System and method for systolic interval analysis

Abstract

According to a system or method, information indicative of a cardiac depolarization signal can be obtained. Information indicative of an acoustic signal from an implantable acoustic sensor included as a portion of an implantable therapy device can be obtained. A feature indicative of an R wave can be identified from the information indicative of the cardiac depolarization signal, and a feature indicative of an S2 heart sound can be identified from the information indicative of the acoustic signal. A time interval between an instant corresponding to the feature indicative of the R wave and an instant corresponding to the feature indicative of the S2 heart sound can be determined. Using information about the determined time interval, an adjusted pacing therapy parameter can be provided for use in a pacing therapy to be provided by the implantable therapy device.

1 . (canceled) 
     
     
         2 . A processor-readable medium, comprising instructions that, when performed by a processor circuit, cause the processor circuit to:
 obtain information indicative of a cardiac depolarization signal;   obtain information indicative of an acoustic signal from an implantable acoustic sensor included as a portion of an implantable therapy device;   identify a feature indicative of an R wave from the information indicative of the cardiac depolarization signal;   identify a feature indicative of an S2 heart sound from the information indicative of the acoustic signal;   determine a time interval between an instant corresponding to the feature indicative of the R wave and an instant corresponding to the feature indicative of the S2 heart sound; and   using information about the determined time interval, provide an adjusted pacing therapy parameter for a pacing therapy to be provided by the implantable therapy device.   
     
     
         3 . The processor-readable medium of  claim 2 , wherein the pacing therapy parameter includes an atrioventricular pacing delay (AVD) value. 
     
     
         4 . The processor-readable medium of  claim 2 , wherein the instructions include instructions that cause the processor circuit to:
 obtain information indicative of the cardiac depolarization signal after adjustment of the pacing therapy parameter;   obtain information indicative of the acoustic signal after adjustment of the pacing therapy parameter; and   determine an updated time interval between an instant corresponding to the feature indicative of the R wave and the second instant corresponding to the feature indicative of the S2 heart sound, after adjustment of the pacing therapy parameter.   
     
     
         5 . The processor-readable medium of  claim 4 , wherein the instructions include instructions that cause the processor circuit to compare the updated time interval to a prior-determined time interval to determine whether the updated time interval has increased or decreased with respect to the prior-determined time interval. 
     
     
         6 . The processor-readable medium of  claim 4 , wherein the instructions include instructions that cause the processor circuit to:
 determine multiple updated R-wave-to-S2-heart-sound time intervals corresponding to respective cardiac cycles; and   determine whether the updated R-wave-to-S2-heart-sound time intervals are increasing or decreasing with respect to a prior-determined time interval.   
     
     
         7 . The processor-readable medium of  claim 6 , wherein the instructions include instructions that cause the processor circuit to adjust the pacing therapy parameter to assess a range of pacing therapy parameter values over a duration including the respective cardiac cycles. 
     
     
         8 . The processor-readable medium of  claim 6 , wherein the instructions to obtain the information indicative of the cardiac depolarization signal include instructions that cause the processor circuit to:
 obtain information indicative of the cardiac depolarization signal over multiple cardiac cycles; and   generate an ensemble average of the obtained information indicative the cardiac depolarization over the multiple cardiac cycles; and   wherein the instructions to identify the feature indicative of the R wave from the information indicative of the cardiac depolarization signal include instructions to identify the feature indicative of the R wave in the ensemble average.   
     
     
         9 . The processor-readable medium of  claim 6 , wherein the instructions to obtain the information indicative of the acoustic signal include instructions that cause the processor circuit to:
 obtain information indicative of the acoustic signal over multiple cardiac cycles; and   generate an ensemble average of the obtained information indicative the acoustic signal over the multiple cardiac cycles; and   wherein the instructions to identify the feature indicative of an S2 heart sound from the information indicative of the acoustic signal include instructions to identify the feature indicative the S2 heart sound in the ensemble average.   
     
     
         10 . The processor-readable medium of  claim 2 , wherein the processor circuit is located in an assembly external to a patient. 
     
     
         11 . The processor-readable medium of  claim 10 , wherein the instructions include instructions that cause the processor circuit to transmit the adjusted pacing therapy parameter for the pacing therapy to the implantable therapy device. 
     
     
         12 . The processor-readable medium of  claim 2 , wherein the instructions include instructions that cause the processor circuit to determine an amplitude of information obtained from the acoustic sensor. 
     
