Impedance shift and drift detection and correction

1. A computer implemented method for detection of an impedance shift in an impedance based coordinate system, comprising:

receiving an impedance location of an electrode disposed on a catheter in an impedance based coordinate system and a magnetic location of a magnetic position sensor disposed on the catheter in a magnetic based coordinate system;

computing a transformed impedance location of the magnetic position sensor using an electromagnetic registration between the impedance based coordinate system and the magnetic based coordinate system;

determining a difference between the transformed impedance location of the magnetic position sensor and the magnetic location of the magnetic position sensor;

computing a magnitude of the difference between the impedance location of the magnetic position sensor and the magnetic location of the magnetic position sensor;

computing a statistical significance of the difference between the transformed impedance location of the magnetic position sensor and the magnetic location of the magnetic position sensor;

determining that an impedance shift exists if the magnitude of the difference exceeds a threshold and the statistical significance of the difference exceeds a threshold; and

filtering the impedance location of the electrode disposed on the catheter based on a confidence metric associated with the impedance location of the electrode, wherein the confidence metric is based on the impedance location of the electrode with respect to a location of the electromagnetic registration.

2. The method of claim 1 , further comprising:

assigning a low confidence metric when the impedance location of the electrode is outside of a location of the electromagnetic registration; and

filtering out the impedance location of the electrode based on the assigned low confidence metric.

3. The method of claim 1 , wherein the method includes:

determining a mean of the difference over a first time scale; and

determining a covariance of the difference over a second time scale, wherein the second time scale is a longer time scale than the first time scale.

4. The method of claim 3 , wherein the method includes computing the statistical significance based on the mean of the difference and the covariance of the difference.

5. The method of claim 3 , wherein the method includes computing a magnitude of the mean of the difference over the first time scale.

6. The method of claim 3 , further comprising applying an electromagnetic registration to transform a shifted impedance location of the electrode from a shifted impedance based coordinate system into an unshifted magnetic location of the electrode in a magnetic based coordinate system, using the electromagnetic registration, in response to the determination of the impedance shift.

7. The method of claim 1 , wherein the electromagnetic registration is computed based on an impedance location of an electrode disposed on a catheter in the impedance based coordinate system and a magnetic location of a magnetic position sensor disposed on the catheter in the magnetic based coordinate system.

8. The method of claim 1 , further comprising providing an indication to a user to take a corrective action in response to determining that the impedance shift exists.

9. The method of claim 1 , wherein the electrode and the magnetic position sensor are disposed on a same catheter.