Method and apparatus for temporarily varying a parameter in an implantable medical device

Abstract

A method and apparatus for varying a parameter in an implantable medical device that includes a plurality of electrodes stimulating heart tissue and sensing cardiac signals, a timing and control device controlling the stimulation of heart tissue by the plurality of electrodes and measuring intervals between the sensed cardiac signals, a storage device storing the measured intervals, and a microprocessor. The microprocessor determines heart rate variability in response to the stored intervals, compares the determined heart rate variability to a predetermined target rate profile, adjusts the parameter from a first setting to a second setting different from the first setting in response to the comparing of the determined heart rate variability and the predetermined target rate profile, and adjusts the parameter from the second setting to a termination setting in response to a termination event or expiration of a first predetermined time period.

1 . An implantable medical device, comprising: 
 a plurality of electrodes stimulating heart tissue and sensing cardiac signals;    a timing and control device controlling the stimulation of heart tissue by the plurality of electrodes and measuring intervals between the sensed cardiac signals;    a storage device storing the measured intervals; and    a microprocessor determining heart rate variability in response to the stored intervals, comparing the determined heart rate variability to a predetermined target rate profile, adjusting the parameter from a first setting to a second setting different from the first setting in response to the comparing of the determined heart rate variability and the predetermined target rate profile, and adjusting the parameter from the second setting to a termination setting in response to expiration of a first predetermined time period.    
   
   
       2 . The device of  claim 1 , further comprising a patient activator generating a patient request for adjusting the parameter, wherein the timing and control device generates an indication of a programmed time of day for initiating the pacing rate variation of the present invention, and the microprocessor initiates the adjusting of the parameter in response to receipt of one of the patient request from the patient activator and the indication of the programmed time of day from the timing and control unit.  
   
   
       3 . The device of  claim 1 , wherein the storage device stores a predetermined heart rate profile, and the microprocessor compares the determined heart rate variability to the target rate profile and determines the adjusting of the parameter is appropriate in response to the comparing of the determined heart rate variability to the target rate profile.  
   
   
       4 . The device of  claim 3 , wherein the microprocessor generates a histogram of heart rates having a plurality of corresponding heart rate bins, and determines the adjusting of the parameter is appropriate in response to a percentage of time that heart rates are within one or more of the plurality of heart rate bins.  
   
   
       5 . The device of  claim 3 , wherein the microprocessor generates a histogram of heart rates having a plurality of corresponding heart rate bins, and determines the adjusting of the parameter is appropriate in response to a number of beats within one or more of the plurality of heart rate bins.  
   
   
       6 . The device of  claim 1 , wherein the storage device includes a predetermined heart rate profile, and the microprocessor compares the determined heart rate variability to the target rate profile and determines the adjusting of the parameter is appropriate in response to change in heart rate variability being less than a predetermined value.  
   
   
       7 . The device of  claim 1 , wherein the storage device stores exercise time profiles corresponding to variations in the second setting, and the microprocessor selects a first exercise time profile from the stored exercise time profiles in response to the comparison of the determined heart rate variability to the predetermined target rate profile.  
   
   
       8 . The device of  claim 7 , wherein each of the stored exercise time profiles include an acceleration portion corresponding to adjusting the parameter from the first setting to the second setting, a steady-state portion corresponding to the second setting, and a deceleration portion corresponding to adjusting the parameter from the second setting to the termination setting.  
   
   
       9 . The device of  claim 8 , wherein the first setting corresponds to a predetermined lower pacing rate and the second setting is greater than the predetermined lower pacing rate.  
   
   
       10 . The device of  claim 7 , wherein the microprocessor determines whether the predetermined target rate profile would be exceeded in response to the first exercise time profile, and selects a second exercise time profile from the stored exercise time profiles in response to the predetermined target profile being exceeded.  
   
   
       11 . The device of  claim 1 , wherein the microprocessor adjusts the parameter from the second setting to the termination setting, prior to the first predetermined time period, in response to detecting one of a programming session, a magnet, a cardiac arrhythmia, spontaneous rate greater than the second setting, and rate response greater than the second setting.  
   
   
       12 . The device of  claim 1 , wherein the microprocessor generates a histogram of heart rates and determines, prior to adjusting the parameter from the first setting to the second setting, whether a current generated histogram is consistent with a predetermined number of previously generated histograms.  
   
