System and method for evaluating cardiac performance relative to performance of an intrathoracic pressure maneuver

Abstract

A system and method for evaluating cardiac performance relative to performance of an intrathoracic pressure maneuver is described. Blood pressure is indirectly sensed by directly collecting intracardiac impedance measures through an implantable medical device. Cardiac functional changes to the blood pressure are evaluated in response to performance of an intrathoracic pressure maneuver.

1 . A system for evaluating cardiac performance relative to performance of an intrathoracic pressure maneuver, comprising:
 an implantable medical device to indirectly sense blood pressure by directly collecting intracardiac impedance measures; and   an analysis component to evaluate cardiac functional changes to the blood pressure in response to performance of an intrathoracic pressure maneuver.   
   
   
       2 . A system according to  claim 1 , wherein the blood pressure comprises at least one of arterial pressure, cardiac chamber pressure, systolic pressure, and diastolic pressure. 
   
   
       3 . A system according to  claim 2 , wherein the cardiac chamber pressure comprises left ventricular end diastolic pressure. 
   
   
       4 . A system according to  claim 1 , wherein the implantable medical device comprises at least one of a bradycardia, tachycardia, heart failure, therapy delivery, and monitoring device. 
   
   
       5 . A system according to  claim 1 , further comprising:
 at least one lead to couple to the implantable medical device and to sense at least one of the intracardiac impedance measures across the thoracic cavity and the intracardiac impedance measures across the heart.   
   
   
       6 . A system according to  claim 1 , wherein the intrathoracic pressure maneuver comprises at least one of a Valsalva and Müller maneuver. 
   
   
       7 . A system according to  claim 1 , further comprising:
 an evaluation subcomponent to evaluate at least one of overdamping and underdamping cardiac impedance response relative to normative levels.   
   
   
       8 . A system according to  claim 7 , further comprising:
 a notification subcomponent to generate a notification responsive to the at least one of overdamping and underdamping cardiac impedance response.   
   
   
       9 . A system according to  claim 1 , wherein thoracic pressure is monitored during the intrathoracic pressure maneuver. 
   
   
       10 . A system according to  claim 9 , further comprising:
 an external pressure monitor to define a confined volume configured to receive a forced exhalation and to measure the thoracic pressure relative to the confined volume.   
   
   
       11 . A system according to  claim 9 , further comprising:
 a thoracic pressure sensor to internally measure thoracic pressure.   
   
   
       12 . A method for evaluating cardiac performance relative to performance of an intrathoracic pressure maneuver, comprising:
 indirectly sensing blood pressure by directly collecting intracardiac impedance measures through an implantable medical device; and   evaluating cardiac functional changes to the blood pressure in response to performance of an intrathoracic pressure maneuver.   
   
   
       13 . A method according to  claim 12 , wherein the blood pressure comprises at least one of arterial pressure, cardiac chamber pressure, systolic pressure, and diastolic pressure. 
   
   
       14 . A method according to  claim 13 , wherein the cardiac chamber pressure comprises left ventricular end diastolic pressure. 
   
   
       15 . A method according to  claim 12 , wherein the implantable medical device comprises at least one of a bradycardia, tachycardia, heart failure, therapy delivery, and monitoring device. 
   
   
       16 . A method according to  claim 12 , further comprising:
 sensing at least one of the intracardiac impedance measures across the thoracic cavity and the intracardiac impedance measures across the heart.   
   
   
       17 . A method according to  claim 12 , wherein the intrathoracic pressure maneuver comprises at least one of a Valsalva and Müller maneuver. 
   
   
       18 . A method according to  claim 12 , further comprising:
 evaluating at least one of overdamping and underdamping cardiac impedance response relative to normative levels.   
   
   
       19 . A method according to  claim 18 , further comprising:
 generating a notification responsive to the at least one of overdamping and underdamping cardiac impedance response.   
   
   
       20 . A method according to  claim 12 , further comprising:
 monitoring thoracic pressure during the intrathoracic pressure maneuver.   
   
   
       21 . A method according to  claim 20 , further comprising:
 defining a confined volume configured to receive a forced exhalation; and   measuring the thoracic pressure relative to the confined volume.   
   
   
       22 . A method according to  claim 20 , further comprising:
 internally measuring thoracic pressure.   
   
   
       23 . An apparatus for evaluating cardiac performance relative to performance of an intrathoracic pressure maneuver, comprising:
 means for indirectly sensing blood pressure by directly collecting intracardiac impedance measures through an implantable medical device; and   means for evaluating cardiac functional changes to the blood pressure in response to performance of an intrathoracic pressure maneuver.