     
         13 . The processor-readable medium of  claim 12 , wherein the instructions include instructions that cause the processor circuit to:
 identify a feature indicative of an S1 heart sound in the obtained information indicative the acoustic signal; and   determine an amplitude of the obtained information indicative of the S1 heart sound corresponding to the identified feature indicative of the S1 heart sound.   
     
     
         14 . The processor-readable medium of  claim 13 , wherein the instructions to obtain the information indicative of the acoustic signal include instructions that cause the processor circuit to:
 obtain information indicative of the acoustic signal over multiple cardiac cycles; and   generate an ensemble average of the obtained information indicative the acoustic signal over the multiple cardiac cycles; and   wherein the instructions to identify the feature indicative of an S1 heart sound in the obtained information include instructions to identify the feature indicative the S1 heart sound in the ensemble average.   
     
     
         15 . A system, comprising:
 a cardiac depolarization sensor circuit configured to obtain information indicative of a cardiac depolarization signal;   an acoustic sensor configured to obtain information indicative of an acoustic signal; and   a processor circuit communicatively coupled to the cardiac depolarization sensor circuit and the acoustic sensor, the processor circuit configured to:
 identify a feature indicative of an R wave from the information indicative of the cardiac depolarization signal; 
 identify a feature indicative of an S2 heart sound from the information indicative of the acoustic signal; 
 determine a time interval between an instant corresponding to the feature indicative of the R wave and an instant corresponding to the feature indicative of the S2 heart sound; and 
 using information about the determined time interval, provide using an external telemetry circuit an adjusted pacing therapy parameter for a pacing therapy to be provided by the implantable therapy device. 
   
     
     
         16 . The system of  claim 15 , comprising:
 the implantable therapy device; and   an external assembly comprising the processor circuit;   wherein the implantable therapy device comprises an ensemble averaging circuit and an implantable telemetry circuit;   wherein the cardiac depolarization sensor circuit is included as a portion of the implantable therapy device;   wherein the cardiac depolarization sensor is coupled to the ensemble averaging circuit configured to generate an ensemble average of the obtained information indicative of the acoustic signal over multiple cardiac cycles; and   wherein the implantable telemetry circuit is coupled to the ensemble averaging circuit and configured to transmit the ensemble average of the information indicative of the acoustic signal to the external assembly.   
     
     
         17 . The system of  claim 15 , comprising the implantable therapy device including a pacing therapy circuit;
 wherein the cardiac depolarization sensor circuit and the acoustic sensor are implantable and included as a portion of the implantable therapy device.   
     
     
         18 . The system of claim wherein the pacing therapy parameter includes an atrioventricular pacing delay (AVD) value. 
     
     
         19 . The system of  claim 15 , wherein the processor circuit is configured to:
 obtain information indicative of the cardiac depolarization signal after adjustment of the pacing therapy parameter;   obtain information indicative of the acoustic signal after adjustment of the pacing therapy parameter; and   determine an updated time interval between an instant corresponding to the feature indicative of the R wave and the second instant corresponding to the feature indicative of the S2 heart sound, after adjustment of the pacing therapy parameter.   
     
     
         20 . The system of  claim 1 , wherein the processor circuit is configured to determine an amplitude of information obtained from the acoustic sensor. 
     
     
         21 . A system, comprising:
 an implantable therapy device including:
 a cardiac depolarization sensor circuit confer red to obtain information indicative of a cardiac depolarization signal; 
 an acoustic sensor configured to obtain information indicative of an acoustic signal; 
 a pacing therapy circuit; and 
 an implantable telemetry circuit; and 
   an external assembly including:
 an external telemetry circuit; and 
 a processor circuit communicatively coupled to the cardiac depolarization sensor circuit and the acoustic sensor using the external telemetry circuit, the processor circuit configured to:
 identify a feature indicative of an R wave from the information indicative of the cardiac depolarization signal; 
 identify a feature indicative of S2 heart sound from the information indicative of the acoustic signal; 
 determine a time interval between an instant corresponding to the feature indicative of the R wave and an instant corresponding to the feature indicative of the S2 heart sound; and 
 using information about the determined time interval, provide using an external telemetry circuit an adjusted pacing therapy parameter for a pacing therapy to be provided by the pacing therapy circuit of the implantable therapy device.