ASSESSING INTRA-CARDIAC ACTIVATION PATTERNS

• US 20120284003A1
• Filed: 05/02/2012
• Published: 11/08/2012
• Est. Priority Date: 05/03/2011
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gosh, Subham, Gillberg, Jeffrey M., Stadler, Robert W.
• Granted Patent: US 8,972,228 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61N 1/0476 Array electrodes (including any electrode arrangement with more than one electrode for at least one of the polarities)
• CPC Class Codes: A61N 1/0484 Garment electrodes worn by the patient
• 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 1/3682 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

Techniques for evaluating cardiac electrical dyssynchrony are described. In some examples, an activation time is determined for each of a plurality of torso-surface potential signals. The dispersion or sequence of these activation times may be analyzed or presented to provide variety of indications of the electrical dyssynchrony of the heart of the patient. In some examples, the locations of the electrodes of the set of electrodes, and thus the locations at which the torso-surface potential signals were sensed, may be projected on the surface of a model torso that includes a model heart. The inverse problem of electrocardiography may be solved to determine electrical activation times for regions of the model heart based on the torso-surface potential signals sensed from the patient.

Claims

1. A method comprising:

determining a location of each of a plurality of electrodes distributed on a torso of a patient;

projecting, with a processing unit, the locations of the plurality of electrodes onto a surface of a model torso;

receiving, by the processing unit, a torso-surface potential signal sensed by each of the plurality of electrodes;

projecting, by the processing unit, each of the torso-surface potential signals onto a respective location on the surface of the model torso based on the determined locations of the electrodes; and

determining, by the processing unit, a set of cardiac activation times for a model heart within the model torso based on the projected torso-surface potential signals and a location of the model heart within the model torso.

2. The method of claim 1, further comprising selecting the model torso and model heart from a plurality of model torsos and model hearts based on at least one characteristic of the patient.

3. The method of claim 2, wherein selecting the model torso and model heart from the plurality of model torsos and model hearts based on at least one characteristic of the patient comprises selecting the model torso and model heart from the plurality of model torsos and model hearts based on manual or semi-automatic segmentation and registration of medical images taken from the patient.

4. The method of claim 2, wherein the model hearts and the model torsos are constructed by manual or semi-automatic image segmentation of medical images from subjects other than the patient.

5. The method of claim 2, wherein the model torsos are differentiated by at least one of gender or size, and the model hearts are differentiated by at least one of size or disease state.

6. The method of claim 1, wherein determining a set of cardiac activation-times for the model heart comprises calculating a set of epicardial potentials from the projected torso-surface potentials.

7. The method of claim 6, wherein calculating the set of epicardial potentials comprises assuming a source-less volume conductor between the model heart and the model torso in an inverse Cauchy problem for Laplace'"'"'s equation.

8. The method of claims 6, wherein calculating the set of epicardial potentials comprises:

assuming an analytic relationship between the projected torso-surface potentials and a cardiac transmembrane potential;

simulating torso-surface potentials based on the analytic relationship; and

identifying epicardial potentials that minimize the least square difference between the projected torso-surface potentials and the simulated torso-surface potentials.

9. A system comprising:

a plurality of electrodes distributed on a torso of a patient; and

a processing unit configured to project the locations of the plurality of electrodes onto a surface of a model torso, receive a torso-surface potential signal sensed by each of the plurality of electrodes, projecting each of the torso-surface potential signals onto a respective location on the surface of a model torso based on the determined locations of the electrodes, and determine a set of cardiac activation times for a model heart within the model torso based on the projected torso-surface potential signals and a location of the model heart within the model torso.

10. The system of claim 9, wherein the processing unit is configured to select the model torso and model heart from a plurality of model torsos and model hearts based on at least one characteristic of the patient.

11. The system of claim 10, wherein the processing unit is configured to select the model torso and model heart based on manual or semi-automatic segmentation and registration of medical images taken from the patient.

12. The system of claim 10, wherein the model hearts and the model torsos are constructed by manual or semi-automatic image segmentation of medical images from subjects other than the patient.

13. The system of claim 10, wherein the model torsos are differentiated by at least one of gender or size, and the model hearts are differentiated by at least one of size or disease state.

14. The system of claim 9, wherein the processing unit is configured to calculate a set of epicardial potentials from the projected torso-surface potentials, and determine the set of cardiac activation times based on the set of epicardial potentials.

15. The system of claim 14, wherein the processing unit is configured to assume a source-less volume conductor between the model heart and the model torso in an inverse Cauchy problem for Laplace'"'"'s equation.

16. The system of claims 14, wherein the processing unit is configured to:

assume an analytic relationship between the projected torso-surface potentials and a cardiac transmembrane potential;

simulate torso-surface potentials based on the analytic relationship; and

identify epicardial potentials that minimize the least square difference between the projected torso-surface potentials and the simulated torso-surface potentials.

17. A computer-readable storage medium comprising instructions that, when executed, cause a processor to:

project locations of a plurality of electrodes distributed on a torso of a patient onto a surface of a model torso;

receive a torso-surface potential signal sensed by each of the plurality of electrodes;

project each of the torso-surface potential signals onto a respective location on the surface of the model torso based on the determined locations of the electrodes; and

determine a set of cardiac activation times for a model heart within the model torso based on the projected torso-surface potential signals and a location of the model heart within the model torso.