Apparatus and method for optimizing atrioventricular delay

Abstract

Systems and methods to optimize atrioventricular delay during sensing or pacing of the atrium and for a plurality of sensed rates or pacing rates. In one example, a paced atrioventricular delay is calculated using a sensed atrioventricular interval and a paced atrioventricular interval. In another example, a plurality of paced atrioventricular delays for different pacing rates can be calculated. In another example embodiment, a plurality of sensed atrioventricular delays for different sensing rates can be calculated. Combinations of the various systems and methods are also possible.

1 . A method for operating a cardiac rhythm management device, comprising:
 delivering cardiac resynchronization therapy with a selected atrioventricular delay, wherein the cardiac resynchronization therapy includes delivering ventricular pacing upon expiration of a selected atrioventricular delay AVD s  after an atrial sense and upon expiration of a selected atrioventricular delay AVD p  after an atrial pace;   sensing and timing a plurality of sensed and paced intrinsic atrioventricular intervals at a plurality of rates, wherein a sensed intrinsic atrioventricular interval is the interval between an atrial sense and a ventricular sense and wherein a paced intrinsic atrioventricular interval is the interval between an atrial pace and a ventricular sense;   calculating a plurality of AVD s  values and AVD p  values for use in delivering resynchronization therapy at different atrial rates based on the plurality of atrioventricular intervals;   calculating a plurality of different AVD s  values for each of a plurality of a sensed atrial rates by: 1) operating in a ventricular pacing mode with atrial sensing but no atrial pacing, 2) when the currently sensed atrial rate corresponds to one of the plurality of sensed atrial rates, calculating and storing an AVD s  value for that sensed atrial rate as a function of the intrinsic atrioventricular interval, 3) storing each calculated AVD s  value with an associated specified expiration interval so that the AVD s  value expires after the expiration interval lapses, 4) when the currently sensed atrial rate corresponds to one of the plurality of sensed atrial rates for which the AVD s  value has been previously calculated but has expired, recalculating and storing the AVD s  value for that sensed atrial rate;   calculating a plurality of different AVD p  values for each of a plurality of a paced atrial rates by: 1) operating in a ventricular pacing mode with atrial pacing, 2) varying the atrial pacing rate to corresponds to each of the plurality of paced atrial rates, and 3) calculating and storing an AVD p  value for each paced atrial rate as a function of the intrinsic atrioventricular interval measured at each particular atrial pacing rate; and,   selecting one of the plurality of stored AVD s  values and AVD p  values for use in delivering cardiac resynchronization pacing based on an interval between atrial beats of consecutive cardiac cycles.   
     
     
         2 . The method of  claim 1 , further comprising selecting one of the plurality of atrioventricular delay values based on a current sensed rate after switching from a ventricular pacing mode with atrial pacing to a ventricular pacing mode with no atrial pacing. 
     
     
         3 . The method of  claim 1 , further comprising selecting one of the plurality of atrioventricular delay values based on a current pacing rate after switching from a ventricular pacing mode with no atrial pacing to a ventricular pacing mode with atrial pacing. 
     
     
         4 . The method of  claim 1 , further comprising selecting pacing the heart at increasing rates, sensing and timing a paced atrioventricular interval at each increased pacing rate, and calculating the plurality of atrioventricular delay values based on the associated paced atrioventricular interval. 
     
     
         5 . The method of  claim 1 , further comprising selecting determining whether a previous value has been calculated or has expired for the plurality of atrioventricular delay values. 
     
     
         6 . The method of  claim 1 , further comprising storing an atrioventricular delay value if the previous value has not been calculated or has expired. 
     
     
         7 . The method of  claim 1 , further comprising selecting between a sensed atrioventricular delay and a paced atrioventricular delay based on a mode in which the cardiac resynchronization device is operating. 
     
     
         8 . The method of  claim 1 , further comprising:
 calculating an AVD s  value for a particular atrial rate as a function of a sensed intrinsic atrioventricular interval AVI s  measured at that particular atrial rate as
   AVD s   =K 1(AVI s )− K 2; and,
 
   calculating an AVD p  value for a particular atrial pacing rate as a function of a paced intrinsic atrioventricular interval AVI p  measured at that particular atrial pacing rate as
   AVD p   =K 1(AVI p )− K 2.
 
   
     
     
         9 . The method of  claim 1 , further comprising increasing the atrial pacing rate through a range of different pacing rates in order to collect paced intrinsic atrioventricular intervals at different atrial pacing rates and calculate corresponding AVD p  values. 
     
     
         10 . The method of  claim 1 , further comprising opportunistically calculating corresponding AVD s  values as atrial senses occur and subsequently increase the atrial pacing rate by a specified amount above the intrinsic atrial rate to calculate an AVD p  value. 
     
