Ambulatory monitoring of physiologic response to valsalva maneuver

Abstract

Systems and methods for monitoring physiologic response to Valsalva maneuver (VM) are disclosed. An exemplary patient monitor may detect a natural incidence of a VM session occurred in an ambulatory setting using a heart sound (HS) signal sensed from the patient. The patient monitor may include a physiologic response analyzer to sense patient physiologic response during the detected VM session, and generate a cardiovascular or autonomic function indicator based on the sensed physiologic response to the VM. Using the physiologic response to the VM, the system may detect a target physiologic event using the sensed physiologic response to the VM.

What is claimed is: 
     
         1 . A medical-device system, comprising:
 a Valsalva maneuver (VM) detector circuit configured to detect a VM session using a heart sound signal sensed from a patient; and   a physiologic event detector circuit configured to generate a diastolic function indictor using physiologic information sensed from the patient during the detected VM session, and to detect a worsening heart failure (WHF) event based at least in part on the generated diastolic function indictor.   
     
     
         2 . The medical-device system of  claim 1 , wherein the physiologic event detector circuit is configured to determine a heart sound component using the sensed heart sound signal, and to generate the diastolic function indictor using the determined heart sound component. 
     
     
         3 . The medical-device system of  claim 2 , wherein the determined heart sound component includes an S3 intensity. 
     
     
         4 . The medical-device system of  claim 3 , wherein the physiologic event detector circuit is configured to detect the WHF event in response to the S3 intensity exceeding a reference S3 intensity by a specific margin. 
     
     
         5 . The medical-device system of  claim 2 , wherein the determined heart sound component includes a combination of an S3 intensity and an S4 intensity. 
     
     
         6 . The medical-device system of  claim 5 , wherein the determined heart sound component includes a ratio of the S3 intensity to the S4 intensity, 
 wherein the physiologic event detector circuit is configured to determine an indicator of impaired diastolic function in response to the determined ratio of the S3 intensity to the S4 intensity falling below a first threshold value lower than a baseline value range, and to detect the WHF event based at least in part on the impaired diastolic function.   
     
     
         7 . The medical-device system of  claim 5 , wherein the physiologic event detector circuit is configured to determine an indicator of restrictive ventricular filling in response to the determined ratio of the S3 intensity to the S4 intensity exceeding a second threshold value greater than a baseline value range, and to detect the WHF event based at least in part on the restrictive ventricular filling. 
     
     
         8 . The medical-device system of  claim 2 , wherein the determined heart sound component includes a cardiac timing parameter including at least one of:
 a pre-ejection period;   a systolic timing interval;   a left-ventricular ejection time; or   a diastolic timing interval.   
     
     
         9 . The medical-device system of  claim 1 , wherein the VM detector circuit is configured to determine one or more VM phases using the sensed heart sound signal,
 wherein the physiologic event detector circuit is configured to generate the diastolic function indictor during at least one of the determined one or more VM phases.   
     
     
         10 . The medical-device system of  claim 9 , wherein the VM detector circuit is configured to determine the one or more VM phases using an increase or decrease trend of one or more of an S1 intensity, an S2 intensity, an S3 intensity, or an S4 intensity. 
     
     
         11 . The medical-device system of  claim 1 , further comprising a therapy circuit configured to initiate or adjust a therapy to the patient in response to the detection of the WHF event. 
     
     
         12 . A method detecting a cardiac event in a patient, the method comprising:
 detecting, using a Valsalva maneuver (VM) detector circuit, a VM session using a heart sound signal sensed from the patient;   generating, using a physiologic event detector circuit, a diastolic function indictor using physiologic information sensed from the patient during the detected VM session; and   detecting a worsening heart failure (WHF) event based at least in part on the generated diastolic function indictor.   
     
     
         13 . The method of  claim 12 , comprising determining a heart sound component using the sensed heart sound signal,
 wherein generating the diastolic function indictor includes using the determined heart sound component.   
     
     
         14 . The method of  claim 13 , wherein the determined heart sound component includes an S3 intensity,
 wherein detecting the WHF event is in response to the S3 intensity exceeding a reference S3 intensity by a specific margin.   
     
     
         15 . The method of  claim 13 , wherein the determined heart sound component includes a ratio of an S3 intensity to an S4 intensity, and
 wherein generating the diastolic function indictor includes determining an indicator of impaired diastolic function in response to the determined ratio of the S3 intensity to the S4 intensity falling below a first threshold value lower than a baseline value range,   wherein detecting the WHF event is based at least in part on the impaired diastolic function.   
     
     
         16 . The method of  claim 13 , wherein the determined heart sound component includes a ratio of an S3 intensity to an S4 intensity, the method further comprising:
 determining an indicator of restrictive ventricular filling in response to the determined ratio of the S3 intensity to the S4 intensity exceeding a second threshold value greater than a baseline value range; and   detecting the WHF event based at least in part on the restrictive ventricular filling.   
     
     
         17 . The method of  claim 13 , wherein the determined heart sound component includes a cardiac timing parameter including at least one of:
 a pre-ejection period;   a systolic timing interval;   a left-ventricular ejection time; or   a diastolic timing interval.   
     
     
         18 . The method of  claim 12 , comprising determining one or more VM phases using the sensed heart sound signal,
 wherein generating the diastolic function indictor includes using the sensed heart sound signal during at least one of the determined one or more VM phases.   
     
     
         19 . The method of  claim 18 , wherein determining the one or more VM phases is based at least in part on an increase or decrease trend of one or more of an S1 intensity, an S2 intensity, an S3 intensity, or an S4 intensity. 
     
     
         20 . The method of  claim 12 , further comprising initiating or adjusting a therapy to the patient in response to the detection of the WHF event.