Generation of diagnostic metrics for use in determining delivery of pacing therapy by a cardiac pacing device

Abstract

A cardiac pacemaker that delivers cardiac pacing therapy that includes delivering the cardiac pacing therapy from a cardiac pacing device, sensing a pacing event from a plurality of electrodes of the pacing device, and sensing an electromechanical signal from an electromechanical sensor of the pacing device. A pre-ejection period is determined in response to the sensed electromechanical signal, and a left ventricular ejection time is determined in response to the sensed electromechanical signal. The pacemaker device performs one or both of adjusting a pacing parameter setting and generating an alert in response to the determined pre-ejection period and the determined left ventricular ejection time.

What is claimed: 
     
         1 . A method of delivering a cardiac pacing therapy, comprising:
 delivering the cardiac pacing therapy from a cardiac pacing device;   sensing a pacing event from a plurality of electrodes of the pacing device;   sensing an electromechanical signal from an electromechanical sensor of the pacing device;   determining a pre-ejection period in response to the sensed electromechanical signal;   determining a left ventricular ejection time in response to the sensed electromechanical signal; and   performing one or both of adjusting a pacing parameter setting and generating an alert in response to the determined pre-ejection period and the determined left ventricular ejection time.   
     
     
         2 . The method of  claim 1 , wherein the electromechanical sensor comprises an accelerometer. 
     
     
         3 . The method of  claim 1 , further comprising:
 determining a maximum of a rectified derivative of the EM signal within a first time window extending a predetermined time period from the sensed pacing event; and   determining a maximum of the EM signal within a second time window extending from a second window start point positioned a predetermined distance from the sensed pacing event, wherein the pre-ejection period is determined in response to a time period extending between the sensed pacing event and the maximum of the rectified derivative of the EM signal, and the left ventricular ejection time is determined in response to a time period extending between the second window start point and the maximum of the EM signal.   
     
     
         4 . The method of  claim 3 , wherein the first window extends approximately 260 ms from the sensed pacing event, the second window start point is positioned approximately 200 ms from the sensed pacing event and the second window extends approximately 600 ms from the second window start point. 
     
     
         5 . The method of  claim 1 , further comprising:
 determining trend data associated with the pre-ejection period, the left ventricular ejection time and a ratio of the pre-ejection period and the left ventricular ejection time for a plurality of the sensed cardiac events;   determining whether the pre-ejection period is increasing;   determining whether the ratio of the pre-ejection period and the left ventricular ejection time is increasing; and   adjusting delivery of the cardiac pacing therapy in response to one of determining the pre-ejection period is increasing and determining the ratio of the pre-ejection period and the left ventricular ejection time is increasing.   
     
     
         6 . The method of  claim 5 , wherein determining whether the pre-ejection period increases comprises one of determining whether the pre-ejection period increases by greater than a predetermined percentage over a predetermined number of days and determining whether the pre-ejection period increases above a predetermined numerical threshold, and wherein determining whether the ratio of the pre-ejection period increases comprises one of determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases by greater than a predetermined percentage over a predetermined number of days and determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases above a predetermined numerical threshold. 
     
     
         7 . The method of  claim 1 , further comprising:
 determining trend data associated with the pre-ejection period, the left ventricular ejection time and a ratio of the pre-ejection period and the left ventricular ejection time for a plurality of the sensed cardiac events;   determining whether the pre-ejection period is increasing;   determining whether the left ventricular ejection time is decreasing;   determining whether the ratio of the pre-ejection period and the left ventricular ejection time is increasing;   determining whether heart failure is indicated in response to determining at least two of the pre-ejection period determined to be increasing, the left ventricular ejection time determined to be decreasing, and the ratio of the pre-ejection period and the left ventricular ejection time determined to be increasing; and   generating an alert in response to heart failure being indicated.   
     
