Lasso catheter with rotating ultrasound transducer

1. A medical device, comprising:

an insertion shaft, having a longitudinal axis and having a distal end terminating in a distal tip adapted for insertion into a body of a patient;

a resilient end section fixed to and extending from the distal tip of the insertion shaft, the resilient end section defining an arc residing in a plane, the plane oriented obliquely relative to the longitudinal axis, the arc having a center of curvature coincident with the longitudinal axis and a radius of curvature about the longitudinal axis, and which has one or more electrodes disposed along the end section;

an ultrasound transducer, which is fixed to the distal end and is configured to image a vicinity of the arc using ultrasound waves, the ultrasound transducer having a field of view that is inclined relative to the axis and coincides with the vicinity of the arc when the insertion shaft is rotated about the axis; and

a rotation mechanism that is configured to rotate the ultrasound transducer about the axis independently of rotation of the insertion shaft.

2. The medical device according to claim 1 , wherein the ultrasound transducer has an annular field of view that is collinear with the axis and coincides with the vicinity of the arc.

3. The medical device according to claim 1 , wherein one or more of the electrodes are configured to sense an electrical potential on cardiac tissue when the end section is positioned against the tissue.

4. The medical device according to claim 1 , wherein the end section comprises a position transducer, and comprising a position sensing system, which is configured to communicate with the position transducer so as to determine a position of the end section within the body.

5. The medical device according to claim 1 , wherein one or more of the electrodes comprise ablation electrodes for ablating tissue when the end section is positioned against the tissue, and wherein the ultrasound transducer is configured to image the ablated tissue.

6. The medical device according to claim 5 , and comprising a Radio Frequency (RF) generator that is coupled to supply RF energy to the ablation electrodes so as to ablate the tissue.

7. A method for medical treatment, comprising:

inserting into a body of a patient a probe comprising an insertion shaft, having a longitudinal axis and a distal end terminating in a distal tip, and a resilient end section fixed to and extending from the distal tip of the insertion shaft, the resilient end section defining an arc residing in a plane, the plane oriented obliquely to the longitudinal axis, the arc having a center of curvature on the longitudinal axis and a radius of curvature about the longitudinal axis, with electrodes disposed at respective locations along the end section;

advancing the probe axially so that the end section engages a tissue in the body along the arc, causing at least some of the electrodes to contact the tissue simultaneously and ablate the contacted tissue; and

imaging the ablated tissue by irradiating a vicinity of the arc using an ultrasound transducer that is fixed to the distal end, the ultrasound transducer having a field of view that is inclined relative to the axis and coincides with the vicinity of the arc when the insertion shaft is rotated about the axis, the probe having a rotation mechanism that is configured to rotate the ultrasound transducer about the axis independently of rotation of the insertion shaft.

8. The method according to claim 7 , wherein irradiating the vicinity of the arc comprises transmitting ultrasound energy from the ultrasound transducer in an annular field of view that is collinear with the axis and coincides with the vicinity of the arc.

9. The method according to claim 7 , and comprising sensing an electrical potential on the contacted tissue using one or more of the electrodes.

10. The method according to claim 7 , and comprising communicating with a position transducer in the end section to determine a position of the end section within the body.

11. The method according to claim 7 , wherein irradiating the vicinity of the arc comprises receiving an ultrasound wave that is reflected from the tissue, and producing and displaying ultrasound images of the tissue based on the reflected ultrasound wave.

12. The method according to claim 7 , wherein irradiating the vicinity of the arc comprises receiving an ultrasound wave that is reflected from the tissue, and estimating a characteristic of the tissue based on the reflected ultrasound wave.

13. The method according to claim 7 , wherein irradiating the vicinity of the arc comprises transmitting ultrasound energy from the ultrasound transducer in a field of view that is inclined relative to the axis and coincides with the vicinity of the arc when the insertion shaft is rotated about the axis.

14. The method according to claim 13 , and comprising rotating the ultrasound transducer about the axis independently of rotation of the insertion shaft.

15. The method according to claim 13 , and comprising supplying RF energy to the electrodes so as to ablate the tissue.