Tracking coordinates of electrodes with Bezier curves
A technique is described herein. The technique includes receiving endpoint location data and spline tangent data from a pair of position sensors mounted on opposite ends of a distal tip of a catheter, wherein said distal tip includes a plurality of flexible splines and a plurality of electrodes disposed on each of the flexible splines and wherein said endpoint location data and spline tangent data is received while said distal tip is positioned within a heart chamber; based on said endpoint location data and spline tangent data, calculating Bezier curve control points; based on the Bezier curve control points, determining estimated positions of said plurality of electrodes; and updating an electro-anatomical map of said heart chamber that is rendered on a display based on the estimated positions determined.
1 . A method for improving cardiac mapping during a cardiac procedure, the method comprising:
receiving endpoint location data during the cardiac procedure based on measurements taken with a first sensor mounted at a proximal end of a distal tip of a catheter and a second sensor mounted at a distal end of the distal tip, wherein the distal tip includes a plurality of flexible splines each coupled to a plurality of electrodes;
determining a deflection angle of the second sensor relative to a longitudinal axis of the distal tip;
determining spline tangent data comprising, for each of the plurality of flexible splines, a tangent at a proximal portion of the spline;
determining, for each of the plurality of flexible splines, a tangent at a distal portion of the spline based on the deflection angle using a stored mapping between a circumferential anchor index of the spline and a deflection frame of the second sensor;
for each of the plurality of flexible splines, calculating control points of a respective Bezier curve based on the endpoint location data, the proximal-portion tangent from the spline tangent data, and the distal-portion tangent determined from the deflection angle, wherein each respective Bezier curve has the proximal end and the distal end of the distal tip as endpoints and is solved by enforcing (i) the proximal-portion and distal-portion tangents as endpoint tangent constraints and (ii) an arc-length constraint equal to a known length of the corresponding flexible spline, and wherein calculating the control points is performed without using electrode positions as fit points;
determining estimated positions of each of the plurality of electrodes based on the calculated control points; and
displaying, during the cardiac procedure, an electro-anatomical map of a heart chamber based on the estimated positions.
2 . The method of claim 1 , wherein the distal tip is a catheter basket, wherein the endpoint location data comprises locations of the proximal end and the distal end of the distal tip, and wherein each respective Bezier curve uses the proximal end and the distal end as its endpoints.
3 . The method of claim 1 , wherein determining the tangent at the distal portion based on the deflection angle is performed for each of the plurality of flexible splines using the stored mapping between the circumferential anchor index and the deflection frame.
4 . The method of claim 1 , wherein the known length is a known length of each of the plurality of flexible splines as used to enforce the arc-length constraint for the respective Bézier curves in claim 1 .
5 . The method of claim 1 , wherein determining:
the estimated positions of the plurality of electrodes comprises generating geometry points from the respective Bézier curve control points and determining the estimated electrode positions by arc-length parameterization along each respective curve based on stored along-spline electrode indices.
6 . The method of claim 1 , wherein the first sensor and the second sensor each comprise a magnetic position sensor configured to sense position in three dimensions.
7 . The method of claim 1 , wherein the endpoint location data includes locations of the first sensor and the second sensor, and wherein calculating the control points for each respective Bézier curve uses the locations of the first and second sensors as the endpoints of the curve.
8 . The method of claim 1 , wherein calculating the control points and determining the estimated positions are performed without using any electrode electrical measurements, including impedance-based or electrogram-derived positions, as fit points.
9 . A system for improving cardiac mapping during a cardiac procedure, the system comprising:
a communication interface that is communicatively coupled to a catheter that includes a first sensor mounted at a proximal end of a distal tip of the catheter and a second sensor mounted at a distal end of the distal tip, wherein the distal tip includes a plurality of flexible splines each coupled to a plurality of electrodes;
a display;
a memory; and
one or more processors communicatively coupled to the communication interface, the display, and the memory, the one or more processors collectively configured to:
receive, using the communication interface and during the cardiac procedure, endpoint location data based on measurements taken with the first sensor and the second sensor while the distal tip is positioned within a heart chamber;
determine a deflection angle of the second sensor relative to a longitudinal axis of the distal tip;
determine spline tangent data comprising, for each of the plurality of flexible splines, a tangent at a proximal portion of, the spline;
determine, for each of the plurality of flexible splines, a tangent at a distal portion of the spline based on the deflection angle using a stored mapping between a circumferential anchor index of the spline and deflection frame of the second sensor;
for each of the plurality of flexible splines, calculate control points of a respective Bezier curve based on the endpoint location data, the proximal-portion tangent from the spline tangent data, and the distal-portion tangent determined from the deflection angle, wherein each respective Bezier curve has the proximal end and the distal end of the distal tip as endpoints and is solved by enforcing (i) the proximal-portion and distal-portion tangents as endpoint tangent constraints and (ii) an arc-length constraint equal to a known length of the corresponding flexible spline, and wherein calculating the control points is performed without using electrode positions as fit points;
determine estimated positions of each of the plurality of electrodes based on the calculated control points; and
render, during the cardiac procedure, an electro-anatomical map of the heart chamber on the display based on the estimated positions.