   
       13 . The device of  claim 8 , wherein the microprocessor determines whether the target rate profile has been reached, repeats adjusting of the parameter from the first setting to the second setting and from the second setting to the termination setting in response to the target rate profile not being reached, and updates one or more of the acceleration portion, the steady state portion, and the deceleration portion in response to the target rate profile being reached.  
   
   
       14 . The device of  claim 1 , wherein the termination setting corresponds to one of a spontaneous rate, a rate response rate, and the first setting.  
   
   
       15 . The device of  claim 7 , further comprising an output device outputting information corresponding to the selected exercise time profiles.  
   
   
       16 . A method for temporarily varying a parameter in an implantable medical device, comprising: 
 determining heart rate variability;    comparing the determined heart rate variability to a predetermined target rate profile;    adjusting the parameter from a first setting to a second setting different from the first setting in response to the comparing of the determined heart rate variability and the predetermined target rate profile; and    adjusting the parameter from the second setting to a termination setting in response to expiration of a first predetermined time period.    
   
   
       17 . The method of  claim 16 , further comprising determining whether to initiate the varying of a parameter in response to one of receipt of a patient activation and an internal indication of a predetermined time of day for initiating the varying of a parameter.  
   
   
       18 . The method of  claim 16 , further comprising determining whether the varying of a parameter is appropriate in response to the comparing the determined heart rate variability to a predetermined target rate profile.  
   
   
       19 . The method of  claim 16 , wherein determining heart rate variability includes generating a histogram of heart rates having a plurality of corresponding heart rate bins.  
   
   
       20 . The method of  claim 19 , further comprising determining whether the varying of a parameter is appropriate in response to the comparing the determined heart rate variability to a predetermined target rate profile, wherein the varying of a parameter is determined to be appropriate in response to a percentage of time that heart rates are within one or more of the plurality of heart rate bins.  
   
   
       21 . The method of  claim 19 , further comprising determining whether the varying of a parameter is appropriate in response to the comparing the determined heart rate variability to a predetermined target rate profile, wherein the varying of a parameter is determined to be appropriate in response to a number of beats within one or more of the plurality of heart rate bins.  
   
   
       22 . The method of  claim 16 , further comprising determining whether the varying of a parameter is appropriate in response to the comparing the determined heart rate variability to a predetermined target rate profile, wherein the varying of a parameter is determined to be appropriate in response to change in heart rate variability being less than a predetermined value.  
   
   
       23 . The method of  claim 16 , further comprising: 
 storing exercise time profiles corresponding to variations in the second setting; and    selecting a first exercise time profile from the stored exercise time profiles in response to the comparing the determined heart rate variability to a predetermined target rate profile.    
   
   
       24 . The method of  claim 23 , wherein each of the stored exercise time profiles include an acceleration portion corresponding to adjusting the parameter from the first setting to the second setting, a steady-state portion corresponding to the first predetermined time period, and a deceleration portion corresponding to adjusting the parameter from the second setting to the termination setting.  
   
   
       25 . The method of  claim 24 , wherein the first setting corresponds to a predetermined lower pacing rate and the second setting is greater than the predetermined lower pacing rate.  
   
   
       26 . The method of  claim 23 , further comprising: 
 determining whether the predetermined target rate profile would be exceeded in response to the first exercise time profile; and    selecting a second exercise time profile from the stored exercise time profiles in response to the predetermined target profile being exceeded.    
   
   
       27 . The method of  claim 16 , further comprising determining whether to adjust the parameter from the second setting to the termination setting prior to the first predetermined time period.  
   
   
       28 . The method of  claim 27 , wherein the parameter is adjusted from the second setting to the termination setting prior to the first predetermined time period in response to one of a programming session, a magnet, a cardiac arrhythmia, spontaneous rate greater than the second setting, and rate response greater than the second setting.  
   
   
       29 . The method of  claim 16 , wherein determining heart rate variability includes generating a histogram of heart rates having a plurality of corresponding heart rate bins, and further comprising, determining, prior to adjusting the parameter from the first setting to the second setting, whether a current generated histogram is consistent with a predetermined number of previously generated histograms.  
   
   
       30 . The method of  claim 24 , further comprising: 
 determining whether the target rate profile has been reached;    repeating adjusting of the parameter from the first setting to the second setting and from the second setting to the termination setting in response to the target rate profile not being reached; and    updating one or more of the acceleration portion, the steady state portion and the deceleration portion in response to the target rate profile being reached.    
   
