Apparatus and method for self-guided ablation

Abstract

An ablation catheter comprises an elongate catheter body and a branch electrode element. The elongate catheter body has a central axis, a distal end, and a proximal end. The elongate catheter body is configured to be steered within a heart chamber. The branch electrode element has a base end and a working end or tip. The base end is secured to the elongate catheter body at a location spaced proximally of the distal end and an effector on the working end. The branch electrode element is configured to evert when the distal end of the elongate catheter body is in a pulmonary vein ostium or os so that the effector can be selectively engaged against locations surrounding the pulmonary vein os which differ in radial direction and distance. One or more of linear or curved ablation patterns are generated on tissue adjacent the pulmonary vein os with the effector.

1 .- 40 . (canceled) 
     
     
         41 . A method for tissue ablation, said method comprising:
 anchoring a distal end of a catheter in an opening into a body cavity; and   deploying a branch electrode element from the catheter;   positioning an ablation element of the branch electrode to one or more tissue locations surrounding the opening into the body cavity, and   ablating the one or more tissue locations with the ablation element.   
     
     
         42 . The method of  claim 41 , further comprising determining one or more of an orientation or position of the ablation element. 
     
     
         43 . The method of  claim 42 , wherein the one or more of the orientation or position of the ablation element is determined with a sensor at the distal end of the catheter. 
     
     
         44 . The method of  claim 41 , wherein anchoring the distal end of the catheter in the opening into the body cavity comprises deploying a centering mechanism from the distal end of the catheter. 
     
     
         45 . The method of  claim 41 , wherein the catheter comprises a main body with a central lumen. 
     
     
         46 . The method of  claim 41 , wherein anchoring the distal end of the catheter in the opening into the body cavity comprises expanding an expandable element in or adjacent the opening into the body cavity. 
     
     
         47 . The method of  claim 46 , wherein the expandable element comprises a wire cage or an inflatable balloon. 
     
     
         48 . The method of  claim 41 , further comprising mapping tissue surrounding the opening into the body cavity with one or more mapping electrodes disposed on the distal end of the catheter. 
     
     
         49 . The method of  claim 41 , wherein deploying the branch electrode element from the catheter comprises independently controlling the radial direction and radial distance of the ablation element from the catheter. 
     
     
         50 . The method of  claim 41 , wherein ablating the one or more tissue locations with the ablation element comprises generating an ablation pattern on tissue adjacent the opening into the body cavity. 
     
     
         51 . The method of  claim 50 , wherein generating the ablation pattern comprises rotating the catheter to generate a curved ablation pattern with the ablation element. 
     
     
         52 . The method of  claim 51 , wherein generating the ablation pattern comprises axially translating the catheter to generate a linear ablation pattern with the ablation element. 
     
     
         53 . The method of  claim 51 , wherein generating the ablation pattern comprises adjusting an amount of eversion of the branch electrode element relative to the catheter. 
     
     
         54 . The method of  claim 51 , wherein generating the ablation pattern comprises delivering energy from the ablation element to the tissue. 
     
     
         55 . The method of  claim 54 , wherein the energy delivered comprises one or more of RF energy or thermal energy. 
     
     
         56 . The method of  claim 54 , wherein generating the ablation pattern comprises delivering a cooling fluid for cryoablation. 
     
     
         57 . The method of  claim 41 , wherein the ablation element comprises an ablation electrode. 
     
     
         58 . The method of  claim 57 , wherein the ablation electrode is operable in a monopolar mode. 
     
     
         59 . The method of  claim 57 , wherein the ablation electrode is operable in a bipolar mode. 
     
     
         60 . The method of  claim 41 , further comprising determining a tissue contact force between the ablation element and tissue surrounding the opening into the body cavity. 
     
     
         61 . The method of  claim 60 , wherein the tissue contact force is determined with a sensor adjacent the ablation element. 
     
     
         62 . The method of  claim 61 , wherein the body cavity is selected from the group comprising a nasal cavity, an oral cavity, a throat, an esophagus, a stomach, a small intestine, a large intestine, a colon, a rectum, a bronchus, a bladder, a ureter, a urethra, a vagina, a cervix, a uterus, a fallopian tube, a heart chamber, a heart ventricle, a heart atrium, an aorta, a vena cava, an abdominal aorta, a renal artery, a femoral artery, an ascending aorta, a subclavian artery, a carotid artery, a jugular vein, a subclavian vein, a cephalic vein, a femoral vein, a renal vein, an inferior vena cava, or a pulmonary artery. 
     
     
         63 . The method of  claim 61 , wherein anchoring the distal end of the catheter in the opening of the body cavity comprises anchoring the distal end of the catheter in the pulmonary vein os. 
     
     
         64 . The method of  claim 63 , wherein ablating the one or more tissue locations with the ablation element comprises ablating one or more tissue locations at or around the pulmonary vein os.