System and method for detecting heart failure and pulmonary edema based on ventricular end-diastolic pressure using an implantable medical device

• US 20060224190A1
• Filed: 04/05/2005
• Published: 10/05/2006
• Est. Priority Date: 04/05/2005
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Gill, Jong, Min, Xiaoyi
• Granted Patent: US 7,437,192 B2
• Time in Patent Office: Days
• US Class Current: 607/3
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36564 controlled by blood pressure

Abstract

Techniques are provided for detecting left ventricular end diastolic pressure (LV EDP) using a pressure sensor implanted within the heart of a patient and for detecting and evaluating heart failure and pulmonary edema based on LV EDP. Briefly, the peak of the R-wave of an intracardiac electrogram (IEGM) is used to trigger the measurement of a pressure value within the left ventricle. This pressure value is deemed to be representative of LV EDP. In this manner, LV EDP is easily detected merely by measuring pressure at one point within the heartbeat—thereby eliminating any need to track ventricular pressure throughout the heartbeat. Techniques for detecting and evaluating heart failure and pulmonary edema based on the R-wave triggered LV EDP measurements are also set forth herein.

Claims

1. A method for detecting ventricular end diastolic pressure (EDP) within a patient having an implantable medical device equipped with at least one electrical cardiac sensing lead and a pressure sensor, the method comprising:

detecting a peak amplitude within an electrical cardiac signal sensed during a heartbeat using the lead; and

detecting a value representative of ventricular EDP for the heartbeat using the pressure sensor by measuring pressure at a time substantially contemporaneous with the peak the electrical cardiac signal.

2. The method of claim 1 wherein the peak amplitude detected during the heartbeat is the peak of an R-wave portion of a QRS-complex of the heartbeat.

3. The method of claim 1 wherein the pressure is measured at a time within a detection window surrounding the peak of the electrical cardiac signal, the window extending throughout the end diastolic phase of the heartbeat.

4. The method of claim 1 further comprising tracking changes in ventricular EDP over time.

5. The method of claim 4 wherein tracking changes in ventricular EDP over time comprises tracking ventricular EDP over a plurality of heartbeats.

6. The method of claim 4 wherein tracking changes in ventricular EDP over time further comprises:

tracking respiration cycles;

tracking heart beats;

averaging ventricular EDP over heart beats during one respiration cycle;

identifying changes in averaged ventricular EDP due to respiration;

and

detecting changes, if any, in averaged ventricular EDP not due to respiration.

7. The method of claim 4 further comprising detecting the onset of a selected medical condition within the patient based on changes in ventricular EDP over time.

8. The method of claim 7 wherein the medical condition is any condition associated with a detectable change in ventricular EDP over time.

9. The method of claim 7 wherein detecting the onset of a selected medical condition is performed by determining whether an increase in LV EDP exceeds a heart failure detection threshold.

10. The method of claim 7 wherein detecting the onset of a selected medical condition is performed by determining whether an increase in LV EDP exceeds a pulmonary edema detection threshold.

11. The method of claim 7 further comprising delivering therapy in response to the medical condition.

12. The method of claim 11 wherein delivering therapy comprises delivering cardiac resynchronization therapy (CRT.)

13. The method of claim 11 wherein the device is equipped with an implantable drug pump and wherein delivering therapy comprises delivering selected medications to the patient using the drug pump.

14. The method of claim 7 further comprising generating a warning signal in response to the medical condition.

15. The method of claim 7 wherein detecting the onset of the medical condition is performed by an external programmer device based on signals received from the implanted device.

16. The method of claim 7 further comprising evaluating the severity of the medical condition based on the values representative of LV EDP.

17. The method of claim 16 further comprising tracking changes, if any, in the severity of the medical condition within the patient based on any changes over time in the values representative of LV EDP.

18. The method of claim 1 wherein detecting a value representative of ventricular EDP comprises measuring one of left atrial pressure or left ventricular pressure.

19. A method for detecting the onset of a medical condition within a patient having an implantable medical device equipped with at least one electrical cardiac sensing lead and a pressure sensor, the method comprising:

detecting peak amplitudes within electrical cardiac signals sensed during each of a plurality of heartbeats using the lead;

detecting a value representative of ventricular end diastolic pressure (EDP) for each of the heartbeats using the pressure sensor by measuring pressure at a time based on the peak of the electrical cardiac signal within the heartbeat;

and

detecting the onset of selected medical conditions within the patient based on changes in ventricular EDP over time.

20. A system for detecting ventricular end diastolic pressure (EDP) within a patient having an implantable medical device equipped with at least one electrical cardiac sensing lead and a pressure sensor, the system comprising:

an R-wave detection unit operative to detect a peak amplitude within an electrical cardiac signal sensed during a heartbeat using the lead; and

an R-wave-triggered detection unit operative to detect a value representative of ventricular EDP for the heartbeat using the pressure sensor by measuring pressure at a time substantially contemporaneous with the peak the electrical cardiac signal.

21. A system for detecting ventricular end diastolic pressure (EDP) within a patient having an implantable medical device equipped with at least one electrical cardiac sensing lead and a pressure sensor, the system comprising:

means for detecting a peak amplitude within an electrical cardiac signal sensed during a heartbeat using the leads; and

means for detecting a value representative of ventricular EDP for the heartbeat using the pressure sensor by measuring pressure at a time within the heartbeat selected based on the peak the electrical cardiac signal.