Double bipolar configuration for atrial fibrillation annotation

1. A method, comprising the steps of:

inserting a probe into a heart of a living subject, the probe having a plurality of unipolar electrodes;

for a plurality of pairs of unipolar electrodes, recording a bipolar electrogram from electrical signals received from a pair of unipolar electrodes at a location in the heart and a unipolar electrogram from one of the electrodes of the pair of electrodes;

defining a time interval comprising a window of interest wherein a rate of change in a potential of the bipolar electrogram exceeds a predetermined value;

establishing an annotation in the unipolar electrogram, wherein the annotation denotes a maximum rate of change in a potential of the unipolar electrogram within the window of interest;

assigning a quality value to the annotation; and

generating a 3-dimensional map of a portion of the heart wherein the map includes the annotation and the quality value thereof.

2. The method according to claim 1 , wherein recording a bipolar electrogram comprises establishing a double bipolar electrode configuration of electrodes, the double bipolar electrode configuration comprising a first differential signal from a first pair of unipolar electrodes and a second differential signal from a second pair of unipolar electrodes, wherein the bipolar electrogram is measured as a time-varying difference between the first differential signal and the second differential signal.

3. The method according to claim 1 , wherein establishing an annotation comprises computing a wavelet transform of the unipolar electrogram.

4. The method according to claim 3 , further comprising producing a scalogram of the wavelet transform and determining the maximum rate of change in the scalogram.

5. The method according to claim 1 , further comprising the steps of:

identifying from the quality value that the annotation is a qualified annotation that meets predetermined blocking criteria; and

indicating on the map that the qualified annotation is at or near a blocked region of the heart.

6. The method according to claim 1 , wherein establishing an annotation comprises removing ventricular far field components from the unipolar electrogram.

7. The method according to claim 1 , wherein establishing an annotation comprises determining if a temporal cycle length of the unipolar electrogram at the annotation lies within predefined statistical bounds for temporal cycle lengths of other annotations.

8. The method according to claim 1 , further comprising the steps of:

adjusting the quality value of the annotation according to at least one of a quality value, inter-annotation distance and timing of another annotation.

9. The method according to claim 8 , wherein the other annotation was generated from another unipolar electrogram that was read from another of the electrodes.

10. The method according to claim 1 , further comprising the step of filtering the unipolar electrogram by an amount sufficient to reduce noise to a predetermined level, wherein assigning a quality value comprises determining the amount.

11. An apparatus, comprising:

an intra-body probe having a plurality of unipolar electrodes, the probe being configured to contact tissue in a heart;

a display; and

a processor, which is configured to receive an electrical signal from the plurality of unipolar electrodes and, for a plurality of pairs of unipolar electrodes, to perform the steps of:

recording a bipolar electrogram from a pair of unipolar electrodes and a unipolar electrogram from one of the electrodes of the pair of unipolar electrodes;

defining a time interval comprising a window of interest wherein a rate of change in a potential of the bipolar electrogram exceeds a predetermined value;

establishing an annotation in the unipolar electrogram, wherein the annotation denotes a maximum rate of change in a potential of the unipolar electrogram within the window of interest;

assigning a quality value to the annotation; and

generating on the display a 3-dimensional map of a portion of the heart wherein the map includes the annotation and the quality value thereof.

12. The apparatus according to claim 11 , wherein recording a bipolar electrogram comprises establishing a double bipolar electrode configuration of electrodes, the double bipolar electrode configuration comprising a first differential signal from a first pair of unipolar electrodes and a second differential signal from a second pair of unipolar electrodes, wherein the bipolar electrogram is measured as a time-varying difference between the first differential signal and the second differential signal.

13. The apparatus according to claim 11 , wherein establishing an annotation comprises computing a wavelet transform of the unipolar electrogram.

14. The apparatus according to claim 13 , further comprising producing a scalogram of the wavelet transform and determining the maximum rate of change in the scalogram.

15. The apparatus according to claim 11 , further comprising the steps of:

identifying from the quality value that the annotation is a qualified annotation that meets predetermined blocking criteria; and

indicating on the map that the qualified annotation is at or near a blocked region of the heart.

16. The apparatus according to claim 11 , wherein establishing an annotation comprises removing ventricular far field components from the unipolar electrogram.

17. The apparatus according to claim 11 , wherein establishing an annotation comprises determining if a temporal cycle length of the unipolar electrogram at the annotation lies within predefined statistical bounds for temporal cycle lengths of other annotations.

18. The apparatus according to claim 11 , wherein the probe has multiple rays, each of the rays having at least one electrode.

19. The apparatus according to claim 11 , wherein the probe is a basket catheter having multiple ribs, each of the ribs having at least one electrode.