MECHANICAL FUNCTION MARKER CHANNEL FOR CARDIAC MONITORING AND THERAPY CONTROL

• US 20090024045A1
• Filed: 07/19/2007
• Published: 01/22/2009
• Est. Priority Date: 07/19/2007
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Prakash, Rajan, Sowelam, Sameh, Mullen, Thomas J.
• Granted Patent: US 8,340,750 B2
• Time in Patent Office: Days
• US Class Current: 600/523
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: A61N 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone

Abstract

The implantable medical device (IMD) system disclosed here utilizes one or more cardiac sensors that measure mechanical characteristics of the heart, such as left ventricular acceleration or right ventricular pressure. The raw sensor data is collected and processed by the IMD, which derives one or more mechanical event marker signals from features, traits, and characteristics of the sensor data waveforms. The mechanical event marker signals are wirelessly transmitted to an external monitor device for display.

Claims

1. A method of obtaining information related to a cardiac cycle comprising:

receiving a physiological data signal from a mechanical characteristic sensor, where the physiological data signal is indicative of a mechanical cardiac function;

deriving cardiac event markers from attributes of the physiological data signal; and

generating a cardiac event marker signal using the cardiac event markers, the cardiac event marker signal identifying cardiac cycle timing characteristics.

2. The method of claim 1, further comprising transmitting the cardiac event marker signal to a device external to the IMD.

3. The method of claim 1, wherein receiving a physiological data signal comprises receiving a heart wall acceleration signal from an accelerometer configured to measure acceleration of a heart wall.

4. The method of claim 3, wherein receiving the heart wall acceleration signal comprises receiving a left ventricular acceleration signal from the accelerometer.

5. The method of claim 4, wherein deriving cardiac event markers comprises deriving an atrial mechanical contraction event marker from the left ventricular acceleration signal.

6. The method of claim 4, wherein deriving cardiac event markers comprises deriving an aortic valve opening event marker from the left ventricular acceleration signal.

7. The method of claim 4, wherein deriving cardiac event markers comprises deriving an aortic valve closing event marker from the left ventricular acceleration signal.

8. The method of claim 4, wherein deriving cardiac event markers comprises deriving a left ventricular mechanical contraction event marker from the left ventricular acceleration signal.

9. The method of claim 4, wherein deriving cardiac event markers comprises deriving a mitral valve opening event marker from the left ventricular acceleration signal.

10. The method of claim 4, wherein deriving cardiac event markers comprises deriving a mitral valve closing event marker from the left ventricular acceleration signal.

11. The method of claim 1, wherein receiving a physiological data signal comprises receiving a heart chamber pressure signal from a pressure sensor configured to measure pressure within a heart chamber.

12. The method of claim 11, wherein receiving the heart chamber pressure signal comprises receiving a right ventricle pressure signal from the pressure sensor.

13. The method of claim 12, wherein deriving cardiac event markers comprises deriving a pre-ejection interval event marker from the right ventricle pressure signal.

14. The method of claim 12, wherein deriving cardiac event markers comprises deriving a systolic time interval event marker from the right ventricle pressure signal.

15. The method of claim 12, wherein deriving cardiac event markers comprises deriving an ejection time interval event marker from the right ventricle pressure signal.

16. The method of claim 12, wherein deriving cardiac event markers comprises deriving an estimated pulmonary artery diastolic pressure event marker from the right ventricle pressure signal.

17. The method of claim 12, wherein deriving cardiac event markers comprises:

generating a secondary signal based upon a first derivative of the right ventricle pressure signal; and

deriving the cardiac event markers from attributes of the secondary signal.

18. The method of claim 1, further comprising receiving at least one additional physiological data signal from a physiological characteristic sensor, where the at least one additional physiological data signal is indicative of cardiac functionality, and where deriving cardiac event markers comprises deriving cardiac event markers from attributes of the physiological data signal and from attributes of the at least one additional physiological data signal.

19. An implantable medical device (IMD) comprising:

a data collection module configured to obtain a physiological data signal indicative of mechanical cardiac functionality;

a data processing module coupled to the data collection module, the data processing module being configured to derive cardiac event markers from attributes of the physiological data signal, and to generate a cardiac event marker signal using the cardiac event markers, the cardiac event marker signal identifying cardiac cycle timing characteristics; and

a communication module coupled to the data processing module, the communication module being configured to transmit the cardiac event marker signal to a device external to the IMD.

20. The IMD of claim 19, further comprising an accelerometer coupled to the data collection module, the accelerometer being configured to measure acceleration of a heart wall, and to provide the physiological data signal as a heart wall acceleration signal.

21. The IMD of claim 19, further comprising a pressure sensor coupled to the data collection module, the pressure sensor being configured to measure pressure within a heart chamber, and to provide the physiological data signal as a heart chamber pressure signal.

22. An implantable medical device (IMD) system comprising:

a data collection module configured to obtain a physiological data signal indicative of mechanical cardiac functionality;

a data processing module coupled to the data collection module, the data processing module being configured to derive cardiac event markers from attributes of the physiological data signal, and to generate a cardiac event marker signal using the cardiac event markers, the cardiac event marker signal identifying cardiac cycle timing characteristics; and

a communication module coupled to the data processing module, the communication module being configured to transmit the cardiac event marker signal to devices external to the IMD;

a mechanical characteristic sensor in communication with the IMD and configured to generate the physiological data signal in response to mechanical cardiac phenomena; and

a monitor device in communication with the IMD, the monitor device being configured to receive the cardiac event marker signal from the communication module, and to display a graphical representation of the cardiac event marker signal.

23. The IMD system of claim 22, wherein the mechanical characteristic sensor comprises an accelerometer coupled to the data collection module, the accelerometer being configured to measure acceleration of a heart wall, and to provide the physiological data signal as a heart wall acceleration signal.

24. The IMD system of claim 22, wherein the mechanical characteristic sensor comprises a pressure sensor coupled to the data collection module, the pressure sensor being configured to measure pressure within a heart chamber of the patient, and to provide the physiological data signal as a heart chamber pressure signal.

25. The IMD system of claim 22, the monitor device being configured to acquire an electrogram signal, and to display a graphical representation of the electrogram signal concurrently with the graphical representation of the cardiac event marker signal.

26. The IMD system of claim 25, the data collection module being configured to obtain the electrogram signal from electrodes coupled to the IMD, and the data processing module being configured to derive the cardiac event markers from attributes of the physiological data signal and attributes of the electrogram signal.

27. The IMD system of claim 22, the monitor device being configured to acquire an electrocardiogram signal for the patient, and to display a graphical representation of the electrocardiogram signal concurrently with the graphical representation of the cardiac event marker signal.

28. A method for obtaining information related to a cardiac cycle, the method comprising:

obtaining a cardiac mechanical function marker signal that identifies mechanical events associated with the cardiac cycle; and

displaying a graphical representation of the cardiac mechanical function marker signal.

29. The method of claim 28, wherein displaying a graphical representation of the cardiac mechanical function marker signal comprises displaying an event marker indicative of mechanical events selected from the group consisting of:

an atrial mechanical contraction event;

an aortic valve opening event;

an aortic valve closing event;

a left ventricular mechanical contraction event;

a mitral valve opening event;

a mitral valve closing event;

a pre-ejection interval event;

a systolic time interval event;

an ejection time interval event; and

an estimated pulmonary artery diastolic pressure event.