, the method comprising:
-
searching for a VV interval causing the largest cardiac cycle maximum impedance, wherein the VV interval searching includes measuring the impedance in the cardiac cycle corresponding to ventricular volume, determining respiratory impedance contributions associated with the measured impedance, determining the cardiac cycle maximum impedance in response to the measured impedance and the determined respiratory impedance contributions, and varying the paced VV interval responsive to the cardiac cycle maximum impedance to converge on the largest cardiac cycle maximum impedance; and setting the VV interval pacing interval in the pacing device to the VV interval causing the largest cardiac cycle maximum impedance. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38)
-
-
39. A method for setting an optimal pacing interval between chambers of a heart for use in a pacing device, the method comprising:
-
searching for a VV interval causing the largest cardiac cycle impedance change, wherein the VV interval searching includes measuring the impedance in the cardiac cycle corresponding to ventricular volume, determining respiratory impedance contributions associated with the measured impedance, calculating a cardiac cycle impedance change in response to the measured impedance and the determined respiratory impedance contributions, and varying the paced VV interval responsive to the cardiac cycle impedance change to converge on the largest cardiac cycle impedance change; and setting the VV interval pacing interval in the pacing device to about the VV interval causing the largest cardiac cycle impedance change. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
-
-
54. A processor readable medium containing instructions to cause the processor to set an optimal pacing interval between chambers of a heart in a pacing device comprising:
-
means for setting an AV interval to a substantially longer time than physiologically optimal; means for pacing and sensing at least one atrial chamber of a heart; means for measuring impedance corresponding to ventricular volume at multiple times over said AV interval for a plurality of cardiac cycles; means for determining respiratory impedance contributions associated with the measured impedance; means for setting an AV optimal contraction time equal to a time when said impedance is at a minimum in response to the means for measuring impedance and the means for determining respiratory impedance contributions; and means for setting said AV interval equal to said AV optimal contraction time adjusted by a constant.
-
Specification