     
         8 . The method of  claim 7 , wherein determining whether the pre-ejection period increases comprises one of determining whether the pre-ejection period increases by greater than a predetermined percentage over a predetermined number of days and determining whether the pre-ejection period increases above a predetermined numerical threshold, wherein determining whether the left ventricular ejection time decreases comprises one of determining whether the left ventricular ejection time decreases by greater than a predetermined percentage over a predetermined number of days and determining whether the left ventricular ejection time decreases above a predetermined numerical threshold, and wherein determining whether the ratio of the pre-ejection period increases comprises one of determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases by greater than a predetermined percentage over a predetermined number of days and determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases above a predetermined numerical threshold. 
     
     
         9 . The method of  claim 1 , further comprising:
 determining trend data associated with the pre-ejection period, the left ventricular ejection time and a ratio of the pre-ejection period and the left ventricular ejection time for a plurality of the sensed cardiac events;   determining whether the pre-ejection period is increasing;   determining whether the left ventricular ejection time is decreasing;   determining whether the ratio of the pre-ejection period and the left ventricular ejection time is increasing;   determining whether heart failure is indicated in response to determining at least two of the pre-ejection period determined to be increasing, the left ventricular ejection time determined to be decreasing, and the ratio of the pre-ejection period and the left ventricular ejection time determined to be increasing;   adjusting delivery of the cardiac pacing therapy in response to one of determining the pre-ejection period is increasing and determining the ratio of the pre-ejection period and the left ventricular ejection time is increasing; and   generating an alert in response to heart failure being indicated.   
     
     
         10 . The method of  claim 9 , wherein determining whether the pre-ejection period increases comprises one of determining whether the pre-ejection period increases by greater than a predetermined percentage over a predetermined number of days and determining whether the pre-ejection period increases above a predetermined numerical threshold, wherein determining whether the left ventricular ejection time decreases comprises one of determining whether the left ventricular ejection time decreases by greater than a predetermined percentage over a predetermined number of days and determining whether the left ventricular ejection time decreases above a predetermined numerical threshold, and wherein determining whether the ratio of the pre-ejection period increases comprises one of determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases by greater than a predetermined percentage over a predetermined number of days and determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases above a predetermined numerical threshold. 
     
     
         11 . The method of  claim 1 , wherein the cardiac pacing device comprises a leadless pacemaker device and the sensed pacing event comprises a ventricular pacing event. 
     
     
         12 . A cardiac pacing device for delivering a cardiac pacing therapy, comprising:
 one or more electrodes for sensing a cardiac event and delivering the pacing therapy;   a sensor for sensing an electromechanical signal; and   a processor configured to determine a pre-ejection period in response to the sensed electromechanical signal, determine a left ventricular ejection time in response to the sensed electromechanical signal, and perform one or both of adjusting a pacing parameter setting and generating an alert in response to the determined pre-ejection period and the determined left ventricular ejection time.   
     
     
         13 . The device of  claim 12 , wherein the sensor comprises an accelerometer. 
     
     
         14 . The device of  claim 12 , wherein the processor is configured to determine a maximum of a rectified derivative of the EM signal within a first time window extending a predetermined time period from the sensed pacing event, and determine a maximum of the EM signal within a second time window extending from a second window start point positioned a predetermined distance from the sensed pacing event, wherein the pre-ejection period is determined in response to a time period extending between the sensed pacing event and the maximum of the rectified derivative of the EM signal, and the left ventricular ejection time is determined in response to a time period extending between the second window start point and the maximum of the EM signal. 
     
     
         15 . The device of  claim 14 , wherein the first window extends approximately 260 ms from the sensed pacing event, the second window start point is positioned approximately 200 ms from the sensed pacing event and the second window extends approximately 600 ms from the second window start point. 
     
     
         16 . The device of  claim 12 , wherein the processor is configured to determine trend data associated with the pre-ejection period, the left ventricular ejection time and a ratio of the pre-ejection period and the left ventricular ejection time for a plurality of the sensed cardiac events, determine whether the pre-ejection period is increasing, determine whether the ratio of the pre-ejection period and the left ventricular ejection time is increasing, and adjust delivery of the cardiac pacing therapy in response to one of determining the pre-ejection period is increasing and determining the ratio of the pre-ejection period and the left ventricular ejection time is increasing. 
     
