Device and method for the geometric determination of electrical dipole densities on the cardiac wall
Disclosed are devices, a systems, and methods for determining the dipole densities on heart walls. In particular, a triangularization of the heart wall is performed in which the dipole density of each of multiple regions correlate to the potential measured at various locations within the associated chamber of the heart. To create a database of dipole densities, mapping information recorded by multiple electrodes located on one or more catheters and anatomical information is used. In addition skin electrodes may be implemented.
1. A device for creating a database of dipole densities d(y) at the surface of one or more cardiac chambers of a patient, said device comprising:
a first receiver configured to receive mapping information from multiple electrodes located on one or more catheters, the mapping information received when the multiple electrodes are placed in the one or more cardiac chambers;
a second receiver configured to receive anatomical information from at least one imaging instrument configured to produce a geometrical depiction of the one or more cardiac chambers; and
a dipole density module configured to generate the database of dipole densities d(y), wherein the dipole density module determines a dipole density for individual triangle shaped projections onto the cardiac chamber wall, where each triangle projection at a location y contributes {acute over (ω)}(x,y) times the dipole density d(y) to a potential V(x) at a point x, wherein {acute over (ω)}(x,y) is the solid angle for that triangle projection, and where:
a) x represents a series of locations within one or more cardiac chambers; and
b) V(x) is a measured potential at point x, said measured potential recorded by the multiple electrodes.
2. The device of claim 1 wherein said triangle projections are sized such that the dipole density for each triangle projection is substantially constant.
3. The device of claim 1 wherein the dipole density is determined for at least 1000 triangle shaped projections.
4. The device of claim 1 wherein the dipole density is determined by a number of triangle shaped projections, said number determined by the size of a cardiac chamber.
5. The device of claim 1 wherein the multiple electrodes are included in a single catheter.
6. The device of claim 1 wherein the multiple electrodes are included in two or more catheters.
7. The device of claim 1 wherein the imaging instrument is selected from a group consisting of: a computed tomography (CT) instrument; a magnetic resonance imaging (MRI) instrument; an ultrasound instrument; a multiple electrode mapping catheter and mapping system; and combinations thereof.
8. The device of claim 1 wherein the imaging instrument comprises a standard anatomical geometry which is uploaded to the dipole density module.
9. The device of claim 1 wherein the dipole density module includes a mathematical processing element that comprises one or more of:
a computer; an electronic module; a computer program stored in a memory and executable by a processor; a microcontroller; a microprocessor; and combinations thereof.
10. The device of claim 1 wherein the dipole density module implements a progressive algorithm configured to improve at least one of a spatial resolution and a time resolution of the database of dipole densities d(y).
11. The device of claim 1 wherein the dipole density module uses a linear system of equations to determine the database of dipole densities d(y).
12. The device of claim 1 wherein the dipole density module determines a map of dipole densities d(y) at corresponding time intervals.
13. The device of claim 12 wherein the dipole density module generates a synthesis of maps that represents a cascade of activation sequences of each corresponding heart beat from a series of heart beats.
14. The device of claim 1 wherein a number of measured potentials V(x) is in a range of 10 through 10,000 potentials V(x).
15. The device of claim 14 wherein the cardiac chamber wall is divided into regions, wherein each region is represented by a region solid angle with respect to each electrode, and wherein each region solid angle is the sum of the solid angles of the individual triangles in the region.
16. The device of claim 15 wherein a number of regions used to determine the dipole density d(y) is in a range of approximately 10 through 10,000 regions on the cardiac chamber wall.
17. The device of claim 15 wherein the measured potentials V(x) are interpolated to increase the number of regions.
18. The device of claim 17 wherein V(x) is interpolated using splines.
19. The device of claim 1 further comprising:
a third receiver configured to receive mapping information from one or more skin electrodes.
20. The device of claim 19 wherein the dipole density module uses skin electrode signals to calculate and/or recalculate the database of dipole densities d(y).
21. The device of claim 1 wherein the dipole density module calculates and/or recalculates the dipole densities d(y) using the following equations:
W
k
=
∑
l
=
1
L
A
kl
V
l
.
(
1
)
wherein a small sinusoidal voltage V l is applied to each electrode l=1, . . . L on the electrode array in the heart, and the resulting voltages W k , k=1, . . . K is measured at the surface electrodes, which yields the K×L transition matrix A kl ;
V
l
=
∑
n
=
1
N
B
ln
d
n
.
(
2
)
wherein calculating solid angles produces the linear transformation B ln , between the electrode array potentials V l and the dipole densities d n , n=1, . . . N of N regions of the cardiac chamber wall; and
W
k
=
∑
l
=
1
L
∑
n
=
1
N
A
kl
B
ln
d
n
.
(
3
)
where equation (2) above is substituted into equation (1) to form equation (3).
22. The device of claim 21 wherein the dipole density module is configured to solve equations (2) and (3) using regularization techniques.
23. The device of claim 22 wherein the regularization technique is Tikhonov regularization.
24. A system for creating a database of dipole densities d(y) at the surface of one or more cardiac chambers of a patient, said system comprising:
a device for creating a database of dipole densities d(y) at the surface of one or more cardiac chambers of a patient, comprising:
a first receiver configured to receive mapping information from multiple electrodes located on one or more catheters, the mapping information received when the multiple electrodes are placed in the one or more cardiac chambers;
a second receiver configured to receive anatomical information from at least one imaging instrument configured to produce a geometrical depiction of the one or more cardiac chambers; and
a dipole density module configured to generate the database of dipole densities d(y), wherein the dipole density module determines a dipole density for individual triangle shaped projections onto the cardiac chamber wall, where each triangle projection at a location y contributes {acute over (ω)}(x,y) times the dipole density d(y) to a potential V(x) at a point x, wherein {acute over (ω)}(x,y) is the solid angle for that triangle projection, and where:
a) x represents a series of locations within one or more cardiac chambers; and
b) V(x) is a measured potential at point x, said measured potential recorded by the multiple electrodes; and
one or more of:
a multiple electrode catheter;
an imaging instrument;
an ablation device; and
at least one surface or skin electrode.
25. The system of claim 24 comprising a catheter for mapping and ablation.
26. The system of claim 24 comprising an ablation device configured to deliver one or more of: radio frequency (RF) energy; ultrasound energy, and cryogenic energy.
27. A method of creating a database of dipole densities d(y) at the surface of one or more cardiac chambers of a patient, said method comprising:
placing a distal end of an electrode catheter into one of the one or more cardiac chambers of a patient; and
calculating dipole densities d(y) by:
a first receiver receiving mapping information from multiple electrodes located on one or more catheters, the mapping information received when the multiple electrodes are placed in the one or more cardiac chambers;
a second receiver receiving anatomical information from at least one imaging instrument configured to produce a geometrical depiction of the one or more cardiac chambers; and
a dipole density module generating the database of dipole densities d(y), wherein the dipole density module determines a dipole density for individual triangle shaped projections onto the cardiac chamber wall, where each triangle projection at a location y contributes {acute over (ω)}(x,y) times the dipole density d(y) to a potential V(x) at a point x, wherein {acute over (ω)}(x,y) is the solid angle for that triangle projection, and where:
a) x represents a series of locations within one or more cardiac chambers; and
b) V(x) is a measured potential at point x, said measured potential recorded by the multiple electrodes.
28. The method of claim 27 , including using the dipole densities d(y) to locate an origin of abnormal electrical activity of a heart.
29. The method of claims 27 , wherein calculating the dipole densities includes a processor executing a computer program stored in a memory, the computer program embodying an algorithm for generating a table of dipole densities in the memory.