A surgical apparatus having an expandable structure including first, second and third spines forming a basket, movable between expanded and contracted positions. Each of the spines has first, second and third lumens, wherein an electrode element is movable within the first lumen of the first, second and third spines through a first opening in the spine. The second lumen of the first and second spines carries a temperature sensing element, the temperature sensing element exposed through a second opening in the spine positioned between the first and second lumens. The second lumen of the third spine is configured to receive a guidewire, and the third lumen of the first, second and third spines is connectable to a tube for carrying cooling fluid therethrough.