A catheter for diagnosing and ablating tissue is disclosed that has astabilizedspine electrode assembly. The stabilized spine electrode assembly has at leasttwospines secured to the catheter body at their proximal ends and at least onetether,secured between locations distal of the proximal ends of adjacent spines. Thespineshave a collapsed arrangement in which the spines are arranged generally alongalongitudinal axis of the catheter body and an expanded arrangement in which atleast aportion of each spine bows radially outwards from the longitudinal axis andthe at leastone tether exerts tension on the adjacent spines.