     
         17 . The device of  claim 16 , wherein determining whether the pre-ejection period increases comprises one of determining whether the pre-ejection period increases by greater than a predetermined percentage over a predetermined number of days and determining whether the pre-ejection period increases above a predetermined numerical threshold, and wherein determining whether the ratio of the pre-ejection period increases comprises one of determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases by greater than a predetermined percentage over a predetermined number of days and determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases above a predetermined numerical threshold. 
     
     
         18 . The device of  claim 12 , wherein the processor is configured to determine trend data associated with the pre-ejection period, the left ventricular ejection time and a ratio of the pre-ejection period and the left ventricular ejection time for a plurality of the sensed cardiac events, determine whether the pre-ejection period is increasing, determine whether the left ventricular ejection time is decreasing, determine whether the ratio of the pre-ejection period and the left ventricular ejection time is increasing, determine whether heart failure is indicated in response to determining at least two of the pre-ejection period determined to be increasing, the left ventricular ejection time determined to be decreasing, and the ratio of the pre-ejection period and the left ventricular ejection time determined to be increasing, and generate an alert in response to heart failure being indicated. 
     
     
         19 . The device of  claim 18 , wherein determining whether the pre-ejection period increases comprises one of determining whether the pre-ejection period increases by greater than a predetermined percentage over a predetermined number of days and determining whether the pre-ejection period increases above a predetermined numerical threshold, wherein determining whether the left ventricular ejection time decreases comprises one of determining whether the left ventricular ejection time decreases by greater than a predetermined percentage over a predetermined number of days and determining whether the left ventricular ejection time decreases above a predetermined numerical threshold, and wherein determining whether the ratio of the pre-ejection period increases comprises one of determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases by greater than a predetermined percentage over a predetermined number of days and determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases above a predetermined numerical threshold. 
     
     
         20 . The device of  claim 12 , wherein the processor is configured to determine trend data associated with the pre-ejection period, the left ventricular ejection time and a ratio of the pre-ejection period and the left ventricular ejection time for a plurality of the sensed cardiac events, determine whether the pre-ejection period is increasing, determine whether the left ventricular ejection time is decreasing; determine whether the ratio of the pre-ejection period and the left ventricular ejection time is increasing, determine whether heart failure is indicated in response to determining at least two of the pre-ejection period determined to be increasing, the left ventricular ejection time determined to be decreasing, and the ratio of the pre-ejection period and the left ventricular ejection time determined to be increasing, adjust delivery of the cardiac pacing therapy in response to one of determining the pre-ejection period is increasing and determining the ratio of the pre-ejection period and the left ventricular ejection time is increasing, and generate an alert in response to heart failure being indicated. 
     
     
         21 . The device of  claim 20 , wherein determining whether the pre-ejection period increases comprises one of determining whether the pre-ejection period increases by greater than a predetermined percentage over a predetermined number of days and determining whether the pre-ejection period increases above a predetermined numerical threshold, wherein determining whether the left ventricular ejection time decreases comprises one of determining whether the left ventricular ejection time decreases by greater than a predetermined percentage over a predetermined number of days and determining whether the left ventricular ejection time decreases above a predetermined numerical threshold, and wherein determining whether the ratio of the pre-ejection period increases comprises one of determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases by greater than a predetermined percentage over a predetermined number of days and determining whether the ratio of the pre-ejection period and the left ventricular ejection time increases above a predetermined numerical threshold. 
     
     
         22 . The device of  claim 12 , wherein the cardiac pacing device comprises a leadless pacemaker device and the sensed pacing event comprises a ventricular pacing event. 
     
     
         23 . A non-transitory computer readable medium storing instructions which cause a cardiac medical device to perform a method comprising:
 delivering the cardiac pacing therapy from a cardiac pacing device;   sensing a pacing event from a plurality of electrodes of the pacing device;   sensing an electromechanical signal from an electromechanical sensor of the pacing device;   determining a pre-ejection period in response to the sensed electromechanical signal;   determining a left ventricular ejection time in response to the sensed electromechanical signal; and   performing one or both of adjusting a pacing parameter setting and generating an alert in response to the determined pre-ejection period and the determined left ventricular ejection time.   
     
     
         24 . A medical device system comprising means to perform the method of any one of  claims 1 - 10 .