Catheter with multiple spines of different lengths arranged in one or more distal assemblies

A catheter, comprising:

• an elongated catheter body;
• and
• a distal assembly distal of the elongated catheter body and comprising at least four spines, each of the at least four spines having a proximal end fixedly attached to a distal end of the elongated catheter body and a free distal end,
• wherein each of the at least four spines comprises:
• a support arm having shape memory;
• a non-conductive covering in surrounding relation to the support arm;
• and
• at least one electrode;
• wherein the at least four spines are arranged in a radial pattern about a longitudinal axis of the distal assembly and a length of each of the at least four spines increases in radial progression about the longitudinal axis, and when the distal assembly is in an expanded arrangement, each of the at least four spines extends radially outward from the catheter body.