SYSTEM AND METHOD OF DETERMINING ARTERIAL BLOOD PRESSURE AND VENTRICULAR FILL PARAMETERS FROM VENTRICULAR BLOOD PRESSURE WAVEFORM DATA

• US 20090275843A1
• Filed: 04/30/2008
• Published: 11/05/2009
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: KARAMANOGLU, MUSTAFA, Bennett, Tommy D.
• Granted Patent: US 8,211,028 B2
• Time in Patent Office: Days
• US Class Current: 600/486
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/36564 controlled by blood pressure

Abstract

A system and method of determining hemodynamic parameters uses sensed ventricular blood pressure during a portion of ventricular pressure waveform following peak pressure. An estimated arterial diastolic pressure is based upon an amplitude of the sensed ventricular pressure corresponding to a time at which a first derivative of ventricular pressure as a function of time is at a minimum (dP/dt_min). Fill parameters such as isovolumetric relaxation constant, ventricular suction pressure, atrial kick pressure, and transvalve pressure gradient are derived from measured pressures representing minimum ventricular pressure, ventricular diastolic pressure, and diastasis pressure.

Claims

1. An implantable medical device, comprising:

an input circuit that receives a pressure waveform signal representative of a pressure (P) sensed within a ventricle of a patient'"'"'s heart as a function of time (t); and

a processor that derives from the pressure waveform signal at least one hemodynamic parameter based upon at least one ventricular pressure value during a portion of the pressure waveform signal between a peak ventricular pressure and a beginning of a next ventricular pumping cycle.

2. An implantable medical device according to claim 1, wherein the processor derives an estimated arterial diastolic pressure based upon pressure in the ventricle at a time corresponding to a maximum rate of pressure decline (dP/dt_min).

3. An implantable medical device according to claim 1 and further comprising a blood pressure sensor located in the ventricle for providing the pressure waveform signal to the input circuit.

4. An implantable medical device according to claim 3, wherein the blood pressure sensor is a right ventricular pressure sensor, and the estimated arterial diastolic pressure is an estimated pulmonary artery diastolic pressure.

5. An implantable medical device according to claim 3, wherein the blood pressure sensor is a left ventricular pressure sensor, and the estimated arterial diastolic pressure is an estimated aortic diastolic pressure.

6. An implantable medical device according to claim 1, wherein the input circuit also receives an electrical signal representative of electrical activity in the heart as a function of time.

7. An implantable medical device according to claim 1, wherein the processor derives from the pressure waveform signal at least one ventricular fill parameter based upon pressure values during a fill portion between occurrence of dP/dt_min and the beginning of a next ventricular pumping cycle.

8. An implantable medical device according to claim 7, wherein the processor derives at least one ventricular fill parameter by:

producing a dP/dt waveform from the pressure signal;

identifying a fill portion of the pressure waveform signal;

identifying a diastasis portion of the fill portion using the dP/dt waveform; and

deriving a diastasis pressure representing the ventricular pressure in the diastasis portion of the pressure waveform signal.

9. An implantable medical device according to claim 7, wherein the processor determines from the fill portion of the pressure waveform signal a ventricular diastolic pressure, a minimum ventricular pressure, and a diastasis pressure.

10. An implantable medical device according to claim 9 wherein the processor derives ah atrial kick parameter based upon a difference between the ventricular end diastolic pressure and the diastasis pressure.

11. An implantable medical device according to claim 9, wherein the processor derives a ventricular suction parameter based upon a difference between the diastasis ventricular pressure and the minimum ventricular pressure.

12. An implantable medical device according to claim 9, wherein the processor derives a transvalve pressure gradient parameter based upon a difference between the ventricular diastolic pressure and the minimum ventricular pressure.

13. An implantable medical device according to claim 1, wherein the process derives an isovolumetric relaxation constant based upon dP/dt_min, a ventricular pressure at dP/dt_min (P_STI), and a ventricular pressure at occurrence of an R-wave (VDP).

14. A method, comprising:

sensing ventricular blood pressure to produce a ventricular pressure waveform; and

deriving at least one hemodynamic parameter based upon at least one ventricular pressure during a portion of the ventricular pressure waveform between a peak ventricular pressure and a beginning of a next ventricular pumping cycle.

15. A method according to claim 14, wherein deriving at least one hemodynamic parameter comprises:

deriving an estimated arterial diastolic pressure based upon ventricular pressure amplitude at a time when dP/dt_min occurs.

16. A method according to claim 15, wherein the ventricular blood pressure is sensed by a blood pressure sensor located in a ventricle.

17. A method according to claim 16, wherein one of:

the ventricle comprises a right ventricle, and the estimated arterial diastolic pressure is an estimated pulmonary artery diastolic pressure, and

the ventricle is a left ventricle and the estimated arterial diastolic pressure comprises an estimated aortic diastolic pressure.

18. An implantable medical device, comprising:

an input circuit that receives a pressure waveform signal representative of a pressure (LVP) sensed within a left ventricle of a patient'"'"'s heart as a function of time (t); and

a processor that derives from the pressure waveform signal at least one hemodynamic parameter based upon at least one left ventricular pressure value.

19. An implantable medical device according to claim 18, further comprising a blood pressure sensor located in the left ventricle for providing the pressure waveform signal to the input circuit.

20. An implantable medical device according to claim 18, wherein the processor derives an estimated aortic diastolic pressure based upon at least one of (a) pressure in the left ventricle at a time corresponding to a maximum rate of pressure increase (dP/dt_max), and (b) pressure in the left ventricle at a time corresponding to a maximum rate of pressure decline (dP/dt_min).

21. A method, comprising:

sensing left ventricular blood pressure to produce a left ventricular pressure waveform; and

deriving at least one hemodynamic parameter based upon at least one left ventricular pressure during a left ventricular pressure waveform.

22. A method according to claim 21, wherein the left ventricular blood pressure is sensed by a blood pressure sensor located in a left ventricle.

23. A method according to claim 21, wherein deriving at least one hemodynamic parameter comprises:

deriving an estimated aortic diastolic pressure based upon left ventricular pressure amplitude at a time when (a) dP/dt_min occurs, or (b) dP/dt_max occurs.

24. A method according to claim 23, further comprising:

deriving an estimated aortic systolic pressure based upon a maximum sensed left ventricular blood pressure.

25. A method according to claim 24, further comprising:

deriving an estimated aortic mean pressure based upon the estimated aortic systolic pressure and the estimated aortic diastolic pressure.