Ablation catheters and associated systems and methods

1. A catheter assembly, comprising:

an elongated body having a proximal region and a distal region extending along a longitudinal axis, wherein the distal region of the body is configured for intravascular delivery to a body lumen of a human patient;

a pre-shaped spiral structure associated with the distal region of the elongated body, wherein the spiral structure is transformable between a low-profile configuration and an expanded configuration; and

a plurality of electrodes spaced apart along the spiral structure, wherein each of the electrodes comprises a wire wound about a corresponding length of the spiral structure,

wherein, when the spiral structure is in the expanded configuration, the spiral structure comprises a plurality of loops longitudinally spaced apart from each other and extending lengthwise along a central loop axis parallel with the longitudinal axis of the elongated body, and

wherein the electrodes are disposed along the loops and configured to apply energy in a lesion pattern along a length of the body lumen of the human patient.

2. The catheter assembly of claim 1 wherein the plurality of electrodes includes a first electrode and a second electrode, and wherein the first electrode and the second electrode are electrically isolated from one another.

3. The catheter assembly of claim 1 wherein the plurality of electrodes includes a first electrode and a second electrode, and wherein, in the expanded configuration, the spiral structure includes a first revolution, and further wherein:

the first electrode extends a first length along the longitudinal axis of the spiral structure; and

the second electrode extends a second length along the longitudinal axis of the spiral structure,

wherein the first length and the second length combined are greater than a length of the first revolution of the spiral structure.

4. The catheter assembly of claim 1 wherein the plurality of electrodes includes a first electrode and a second electrode and wherein, in the expanded configuration, the spiral structure includes a first revolution, and further wherein:

the first electrode extends a first length along the longitudinal axis of the spiral structure; and

the second electrode extends a second length along the longitudinal axis of the spiral structure, and

wherein each of the first length and the second length are less than a length of the first revolution of the spiral structure.

5. The catheter assembly of claim 1 wherein the plurality of electrodes includes a first electrode and a second electrode, and wherein:

the first electrode extends a first length along the longitudinal axis of the spiral structure; and

the second electrode extends a second length along the longitudinal axis of the spiral structure, and

wherein the first length is different than the second length.

6. The catheter assembly of claim 1 wherein the plurality of electrodes includes a first electrode and a second electrode, and wherein:

the first electrode extends a first length along the longitudinal axis of the spiral structure; and

the second electrode extends a second length along the longitudinal axis of the spiral structure, and

wherein the first length is the same as the second length.

7. The catheter assembly of claim 1 wherein the elongated body and the spiral structure include a lumen therethrough, and wherein:

in the low-profile configuration, a stylet or guide wire is positioned in the lumen of the spiral structure; and

in the expanded configuration, the stylet or guide wire is at least partially retracted from the spiral structure toward the proximal region of the elongated body.

8. A catheter assembly, comprising:

an elongated body having a proximal region, a distal region extending along a longitudinal axis, and a lumen therethrough, wherein the distal region of the body is configured for intravascular delivery to a blood vessel of a human patient;

a pre-shaped spiral structure at the distal region of the elongated body, wherein the spiral structure includes a lumen therethrough, wherein the spiral structure is selectively transformable between—

a delivery state wherein a stylet or guide wire is positioned in the lumen of the spiral structure; and

an expanded state wherein the stylet or guide wire is at least partially retracted from the spiral structure toward the proximal region of the elongated body; and

a plurality of energy delivery elements spaced apart along the spiral structure, wherein each energy delivery element comprises a flexible coil wound about a corresponding length of the spiral structure,

wherein the spiral structure, in the expanded state, comprises a plurality of loops spaced longitudinally apart from each other and extending lengthwise along a central loop axis generally parallel with the longitudinal axis of the elongated body, and

wherein the electrodes are disposed along the loops and configured to apply energy in a lesion pattern along a length of the blood vessel of the human patient.

9. The catheter assembly of claim 8 wherein each flexible coil is comprised of a wire.

10. The catheter assembly of claim 9 wherein at least one of the wires is composed of platinum.

11. The catheter assembly of claim 9 wherein at least one of the wires is composed of copper.

12. The catheter assembly of claim 8 wherein the spiral structure is composed of a shape memory material that biases the spiral structure to the expanded state.

13. The catheter assembly of claim 8 wherein the energy delivery elements are arranged on the spiral structure to form the lesion pattern of discrete, non-continuous lesions at a target treatment site within the blood vessel when the spiral structure is in the expanded state.

14. The catheter assembly of claim 8 , further comprising a retractable sheath at least partially surrounding the distal region of the elongated body when the spiral structure is in the delivery state.

15. The catheter assembly of claim 8 wherein the elongated body is configured for over-the-wire or rapid exchange delivery techniques.

16. The catheter assembly of claim 8 wherein the spiral structure comprises a generally uniform diameter in the expanded state.

17. The catheter assembly of claim 8 wherein the plurality of energy delivery elements includes a first flexible coil electrode and a second flexible coil electrode, and wherein the first electrode and the second electrode are electrically isolated from one another.

18. The catheter assembly of claim 8 wherein the plurality of energy delivery elements includes a first energy delivery element and a second energy delivery element, and wherein, in the expanded state, the spiral structure includes a first revolution, and further wherein:

the first energy delivery element extends a first length along the longitudinal axis of the spiral structure; and

the second energy delivery element extends a second length along the longitudinal axis of the spiral structure, and

wherein the first length and the second length combined are greater than a length of the first revolution of the spiral structure.

19. The catheter assembly of claim 8 wherein the plurality of energy delivery elements includes a first energy delivery element and a second energy delivery element, and wherein, in the expanded state, the spiral structure includes a first revolution, and further wherein:

the first energy delivery element extends a first length along the longitudinal axis of the spiral structure; and

the second energy delivery element extends a second length along the longitudinal axis of the spiral structure, and

wherein each of the first length and the second length are less than a length of the first revolution of the spiral structure.

20. The catheter assembly of claim 8 wherein the plurality of energy delivery elements includes a first energy delivery element and a second energy delivery element, and wherein:

the first energy delivery element extends a first length along the longitudinal axis of the spiral structure; and

the second energy delivery element extends a second length along the longitudinal axis of the spiral structure,

wherein the first length is different than the second length.

21. The catheter assembly of claim 8 wherein the plurality of energy delivery elements includes a first energy delivery element and a second energy delivery element, and wherein:

the first energy delivery element extends a first length along the longitudinal axis of the spiral structure; and

the second energy delivery element extends a second length along the longitudinal axis of the spiral structure, and

wherein the first length is the same as the second length.