Method and apparatus for sensing improvement using pressure data

Abstract

A method and apparatus for sensing improvement using pressure data. The method and apparatus may be used in an implantable medical device to confirm that an EGM event signifies a true mechanical cardiac activity and not just electrical oversensing. The mechanical activity may be used to create a mechanical marker channel in the implantable medical device.

1 . A method of confirming that an implantable medical device (IMD) is not oversensing electrical activity in an EGM, comprising:
 sensing an EGM via an implantable medical device;   detecting electrical events using the EGM;   sensing an intracardiac pressure via the IMD;   determining a dP/dt of the sensed intracardiac pressure;   detecting the presence of a mechanical event using the dP/dt, a mechanical event being deemed present when the dP/dt exceeds a threshold, the electrical events and mechanical events being detected independently from each other; and   comparing the electrical events to the mechanical events to identify which electrical events are followed by and associated with mechanical events, the identification of associated electrical and mechanical events indicating that such electrical events have not been oversensed.   
     
     
         2 . A method according to  claim 1 , wherein mechanical events occurring between a first electrical event and a subsequent electrical event are deemed to be associated with the first electrical event. 
     
     
         3 . A method according to  claim 1 , wherein the intracardiac pressure and the EGM are right ventricular and wherein the electrical events followed by and associated with mechanical events include an R-wave. 
     
     
         4 . A method according to  claim 3 , further including identifying which electrical events are not followed by or associated with mechanical events, such electrical events indicating T-wave oversensing or noise. 
     
     
         5 . A method according to  claim 1 , further comprising withholding defibrillation when the EMG indicates a tachyarrhythmia but the oversensed T-waves or noise is indicated. 
     
     
         6 . A method according to  claim 1 , wherein the intracardiac pressure and the EGM are right atrial. 
     
     
         7 . A method according to  claim 6 , wherein the electrical events not followed by and associated with mechanical events indicate far field R wave oversensing. 
     
     
         8 . A computer-readable medium programmed with instructions for operating an implantable medical device, the medium comprising instructions for causing a programmable processor to:
 receive sensed intracardiac pressure;   identify mechanical events using the sensed intracardiac pressure; and   store the mechanical events as a mechanical sense channel.   
     
     
         9 . A computer-readable medium of  claim 8 , further comprising instructions to ignore mechanical events occurring within a threshold time period after another mechanical event. 
     
     
         10 . A computer-readable medium of  claim 8 , further comprising instructions to provide cardiac stimulation when mechanical events occur within a threshold time period after another mechanical event, the mechanical events indicating an arrhythmia. 
     
     
         20 . A computer-readable medium of  claim 8 , further comprising instructions to determine a dP/dt of the sensed intracardiac pressure, the mechanical events being identified based on the dP/dt.