CARDIAC RESYNCHRONIZATION THERAPY OPTIMIZATION USING MECHANICAL DYSSYNCHRONY AND SHORTENING PARAMETERS FROM REALTIME ELECTRODE MOTION TRACKING

• US 20090318995A1
• Filed: 06/01/2009
• Published: 12/24/2009
• Est. Priority Date: 06/20/2008
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Noren, Kjell, Rosenberg, Stuart, Yang, Michael, Hou, Wenbo, Ryu, Kyungmoo, Keel, Allen, Nguyen, Thao Thu
• Granted Patent: US 8,155,739 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• 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 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• 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 1/36514 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 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone
• 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 1/36843 Bi-ventricular stimulation

Abstract

Therapy optimization includes tracking electrode motion using an electroanatomic mapping system and generating, based on tracked electrode motion, one or more mechanical dyssynchrony metrics to thereby guide a clinician in therapy optimization (e.g., via optimal electrode sites, optimal therapy parameters, etc.). Such a method may include a vector analysis of electrode motion with respect to factors such as times in cardiac cycle, phases of a cardiac cycle, and therapy conditions, e.g., pacing sites, pacing parameters and pacing or no pacing. Differences in position-with-respect-to-time data for electrodes may also be used to provide measurements of mechanical dyssynchrony.

Claims

1. A method of characterizing motion of a first electrode implanted along a lateral wall of the left ventricle and a second electrode implanted along a septal wall between the right ventricle and the left ventricle, said method comprising:

for a time in a cardiac cycle, determining a three-dimensional position of the first implanted electrode and a three-dimensional position of the second implanted electrode;

for another time in a cardiac cycle, determining a three-dimensional position of the first implanted electrode and a three-dimensional position of the second implanted electrode;

determining a first vector differential based on a vector for the first implanted electrode for the time in the cardiac cycle and another vector for the first implanted electrode for the other time in the cardiac cycle;

determining a second vector differential based on a vector for the second implanted electrode for the time in the cardiac cycle and another vector for the second implanted electrode for the other time in the cardiac cycle;

processing the first vector differential and the second vector differential to provide a measurement of the motion of one or more of the first implanted electrode and the second implanted electrode.

2. The method of claim 1 wherein processing comprises:

calculating the dot product of the first vector differential and the second vector differential; and

if the dot product is less than zero, determining that the first electrode and the second electrode either move toward each other or away from each other.

3. The method of claim 2 wherein the times in the cardiac cycle comprise times during systole and further comprising repeating the method for times during diastole and deciding whether the dot product is greater than zero for the times during systole and whether the dot product is greater than zero for the times during diastole;

and

if the dot product is greater than zero for the times during systole and for the times during diastole, determining that the motion of the first electrode and the second electrode indicates dyssynchrony of cardiac motion.

4. The method of claim 1 wherein processing comprises:

deciding whether the first vector differential and the second vector differential are approximately zero; and

if the first vector differential and the second vector differential are approximately zero, determining that a condition applied to the heart does not affect cardiac synchrony.

5. The method of claim 4 wherein the condition applied to the heart comprises cardiac resynchronization therapy (CRT).

6. The method of claim 1 wherein processing comprises:

determining the magnitude of the first vector differential and the magnitude of the second vector differential;

summing the magnitudes; and

deciding whether the sum of the magnitudes is greater than a previously determined sum of magnitudes for the first implanted electrode and the second implanted electrode.

7. The method of claim 1 further comprising, for the time in a cardiac cycle, determining, over multiple cardiac cycles, a three-dimensional position of the first implanted electrode and a three-dimensional position of the second implanted electrode wherein the position of the first implanted electrode at the time comprises an average of multiple positions and wherein the position of the second implanted electrode at the time comprises an average of multiple positions.

8. The method of claim 1 further comprising, for the other time in a cardiac cycle, determining, over multiple cardiac cycles, a three-dimensional position of the first implanted electrode and a three-dimensional position of the second implanted electrode wherein the position of the first implanted electrode at the other time comprises an average of multiple positions and wherein the position of the second implanted electrode at the other time comprises an average of multiple positions.

9. The method of claim 1 further comprising performing the method for more than two times in a cardiac cycle.

10. The method of claim 1 wherein processing comprises:

determining a measure of the relative motion between the first electrode and the second electrode based on the of the first vector differential and the second vector differential; and

deciding whether the measure is greater than a previously determined measure.

11. The method of claim 1 further comprising:

performing the method of claim 1 for a plurality of therapy conditions to obtain a corresponding plurality of measurements; and

comparing the plurality of measurements; and

determining an optimal therapy condition based on the comparison.

12. The method of claim 11 wherein the plurality of measurements correspond to relative motion between the electrodes and the optimal therapy condition corresponds to the maximum measurement.

13. The method of claim 11 wherein the plurality of measurements correspond to summations of the absolute values of the first differential vector and the second differential vector and the optimal therapy condition correspond to the maximum measurement.

14. The method of claim 11 wherein the plurality of measurements correspond to the number of times during a common time period that the dot product of the first differential vector and the second differential vector is less than zero and the optimal therapy condition correspond to the maximum measurement.

