Dual node multiray electrode catheter

A method for treatment comprising:

• providing a catheter with an elongated catheter body having proximal and distal ends and a dual node multiray electrode assembly at the distal end of the catheter body, wherein the dual node multiray electrode assembly comprises a proximal node including a multiray array with a plurality of spines connected at one end, each spine having at least one ablation electrode, and a distal node including a multiray array with a plurality of spines connected at one end, each spine having at least one diagnostic electrode, and wherein the dual node multiray electrode assembly has an expanded configuration and a collapsed configuration wherein the spines of the proximal multiray array are arranged generally along a longitudinal axis of the catheter body and the distal node conforms to the catheter body in the collapsed configuration, the elongated catheter body comprising an inner tubular member slidably disposed within a lumen of an outer tubular member, a proximal end of the inner tubular member being secured to a control handle, the proximal node multiray array being secured to a distal end of the outer tubular member and the distal node being secured to a distal end of the inner tubular member;
• positioning the distal end of the catheter at a desired region of the heart;
• deploying the distal mulitray array within a vessel in the expanded configuration to engage an inner diameter of the vessel;
• and
• positioning the proximal multiray array to bring at least one ablation electrode into contact with tissue forming an ostium of the vessel.