   
       31 . The method of  claim 16 , wherein the termination setting corresponds to one of a spontaneous rate, a rate response rate, and the first setting.  
   
   
       32 . The method of  claim 23 , further comprising; 
 storing information corresponding to the selected exercise time profile; and    outputting the stored information to an external device.    
   
   
       33 . An implantable medical device, comprising: 
 means for stimulating heart tissue and sensing cardiac signals;    means for controlling timing of the stimulation of heart tissue and measuring intervals between the sensed cardiac signals;    means for determining heart rate variability in response to the stored intervals;    means for comparing the determined heart rate variability to a predetermined target rate profile;    means for adjusting the parameter from a first setting to a second setting different from the first setting in response to the comparing of the determined heart rate variability and the predetermined target rate profile, and adjusting the parameter from the second setting to a termination setting in response to expiration of a first predetermined time period;    means for selecting a first exercise time profile from stored exercise time profiles in response to the comparison of the determined heart rate variability to the predetermined target rate profile, each of the stored exercise time profiles including an acceleration portion corresponding to adjusting the parameter from the first setting to the second setting, a steady-state portion corresponding to the first predetermined time period, and a deceleration portion corresponding to adjusting the parameter from the second setting to the termination setting, wherein the adjusting means adjusts the parameter from the second setting to the termination setting, prior to the first predetermined time period, in response to detecting one of a programming session, a magnet, a cardiac arrhythmia, spontaneous rate greater than the second setting, and rate response greater than the second setting.    
   
   
       34 . The device of  claim 33 , further comprising means for generating a patient request for adjusting the parameter, wherein the controlling means generates an indication of a programmed time of day for initiating the adjusting of the parameter, and the adjusting means initiates adjusting of the parameter in response to one of the patient request and the indication of the programmed time of day for initiating the adjusting of the parameter.  
   
   
       35 . The device of  claim 34 , wherein the determining means generates a histogram of heart rates having a plurality of corresponding heart rate bins, and determines the adjusting of the parameter is appropriate in response to a percentage of time that heart rates are within one or more of the plurality of heart rate bins.  
   
   
       36 . The device of  claim 33 , wherein the determining means generates a histogram of heart rates having a plurality of corresponding heart rate bins, and determines the adjusting of the parameter is appropriate in response to a number of beats within one or more of the plurality of heart rate bins.  
   
   
       37 . The device of  claim 33 , wherein the first setting corresponds to a predetermined lower pacing rate and the second setting is greater than the predetermined lower pacing rate.  
   
   
       38 . The device of  claim 33 , wherein the comparing means determines whether the predetermined target rate profile would be exceeded in response to the first exercise time profile, and selects a second exercise time profile from the stored exercise time profiles in response to the predetermined target profile being exceeded.  
   
   
       39 . The device of  claim 33 , wherein the determining means generates a histogram of heart rates and determines, prior to the adjusting of the parameter from the first setting to the second setting, whether a current generated histogram is consistent with a predetermined number of previously generated histograms.  
   
   
       40 . The device of  claim 33 , wherein the comparing means determines whether the target rate profile has been reached, and the adjusting means repeats adjusting of the parameter from the first setting to the second setting and from the second setting to the termination setting in response to the target rate profile not being reached, and updates one or more of the acceleration portion, the steady state portion and the deceleration portion in response to the target rate profile being reached.  
   
   
       41 . The device of  claim 33 , wherein the termination setting corresponds to one of a spontaneous rate, a rate response rate, and the first setting.  
   
   
       42 . The device of  claim 35 , further comprising means for outputting information corresponding to the selected exercise time profiles.  
   
   
       43 . An implantable medical device, comprising: 
 means for determining heart rate variability;    means for comparing the determined heart rate variability to a predetermined target rate profile;    means for adjusting the parameter from a first setting to a second setting different from the first setting in response to the comparing of the determined heart rate variability and the predetermined target rate profile; and    means for adjusting the parameter from the second setting to a termination setting in response to expiration of a first predetermined time period.    
   
   
       44 . A computer readable medium having computer executable instructions for performing a method comprising: 
 determining heart rate variability;    comparing the determined heart rate variability to a predetermined target rate profile;    adjusting the parameter from a first setting to a second setting different from the first setting in response to the comparing of the determined heart rate variability and the predetermined target rate profile; and    adjusting the parameter from the second setting to a termination setting in response to expiration of a first predetermined time period.