10 . The system of claim 9 , wherein the distal tip is a catheter basket, wherein the endpoint location data comprises locations of the proximal end and the distal end of the distal tip, and wherein each respective Bézier curve uses the proximal end and the distal end as its endpoints.
11 . The system of claim 9 , wherein the one or more processors are further configured:
such that determining the tangent at the distal portion based on the deflection angle is performed for each of the plurality of flexible splines using the stored mapping between the circumferential anchor index and the deflection frame.
12 . The system of claim 9 , wherein each respective Bezier curve is constrained to the known length of the corresponding flexible spline as recited in claim 8 , the known length being stored in the memory.
13 . The system of claim 9 , wherein determining the estimated positions of the plurality of electrodes comprises generating geometry points from the respective Bezier curve control points and determining the estimated electrode positions:
by arc-length parameterization along each respective curve based on stored along-spline electrode indices.
14 . The system of claim 9 , wherein the first sensor and the second sensor each comprise a magnetic position sensor configured to sense position in three dimensions.
15 . The system of claim 14 , further comprising a location pad fixedly located outside of a patient in which the catheter is inserted, wherein the location pad is configured to generate magnetic fields that are sensed by the magnetic position sensors.
16 . A non-transitory computer-readable medium storing instructions for improving cardiac mapping during a cardiac procedure, the instructions when collectively executed by one or more processors of a console, cause the console to perform operations comprising:
receiving endpoint location data during the cardiac procedure based on measurements taken with a first sensor mounted at a proximal end of a distal tip of a catheter and a second sensor mounted at a distal end of the distal tip, wherein the distal tip includes a plurality of flexible splines each coupled to a plurality of electrodes;
determining a deflection angle of the second sensor relative to a longitudinal axis of the distal tip;
determining spline tangent data comprising, for each of the plurality of flexible splines, a tangent at a proximal portion of the spline;
determining, for each of the plurality of flexible splines, a tangent at a distal portion of the spline based on the deflection angle using a stored mapping between a circumferential anchor index of the spline and a deflection frame of the second sensor;
for each of the plurality of flexible splines, calculating control points of a respective Bezier curve based on the endpoint location data, the proximal-portion tangent from the spline tangent data, and the distal-portion tangent determined from the deflection angle, wherein each respective Bézier curve has the proximal end and the distal end of the distal tip as endpoints and is solved by enforcing (i) the proximal-portion and distal-portion tangents as endpoint tangent constraints and (ii) an arc-length constraint equal to a known length of the corresponding flexible spline, and wherein calculating the control points is performed without using electrode positions as fit points;
determining estimated positions of each of the plurality of electrodes based on the calculated control points; and
displaying, during the cardiac procedure, an electro-anatomical map of a heart chamber based on the estimated positions.
17 . The non-transitory computer-readable medium of claim 16 , wherein the distal tip is a catheter basket, and wherein the endpoint location data comprises locations of the proximal end and the distal end of the distal tip.
18 . The non-transitory computer-readable medium of claim 16 , wherein determining the tangent at the distal portion based on the deflection angle is performed for each of the plurality of flexible splines using the stored mapping between the circumferential anchor index and the deflection frame.
19 . The non-transitory computer-readable medium of claim 16 , wherein each respective Bézier curve is constrained to the known length of the corresponding flexible.
20 . The non-transitory computer-readable medium of claim 16 , wherein determining the estimated positions of the plurality of electrodes comprises generating geometry points from the respective Bézier curve control points and determining the estimated electrode positions by arc-length parameterization along each respective curve based on stored along-spline electrode indices.