     
         11 . A method for operating a cardiac rhythm management device, comprising:
 delivering cardiac resynchronization therapy with a selected atrioventricular delay, wherein the cardiac resynchronization therapy includes delivering ventricular pacing upon expiration of a selected atrioventricular delay AVD s  after an atrial sense and upon expiration of a selected atrioventricular delay AVD p  after an atrial pace;   sensing and timing a plurality of sensed and paced intrinsic atrioventricular intervals at a plurality of rates, wherein a sensed intrinsic atrioventricular interval is the interval between an atrial sense and a ventricular sense and wherein a paced intrinsic atrioventricular interval is the interval between an atrial pace and a ventricular sense;   calculating a plurality of AVD s  values and AVD p  values for use in delivering resynchronization therapy at different atrial rates based on the plurality of atrioventricular intervals;   calculating a plurality of different AVD s  values for each of a plurality of a sensed atrial rates by: 1) operating in a ventricular pacing mode with atrial sensing but no atrial pacing, 2) when the currently sensed atrial rate corresponds to first sensed atrial rate, calculating and storing an AVD s  value for the first sensed atrial rate as a function of the intrinsic atrioventricular interval, 3) when the currently sensed atrial rate corresponds to second sensed atrial rate, calculating and storing an AVD s  value for the second sensed atrial rate as a function of the intrinsic atrioventricular interval, 4) calculating and storing a plurality of AVD s  values by linearly interpolating between the calculated AVD s  values for the first and second sensed atrial rates, 5) storing each calculated AVD s  value with an associated specified expiration interval so that the AVD s  value expires after the expiration interval lapses, 6) when the currently sensed atrial rate corresponds to one of the plurality of sensed atrial rates for which the AVD s  value has been previously calculated but has expired, recalculating and storing the AVD s  value for that sensed atrial rate;   calculating a plurality of different AVD p  values for each of a plurality of a paced atrial rates by: 1) operating in a ventricular pacing mode with atrial pacing, 2) varying the atrial pacing rate to corresponds to each of the plurality of paced atrial rates, and 3) calculating and storing an AVD p  value for each paced atrial rate as a function of the intrinsic atrioventricular interval measured at each particular atrial pacing rate; and,   selecting one of the plurality of stored AVD s  values and AVD p  values for use in delivering cardiac resynchronization pacing based on an interval between atrial beats of consecutive cardiac cycles.   
     
     
         12 . The method of  claim 11 , further comprising selecting one of the plurality of atrioventricular delay values based on a current sensed rate after switching from a ventricular pacing mode with atrial pacing to a ventricular pacing mode with no atrial pacing. 
     
     
         13 . The method of  claim 11 , further comprising selecting one of the plurality of atrioventricular delay values based on a current pacing rate after switching from a ventricular pacing mode with no atrial pacing to a ventricular pacing mode with atrial pacing. 
     
     
         14 . The method of  claim 11 , further comprising selecting pacing the heart at increasing rates, sensing and timing a paced atrioventricular interval at each increased pacing rate, and calculating the plurality of atrioventricular delay values based on the associated paced atrioventricular interval. 
     
     
         15 . The method of  claim 11 , further comprising selecting determining whether a previous value has been calculated or has expired for the plurality of atrioventricular delay values. 
     
     
         16 . The method of  claim 11 , further comprising storing an atrioventricular delay value if the previous value has not been calculated or has expired. 
     
     
         17 . The method of  claim 11 , further comprising selecting between a sensed atrioventricular delay and a paced atrioventricular delay based on a mode in which the cardiac resynchronization device is operating. 
     
     
         18 . The method of  claim 11 , further comprising:
 calculating an AVD s  value for a particular atrial rate as a function of a sensed intrinsic atrioventricular interval AVI s  measured at that particular atrial rate as
   AVD s   =K 1(AVI s )− K 2; and,
 
   calculating an AVD p  value for a particular atrial pacing rate as a function of a paced intrinsic atrioventricular interval AVI p  measured at that particular atrial pacing rate as
   AVD p   =K 1(AVI p )− K 2.
 
   
     
     
         19 . The method of  claim 11 , further comprising increasing the atrial pacing rate through a range of different pacing rates in order to collect paced intrinsic atrioventricular intervals at different atrial pacing rates and calculate corresponding AVD p  values. 
     
     
         20 . The method of  claim 11 , further comprising opportunistically calculating corresponding AVD s  values as atrial senses occur and subsequently increase the atrial pacing rate by a specified amount above the intrinsic atrial rate to calculate an AVD p  value.