Rate smoothing control

Abstract

A rate smoothing function used in implantable pulse generators uses detected triggering events, which cause the rate smoothing function to be activated or deactivated, and detected parameter adjusting events, which cause parameter(s) of the rate smoothing function to be changed. In one example, the activation/deactivation and/or change to the parameters of the rate smoothing function are temporary, and the pre-event state of the rate smoothing function is set to a post-adjusting state, such as after a first time interval. Rate smoothing may be selected, activated or deactivated, or adjusted based on a cardiac signal state, or based on an activity or other physiological sensor signal. The adjusted rate smoothing parameters may include an up-smoothing percentage to limit a speed of pacing rate increase and a down-smoothing percentage to limit a speed of pacing rate drop.

1 . A method for cardiac pacing using an implantable system, the method comprising:
 monitoring a physiologic parameter other than intrinsic electrical cardiac depolarizations using a sensor of the implantable system; and   adjusting a first rate smoothing percentage and a second rate smoothing percentage in response to a parameter adjusting event detected from the physiologic parameter using a control circuit of the implantable system, the first rate smoothing percentage limiting a speed of pacing rate increase, the second rate smoothing percentage limiting a speed of pacing rate drop.   
     
     
         2 . The method of  claim 1 , comprising calculating the first rate smoothing percentage and second rate smoothing percentage using the physiologic parameter. 
     
     
         3 . The method of  claim 1 , further comprising calculating a pacing rate using the physiologic parameter. 
     
     
         4 . The method of  claim 1 , further comprising providing cardiac resynchronization therapy. 
     
     
         5 . The method of  claim 1 , wherein monitoring the physiologic parameter comprises monitoring metabolic need. 
     
     
         6 . The method of  claim 5 , wherein monitoring the physiologic parameter comprises monitoring the physiologic parameter using an accelerometer. 
     
     
         7 . The method of  claim 5 , wherein monitoring the physiologic parameter comprises monitoring the physiologic parameter using a respiratory sensor. 
     
     
         8 . The method of  claim 1 , wherein monitoring the physiologic parameter comprises monitoring heart function. 
     
     
         9 . The method of  claim 8 , wherein monitoring the physiologic parameter comprises monitoring the physiologic parameter using a blood pressure sensor. 
     
     
         10 . The method of  claim 8 , wherein monitoring the physiologic parameter comprises monitoring the physiologic parameter using a cardiac contractility sensor. 
     
     
         11 . The method of  claim 1 , comprising activating or deactivating rate smoothing in response to a triggering event detected from the physiologic parameter using the control circuit of the implantable system. 
     
     
         12 . The method of  claim 1 , wherein the physiologic parameter includes a physical activity, and further comprising:
 translating the physical activity into an activity level;   determining whether the activity level matches a predetermined state of the physiologic parameter by comparing the activity level to one or more predetermined activity levels; and   adjusting the first rate smoothing percentage and the second rate smoothing percentage in response to the activity level matching the predetermined state of the physiologic parameter.   
     
     
         13 . The method of  claim 12 , further comprising activating or deactivating rate smoothing using the first rate smoothing percentage and the second rate smoothing percentage in response to the activity level matching the predetermined state of the physiologic parameter. 
     
     
         14 . The method of  claim 12 , further comprising calculating the first rate smoothing percentage and the second rate smoothing percentage using the physiologic parameter. 
     
     
         15 . The method of  claim 12 , wherein adjusting the first rate smoothing percentage and the second rate smoothing percentage comprises selecting a stored rate smoothing algorithm in response to the activity level matching the predetermined state of the physiologic parameter. 
     
     
         16 . The method of  claim 12 , wherein the first rate smoothing percentage and the second rate smoothing percentage comprise different percentages. 
     
     
         17 . The method of  claim 12 , comprising setting the first rate smoothing percentage and the second rate smoothing percentage to the same value in response to the activity level being below a predetermined activity level of the one or more predetermined activity levels. 
     
     
         18 . The method of  claim 12 , comprising setting the first rate smoothing percentage to a relatively large value and the second rate smoothing percentage to a relatively small value in response to the activity level exceeding a predetermined activity level of the one or more predetermined activity levels. 
     
     
         19 . The method of  claim 1 , wherein adjusting the first rate smoothing percentage and the second rate smoothing percentage comprises adjusting the first rate smoothing percentage and the second rate smoothing percentage for a programmable time interval in response to the activity level matching the predetermined state of the physiologic parameter. 
     
     
         20 . The method of  claim 1 , comprising:
 detecting a trigger event from the physiologic parameter; and   activating or deactivating the rate smoothing using the first rate smoothing percentage and the second rate smoothing percentage in response to a detection of the trigger event.