Estimating acute response to cardiac resynchronization therapy

• US 20080243202A1
• Filed: 03/29/2007
• Published: 10/02/2008
• Est. Priority Date: 03/29/2007
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Krishnan, Mohan, Patangay, Abhilash, Carlson, Gerrard M., Siejko, Krzysztof
• Granted Patent: US 8,229,557 B2
• Time in Patent Office: Days
• US Class Current: 607/27
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• 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 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/1102 Ballistocardiography
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/7267 involving training the classification device
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• 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 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control

Abstract

Systolic timing intervals are measured in response to delivering pacing energy to a pacing site of a patient'"'"'s heart. An estimate of a patient'"'"'s acute response to cardiac resynchronization therapy (CRT) for the pacing site is determined using the measured systolic timing intervals. The estimate is compared to a threshold. The threshold preferably distinguishes between acute responsiveness and non-responsiveness to CRT for a patient population. An indication of acute responsiveness to CRT for the pacing site may be produced in response to the comparison.

Claims

1. A method, comprising:

measuring systolic timing intervals based on cardiac events for a patient'"'"'s heart;

computing an estimate of acute responsiveness to cardiac resynchronization therapy (CRT) for a pacing site of the patient'"'"'s heart using the measured systolic timing intervals;

comparing the estimate to a threshold, the threshold distinguishing between acute responsiveness and non-responsiveness to CRT for a patient population; and

producing an indication of acute responsiveness to CRT for the pacing site in response to the comparison.

2. The method of claim 1, wherein producing the indication of acute responsiveness to CRT comprises producing a binary indication of acute responsiveness to CRT for the pacing site.

3. The method of claim 1, wherein producing the indication of acute responsiveness to CRT further comprises producing a confidence indication indicative of relative acute responsiveness to CRT for the pacing site.

4. The method of claim 3, further comprising setting an atrio-ventricular delay for the CRT based on a positive indication of acute responsiveness to CRT and the confidence indication.

5. The method of claim 1, wherein producing the indication of acute responsiveness to CRT comprises one or both of:

producing a binary indication of acute responsiveness to CRT for the pacing site; and

producing a confidence indication indicative of relative acute responsiveness to CRT for the pacing site;

the method further comprising generating a human perceivable indication of one or both of the binary indication of acute responsiveness to CRT and the confidence indication.

6. The method of claim 1, further comprising implanting an electrode of an implantable cardiac lead at the pacing site in response to a positive indication of acute responsiveness to CRT for the pacing site.

7. The method of claim 1, wherein the systolic timing intervals are measured in response to pacing the pacing site using one or more atrio-ventricular delay values.

8. The method of claim 1, wherein the systolic timing intervals are associated with mechanical activity of the patient'"'"'s heart.

9. The method of claim 1, wherein the systolic timing intervals are measured using features of signals associated with mechanical and electrical activity of the patient'"'"'s heart.

10. The method of claim 1, wherein measuring the systolic timing intervals comprises measuring timing intervals associated with one or both of heart sounds and arterial blood pressure.

11. The method of claim 1, wherein measuring the systolic timing intervals comprises measuring timing intervals associated with cardiac stroke impedance.

12. The method of claim 1, wherein a positive indication of acute responsiveness indicates that the pacing site is electrically suitable for CRT and provides for improved patient hemodynamics.

13. The method of claim 1, wherein the systolic timing intervals are measured in response to delivering pacing energy to the pacing site using a plurality of atrio-ventricular delay values.

14. The method of claim 1, wherein the systolic timing intervals are measured for paced beats associated with the pacing site.

15. The method of claim 1, wherein the systolic timing intervals are measured for unpaced beats associated with the pacing site.

16. A medical system, comprising:

an electrode for delivering pacing pulses to a patient'"'"'s heart;

an energy delivery and sensing unit coupled to the electrode;

a hemodynamic sensor;

a memory configured to store at least a threshold that distinguishes between acute responsiveness and non-responsiveness to CRT for a patient population; and

a controller coupled to the memory, hemodynamic sensor, and the energy delivery and sensing unit, the controller configured to measure systolic timing intervals derived from signals produced by the hemodynamic sensor in response to pacing pulses delivered to a pacing site of a patient'"'"'s heart, and to compute an estimate of acute responsiveness to cardiac resynchronization therapy (CRT) for the pacing site using the measured systolic timing intervals and the threshold.

17. The medical system of claim 16, wherein the controller is configured to implement a fusion algorithm for computing the estimate of acute responsiveness to CRT for the pacing site.

18. The medical system of claim 16, wherein the controller is configured to compare the estimate to the threshold and produce an indication of acute responsiveness to CRT for the pacing site in response to the comparison.

19. The medical system of claim 16, wherein the hemodynamic sensor comprises a sensor configured to sense mechanical activity of the patient'"'"'s heart.

20. The medical system of claim 16, wherein the hemodynamic sensor comprises a sensor configured to sense mechanical activity of the patient'"'"'s heart and a sensor configured to sense electrical activity of the patient'"'"'s heart, the controller measuring the systolic timing intervals derived from features of signals produced by the mechanical and electrical activity sensors.

21. The medical system of claim 16, wherein the hemodynamic sensor comprises a cardiac stroke impedance sensor.

22. The medical system of claim 16, wherein the hemodynamic sensor comprises a heart sounds sensor.

23. The medical system of claim 16, wherein the hemodynamic sensor comprises a cardiac stroke impedance sensor and a heart sounds sensor, the controller measuring the systolic timing intervals derived from features of signals produced by the cardiac stroke impedance sensor and the heart sounds sensor.

24. The medical system of claim 16, wherein the system is configured for implantation in a patient.

25. The medical system of claim 16, wherein at least a portion of the system is configured for implantation in a patient and another portion of the system is configured for operation external to the patient.

26. The medical system of claim 16, wherein the systolic timing intervals include systolic timing intervals measured for unpaced beats associated with the pacing site.

27. A medical system, comprising:

means for measuring systolic timing intervals in response to cardiac events for a patient'"'"'s heart;

means for computing an estimate of acute responsiveness to cardiac resynchronization therapy (CRT) for a pacing site of the patient'"'"'s heart using the measured systolic timing intervals;

means for comparing the estimate to a threshold, the threshold distinguishing between acute responsiveness and non-responsiveness to CRT for a patient population; and

means for producing an indication of acute responsiveness to CRT for the pacing site in response to the comparison.