Cardiac mapping catheter

1. A catheter comprising:

an elongate catheter body having a distal end and a proximal end;

a proximal handle segment having an articulation control and a deployment control, said proximal handle segment connected to said proximal end;

an intermediate segment connected to said handle segment;

a deflectable segment connected to said intermediate segment, said deflectable segment adapted to articulate in a plane through an angle in response to said articulation control;

a distal array segment connected to said deflectable segment, said distal array segment including a deployable electrode array that can move from a first retracted position to a second deployed position;

a deployment mechanism coupled to said deployment control for coupling motion of said deployment control to said deployable electrode array, the deployment mechanism comprising:

an elongate rotatable member coupled to said deployment control;

a first threaded member disposed and anchored in said distal array segment;

a second threaded member coupled to said elongate rotatable member;

said first and second threaded members adapted for engagement by rotation of said rotatable member to cause the electrode array to deploy into said second deployed position and maintain the distal array in the second deployed position during articulation of deflectable segment.

2. The catheter of claim 1 wherein:

the relative position of said second threaded member and said first threaded member determines the deployment position of said distal electrode array; and

changes in rotatable member tension do not alter the relative position of said first and second members thereby rendering deployment independent of articulation.

3. The catheter of claim 1 , wherein

said deployable electrode array is formed from a flexible printed circuit slit to form splines and rolled about the major axis, the splines of the flexible printed circuit including first regions having a first stiffness and second regions that include one or more stiffener layers and have a second stiffness that is greater than the first stiffness, the stiffness of the first and second regions at least partially determining the shape of the electrode array in the deployed position, the stiffener layers comprising a material selected from the group consisting of polyimide, PEEK, and nickel titanium alloy.

4. The catheter of claim 3 wherein:

each spline in said deployable electrode array has a non-uniform shape characteristic resulting in control of the shape of the electrode array in the deployed position.

5. The catheter of claim 1 wherein:

said distal array segment has a uniform and symmetrical distribution of electrodes in the array.

6. The catheter of claim 1 wherein:

said deployable electrode array comprises bonding apertures at an end of the array adapted for encapsulation to form and retain a tubular shape.

7. The catheter of claim 1 wherein:

said deployable electrode array comprises bonding apertures at an end of the array adapted for encapsulation by a thermoplastic materials to form and retain a tubular shape.

8. The catheter of claim 1 wherein:

said deployable electrode array is formed from a flexible printed circuit comprising:

an insulating layer;

a first metal layer supported by a first surface of the insulating layer and a second metal layer supported by a second surface of the insulating layer, the first and second metal layers comprising an electrode material selected from the group consisting of: gold, stainless steel, platinum, platinum-iridium, titanium nitride, platinum black and iridium-oxide;

an overcoat layer supported by the second metal layer configured to insulate the second metal layer;

a first stiffener layer supported by the overcoat layer; and

a second stiffener layer that is separate from the first stiffener layer and disposed on portions of the first stiffener layer to form the second regions that have the second stiffness that is greater than the first stiffness.

9. The catheter of claim 1 further comprising:

a fluid delivery lumen to flood the distal array segment with a fluid injected into the catheter.

10. The catheter of claim 1 further comprising:

a radio-opaque pattern applied to the distal array segment such that the pattern changes during deployment to provide a discernable radiographic image to confirm deployment.

11. The catheter of claim 1 further comprising:

a tracking sensor located near said distal array segment.

12. The catheter of claim 1 further comprising:

a set of current injecting tracking electrodes located in said distal array segment.

13. The catheter of claim 1 further including:

an articulation mechanism coupled to said articulation control for coupling motion of said articulation control to said deflectable segment to cause the deflectable segment to symmetrically bi-directionally articulate in a plane through an angle.

14. The catheter of claim 1 further including:

an articulation mechanism coupled to said articulation control for coupling motion of said articulation control to said deflectable segment to cause the deflectable segment to asymmetrically bi-directional articulate in a plane through an angle.

15. The catheter of claim 1 , wherein

said electrode array is formed from a flexible printed circuit, the flexible printed circuit comprising:

an insulating layer comprising a first side and a second side;

a first metallization layer coated with iridium oxide on the first side of the insulating layer, the first metallization layer configured to increase the surface area of the first metallization layer;

a second metallization layer on the second side of the insulating layer; and

an electrical connection between the first metallization layer and the second metallization layer.

16. The catheter of claim 15 , wherein first metallization layer comprises a plurality of metal layers.

17. The catheter of claim 15 , wherein first metallization layer comprises:

a titanium layer supported by the insulating layer;

a gold layer supported by the titanium layer; and

an iridium-oxide layer supported by the gold layer.

18. The catheter of claim 15 , wherein the first metallization layer comprises:

an interface layer supported by the insulating layer;

a conductive layer comprising a copper or gold layer supported by the insulating layer; and

an iridium-oxide layer supported by the conductive layer.

19. The catheter of claim 15 , wherein the first metallization layer comprises:

a conductive layer comprising a copper or gold layer; and

an iridium-oxide layer supported by the conductive layer.

20. The catheter of claim 15 , wherein second metallization layer comprises a plurality of metal layers.

21. The catheter of claim 15 , wherein the electrical connection between the first metallization layer and the second metallization layer comprises a metallization layer in a via that extends through the first metallization layer, the insulating layer, and the second metallization layer.