15. The method of claim 11 wherein therapy conditions comprise one or more of different electrode locations, different pacing parameters and different pacing interventions.

16. A system for characterizing motion of a first electrode implanted along a lateral wall of the left ventricle and a second electrode implanted along a septal wall between the right ventricle and the left ventricle, said system comprising:

one or more processors;

memory; and

control logic, implemented at least in part by the one or more processor and the memory, configured to;

for a time in a cardiac cycle, determine a three-dimensional position of the first implanted electrode and a three-dimensional position of the second implanted electrode;

for another time in a cardiac cycle, determine a three-dimensional position of the first implanted electrode and a three-dimensional position of the second implanted electrode;

determine a first vector differential based on a vector for the first implanted electrode for the time in the cardiac cycle and another vector for the first implanted electrode for the other time in the cardiac cycle;

determine a second vector differential based on a vector for the second implanted electrode for the time in the cardiac cycle and another vector for the second implanted electrode for the other time in the cardiac cycle; and

process the first vector differential and the second vector differential to provide a measurement of the motion of one or more of the first implanted electrode and the second implanted electrode.

17. A method comprising:

providing a feature time corresponding to the appearance of a feature of electrical activity during a cardiac cycle;

providing a time, during the cardiac cycle, corresponding to a peak three-dimensional position of an electrode located along a septal wall between the right ventricle and the left ventricle;

providing a time, during the cardiac cycle, corresponding to a peak three-dimensional position of an electrode located along a lateral wall of the left ventricle;

for the cardiac cycle, with respect to the feature time, determining a septal- to-lateral-wall time delay as a difference between the time of the peak position of the electrode located along the lateral wall and the time of the peak position of the electrode located along the septal wall; and

based on the difference, deciding whether, during the cardiac cycle, cardiac motion was dyssynchronous.

18. The method of claim 17 wherein deciding cardiac motion was dyssynchronous comprises determining that the septal-to-lateral-wall time delay is either greater than a predetermined positive limit or less than a predetermined negative limit.

19. The method of claim 17 further comprising repeating the providings and the determining for multiple cardiac cycles.

20. The method of claim 17 further comprising, if the deciding decides that the cardiac motion was dyssynchronous during the cardiac cycle, calling for delivery of a cardiac pacing therapy.

21. The method of claim 17 wherein the cardiac cycle comprises a paced cardiac cycle associated with a cardiac pacing therapy.

22. The method of claim 21 wherein if the deciding decides that the cardiac motion was dyssynchronous during the cardiac cycle, calling for optimization of the cardiac pacing therapy.

23. The method of claim 22 wherein the optimization optimizes the cardiac pacing therapy by reducing the septal to lateral wall time delay.

24. A method comprising:

for a cardiac cycle, determining a septal-to-lateral-wall time delay as a difference between a time of a peak three-dimensional position of an electrode located along the lateral wall and a time of a peak three-dimensional position of an electrode located along the septal wall;

determining a peak velocity for at least one of the electrodes; and

adjusting a cardiac pacing therapy to minimize the time delay and to maximize the peak velocity.

25. The method of claim 24 further comprising determining a peak velocity for both of the electrodes.

26. The method of claim 25 wherein the adjusting adjusts a cardiac pacing therapy from performing single ventricle pacing to performing biventricular pacing.

27. A method comprising:

providing position-with-respect-to-time data for a plurality of electrodes, at least some of the electrodes located proximate to the right ventricle and at least some of the electrodes located proximate to the left ventricle;

associating various of the electrodes as pairs along longitudes from the apex of the heart to the base of the heart wherein each pair comprises an electrode located proximate to the right ventricle and an electrode located proximate to the left ventricle;

for each pair, determining a longitudinal dyssynchrony metric based on the position-with-respect-to-time data for each electrode in the pair; and

determining a global dyssynchrony metric based on the longitudinal dyssynchrony metrics.

28. The method of claim 27 wherein the position-with-respect-to-time data is the time to peak displacement of the electrode and the longitudinal dyssynchrony metric corresponds to the difference between the time to peak displacements of the electrodes in the pair.

29. A method comprising:

for a first condition, providing position-with-respect-to-time data for a first electrode located proximate to the coronary sinus and for a second electrode located proximate to the apex of the right ventricle;

for the first condition, determining a maximum displacement vector magnitude between the first electrode and the second electrode;

for the first condition, determining a minimum displacement vector magnitude between the first electrode and the second electrode;

for the first condition, determining a differential magnitude between the maximum displacement vector magnitude and the minimum displacement vector magnitude;

for a second condition, providing position-with-respect-to-time data for the first electrode and for the second electrode;

for the second condition, determining a maximum displacement vector magnitude between the first electrode and the second electrode;

for the second condition, determining a minimum displacement vector magnitude between the first electrode and the second electrode;

for the second condition, determining a differential magnitude between the maximum displacement vector magnitude and the minimum displacement vector magnitude; and

deciding that the larger of the differential magnitudes corresponds to a condition that provides for better cardiac performance.