Accelerometer-based method for cardiac function and therapy assessment

• US 20060095085A1
• Filed: 12/19/2005
• Published: 05/04/2006
• Est. Priority Date: 07/29/2002
• Status: Abandoned Application

• Current Assignee: Ding Sheng He, Frank I. Marcus
• Original Assignee: Ding Sheng He, Frank I. Marcus
• Inventors: Marcus, Frank I., He, Ding Sheng
• Application Number:
  US11/311,039
• Publication Number:
  US 20060095085A1
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• 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 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay
• 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

A method for determining a change in function of a patient'"'"'s heart that includes the steps of collecting seismocardiographic (SCG) data corresponding to a heart motion of the patient'"'"'s heart; determining a hemodynamic parameter based on the SCG data; and comparing the parameter with a predetermined measure of cardiac performance. The system used with the method includes one or more accelerometer sensors, a computer data analysis module, and may also include a 2D and 3D visual graphic display of analytic results, i.e. a Ventricular Contraction Map.

Claims

1. A method for determining a change in function of a patient'"'"'s heart, comprising the steps of:

(a) collecting seismocardiographic (SCG) data from an external surface of a patient corresponding to a heart motion of said patient'"'"'s heart;

(b) determining a hemodynamic parameter based on the SCG data of step (a); and

(c) comparing said parameter of step (b) with a predetermined measure of cardiac performance.

2. The method of claim 1, wherein step (b) further comprises determining one or more parameters selected from the group consisting of isovolumetric contraction time (IVCT), isovolumetric relaxation time (IVCT), and left ventricle ejection time.

3. The method of claim 1, wherein said hemodynamic parameter of step (b) is selected from the group consisting of one or more of the following:

a pre-ejection period, a rate of contraction of left ventricle, a duration of systole, a duration of an isovolumic relaxation period, a rate of change of ventricular pressure, and an ejection fraction.

4. The method of claim 1, wherein the SCG data of step (a) are collected by an accelerometer.

5. The method of claim 1, wherein said SCG data of step (a) are selected from the group consisting of one or more of the following:

acceleration, velocity, and time intervals of valve sounds.

6. The method of claim 1, wherein said predetermined measure of cardiac performance comprises a change in cardiac contractility based on a change in the height or rate of rise of curves based on said SCG data.

7. The method of claim 1, wherein said predetermined measure of cardiac performance comprises a change in SCG data velocity or acceleration during early diastole as an indication of hypertophic cardiomyopathy.

8. The method of claim 1, wherein said predetermined measure of cardiac performance comprises a change in SCG data velocity or acceleration during early diastole of a tilt test as an indication of reflex sympathetic stimulation.

9. The method of claim 1, wherein said hemodynamic parameter comprises a heart valve sound at a designated frequency range.

10. The method of claim 1, further including the step of comparing the SCG data of step (b) with data produced by a non-accelerometer-based technique to determine any correlation between a measure of cardiac function produced by said technique and said SCG data.

11. The method of claim 1, wherein step (b) further comprises subjecting a patient'"'"'s heart to biventricular pacing and determining whether there is a shorter isovolumetric contraction time as an indication that biventricular pacing is increasing heart contraction.

12. The method of claim 1, further including the step of subjecting a patient'"'"'s heart to sub-threshold pacing and determining whether there is a shorter isovolumetric contraction time as an indication that sub-threshold pacing is increasing heart contraction.

13. The method of claim 1, wherein step (a) further comprises providing a plurality of accelerometer sensors for collecting said SCG data.

14. The method of claim 13, wherein step (a) further comprises disposing said plurality of accelerometer sensors upon a neck, a chest apex, and a chest sternum of said patient.

15. The method of claim 1, wherein step (a) comprises collecting SCG data during cardiac motion corresponding to unpaced beats only.

16. A method for testing or evaluation of a cardiac function, comprising the steps of:

(a) collecting seismocardiographic (SCG) data corresponding to heart motion of a patient'"'"'s heart during a non-testing condition;

(b) determining a hemodynamic parameter based on the SCG data of step (a);

(c) imposing a test condition upon said patient;

(d) collecting seismocardiographic (SCG) data corresponding to heart motion of said patient'"'"'s heart during said test condition;

(e) determining said hemodynamic parameter based on the SCG data of step (d); and

(f) comparing information from steps (b) and (e) to determine said cardiac function.

17. The method of claim 16, wherein the SCG data of steps (a) and (d) are collected by an accelerometer sensor.

18. The method of claim 16, wherein said hemodynamic parameter of steps (b) and (e) is selected from the group consisting of one or more of the following:

a pre-ejection period, a rate of contraction of left ventricle, a duration of systole, a duration of an isovolumic relaxation period, a rate of change of ventricular pressure, and an ejection fraction.

19. The method of claim 16, wherein said test condition is selected from the group consisting of stress testing and tilt testing.

20. The method of claim 16, wherein step (e) further comprises determining that heart contractility does not shorten, or the time of contractility lengthens, during a stress test as an indication of coronary blockage.

21. The method of claim 16, wherein step (e) further comprises determining that an amplitude of a rapid filling wave becomes larger during a stress test as an indication of a coronary blockage.

22. A system for determining a change in function of a patient'"'"'s heart, comprising:

means for collecting seismocardiographic (SCG) data from an exterior surface of a said patient corresponding to a heart motion of said patient'"'"'s heart;

means for determining a hemodynamic parameter based on said SCG data; and

a processing device that compares said hemodynamic parameter with a predetermined measure of cardiac performance.

23. The apparatus of claim 22, wherein said means for collecting SCG data comprises an accelerometer.

24. The apparatus of claim 23, wherein said accelerometer is adapted for wireless communication with said means for determining a hemodynamic parameter.

25. The apparatus of claim 22, wherein said means for determining a hemodynamic parameter is adapted for wireless communication with said processing device.