System and method for monitoring a ventricular pressure index to predict worsening heart failure

• US 20060167516A1
• Filed: 01/27/2005
• Published: 07/27/2006
• Est. Priority Date: 01/27/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Bennett, Tommy D., Kjellstrom, Barbro M.
• Granted Patent: US 8,594,790 B2
• Time in Patent Office: Days
• US Class Current: 607/23
• CPC Class Codes: A61N 1/36564 controlled by blood pressure

Abstract

A medical device monitors a patient to predict worsening heart failure. An input circuit of the medical device receives a pressure signal representative of a pressure sensed within a ventricle of the patient'"'"'s heart as a function of time. A processor derives from the pressure signal a ventricular pressure index for a ventricular contraction based upon pressures in the ventricle. The processor then provides an output based upon the ventricular pressure index.

Claims

1. A medical device for monitoring heart failure in a patient, the medical device comprising:

an input circuit that receives a pressure signal representative of a pressure sensed within a ventricle as a function of time; and

a processor that derives from the pressure signal a ventricular pressure index for a ventricular contraction based upon pressures in the ventricle and provides an output based upon the ventricular pressure index.

2. The medical device of claim 1 and further comprising a blood pressure sensor located in the ventricle for providing the pressure signal to the input circuit.

3. The medical device of claim 2 wherein the blood pressure sensor is located in the right ventricle.

4. The medical device of claim 1 wherein the input circuit also receives an electrical signal representative of electrical activity in the heart as a function of time.

5. The medical device of claim 4 wherein, for the ventricular contraction, the processor determines from the electrical signal and the pressure signal a diastolic pressure in the ventricle and a systolic pressure in the ventricle and estimates from the electrical signal and the pressure signal a diastolic pressure in a vessel into which the ventricle pumps blood.

6. The medical device of claim 5 wherein the processor determines the ventricular pressure index for a ventricular contraction as a function of the systolic pressure in the ventricle, the diastolic pressure in the ventricle, and the diastolic pressure in the blood vessel.

7. The medical device of claim 1 and further comprising memory for storing a ventricular pressure index threshold determined for the patient during an initialization period, wherein the processor detects when the ventricular pressure index has fallen below the ventricular pressure index threshold.

8. The medical device of claim 7 wherein the output provided by the processor is a warning signal indicating that the ventricular pressure index has fallen below the ventricular pressure index threshold.

9. The medical device of claim 1 wherein the output provided by the processor is a therapy control signal based upon the ventricular pressure index, the control signal being provided to adjust a therapy of the patient.

10. The medical device of claim 1 wherein the output is a waveform representing the ventricular pressure index as a function of time.

20. The method of claim 1 wherein providing an output based upon the ventricular pressure index comprises:

outputting a waveform representing the ventricular pressure index as a function of time.

11. A method for predicting worsening heart failure in a patient, the method comprising:

sensing a blood pressure within a ventricle of the patient'"'"'s heart as a function of time;

deriving from the sensed blood pressures a ventricular pressure index for a ventricular contraction based upon blood pressures in the ventricle; and

providing an output based upon the ventricular pressure index.

12. The method of claim 11 wherein the blood pressure is sensed by a blood pressure sensor located in a ventricle of the heart.

13. The method of claim 12 wherein the ventricle is a right ventricle.

14. The method of claim 11 and further comprising:

obtaining an electrical signal representative of electrical activity in the heart as a function of time.

15. The method of claim 14 wherein deriving a ventricular pressure index for a ventricular contraction further comprises:

determining from the sensed blood pressures for the ventricular contraction, a diastolic pressure in the ventricle and a systolic pressure in the ventricle; and

estimating from the sensed blood pressures for the ventricular contraction, a diastolic pressure in the blood vessel into which the ventricle pumps blood.

16. The method of claim 15 wherein determining a ventricular pressure index for a ventricular contraction comprises:

determining the ventricular pressure index as a function of the systolic pressure in the ventricle, the diastolic pressure in the ventricle, and the diastolic pressure in the blood vessel.

17. The method of claim 11 and further comprising:

determining a ventricular pressure index threshold for the patient during an initialization period; and

detecting when the ventricular pressure index has fallen below the ventricular pressure index threshold.

18. The method of claim 17 wherein providing an output based upon the ventricular pressure index comprises:

providing an warning upon the detection of the ventricular pressure index falling below the ventricular pressure index threshold.

19. The method of claim 11 wherein providing an output based upon the ventricular pressure index comprises:

providing a therapy control signal based upon the ventricular pressure index, the control signal being provided to adjust a therapy of the patient.

21. A method for determining a set of pacing settings for a pacemaker implanted in a patient, the method comprising:

administering a plurality of pacing settings, each pacing setting being administered for a period of time;

monitoring an effect of each pacing setting on a ventricular pressure index, the ventricular pressure index being determined from a pressure signal sensed from within a ventricle of the patient'"'"'s heart; and

selecting from the plurality of pacing settings a set of pacing settings based upon the ventricular pressure index.