Basket catheter with mushroom shape distal tip

A method for fabricating a medical probe, comprising:

• providing an insertion tube configured for insertion into a body cavity of a patient;
• connecting a proximal end of a basket assembly to a distal end of the insertion tube, the basket assembly comprising a plurality of resilient spines, which are configured to bow radially outward from an axis of the basket assembly and are conjoined at a distal end of the basket assembly;
• providing an axial electrode attached to the plurality of resilient spines and disposed at the distal end of the basket assembly, the axial electrode configured to contact tissue in the body cavity and comprising:
• a circular shape with a rounded surface;
• a diameter of at least 1.5 millimeters;
• a thickness of at least 20% of the diameter;
• and
• sides having a radius of curvature of at least 25% and at most 50% of the thickness;
• and
• providing a plurality of radial electrodes disposed on the plurality of resilient spines which are configured to contact the tissue in the body cavity.

A method for treatment, comprising:

• inserting, into a body cavity, an insertion tube having a distal end containing a lumen passing through the insertion tube;
• deploying, into the body cavity from the distal end, a basket assembly having a proximal end that is connected distally to the insertion tube and comprising a plurality of resilient spines, which are configured to bow radially outward from an axis of the basket assembly and are conjoined at a distal end of the basket assembly, the basket assembly comprising:
• an axial electrode attached to the plurality of resilient spines and disposed at the distal end of the basket assembly, the axial electrode configured to contact tissue in the body cavity and comprising:
• a circular shape with a rounded surface;
• a diameter of at least 1.5 millimeters;
• a thickness of at least 20% of the diameter;
• and
• sides having a radius of curvature of at least 25% and at most 50% of the thickness, and
• a plurality of radial electrodes disposed on the plurality of resilient spines which are configured to contact the tissue in the body;
• positioning the basket assembly so that the axial electrode presses against the tissue in the body cavity;
• and
• conveying, via the axial electrode, ablation energy to the tissue.