Method and apparatus for sensing improvement using pressure data

• US 7,890,162 B2
• Filed: 04/30/2007
• Issued: 02/15/2011
• Est. Priority Date: 04/30/2007
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gordon, Charles R., Davie, Scott W., Whitman, Teresa A., Kleckner, Karen J., Cho, Yong K., Brown, Mark L.
• Primary Examiner(s): Patel; Niketa I
• Assistant Examiner(s): El-Kaissi; Hiba
• Application Number:
  US11/741,942
• Publication Number:
  US 20080269627A1
• Time in Patent Office: 1,387 Days
• Field of Search: 607/6, 607/9, 607/14, 607/17, 607/18, 607/23, 607/24, 600/521
• US Class Current: 600/521
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3962 in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

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.

Claims

1. A method of confirming that an EGM deflection represents an R-wave comprising:

sensing an EGM via an implantable medical device (IMD);

sensing an intracardiac pressure via the IMD;

determining a dP/dt of the sensed intracardiac pressure;

detecting an electrical event using the EGM;

opening a time window after detecting the electrical event;

determining a maximum positive dP/dt of the intracardiac pressure sensed during the open time window;

detecting the presence of a mechanical event responsive to the maximum positive dP/dt being greater than a first threshold; and

determining that the electrical event includes an R-wave responsive to the presence of the mechanical event;

determining a minimum negative dP/dt of the intracardiac pressure sensed during the open time window; and

detecting the presence of an oversensed T-wave or noise using the minimum negative dP/dt, the oversensed T-wave or noise being deemed present when the mechanical event is deemed absent and an absolute value of the minimum negative dP/dt is greater than a second threshold.

2. A method according to claim 1, further comprising withholding defibrillation when the EGM indicates a tachyarrhythmia and the oversensed T-wave or noise is deemed present.

3. A method according to claim 1, further comprising detecting the presence of an R-wave with no corresponding mechanical event, the R-wave without a corresponding mechanical event being deemed present when the mechanical event is deemed absent and an absolute value of the minimum dP/dt is not greater than a second threshold.

4. A method according to claim 1, further comprising recording the presence of the mechanical event by the device on a marker channel.

5. A method according to claim 1, wherein the first threshold is approximately 100 mmHg/s.

6. A method according to claim 1, wherein the time window is between approximately 400 and approximately 500 milliseconds or equal to the duration between two sequentially detected R-waves, which ever is smallest.