An intravascular renal neuromodulation catheter apparatus, comprising: an elongated tubular shaft defining at least one lumen, a therapeutic assembly disposed distally of the elongated shaft, the therapeutic assembly defining a central axis and having a distal portion and a proximal portion axially spaced along the central axis, the therapeutic assembly including- a plurality of energy delivery elements including at least a first energy delivery element and a second energy delivery element; and a helical support structure moveable between a delivery arrangement and a deployed arrangement, wherein the plurality of energy delivery elements are carried by the helical support structure; wherein a proximal region or portion of the support structure is coupled to and affixed to the elongated shaft; a control member operably coupled to the distal portion of the therapeutic assembly and disposed along the central axis such that the first and the second energy delivery elements are axially and radially spaced from one another about the control member by wrapping the support structure about the control member, wherein the distal end portion of the support structure is coupled to a collar element that includes a passage sized and shaped to slidably accommodate the control member that terminates at an end piece, wherein the control member comprises a control wire that extends from the elongated shaft and moves distally and proximally through the elongated shaft and the collar element, and wherein- distal movement of the control member relative to the elongated shaft places the therapeutic assembly in the delivery arrangement; and proximal movement of the control member relative to the elongated shaft places the therapeutic assembly in the deployed arrangement by causing the end piece to engage and proximally move the collar element. an elongated tubular shaft defining at least one lumen, a therapeutic assembly disposed distally of the elongated shaft, the therapeutic assembly defining a central axis and having a distal portion and a proximal portion axially spaced along the central axis, the therapeutic assembly including- a plurality of energy delivery elements including at least a first energy delivery element and a second energy delivery element; and a helical support structure moveable between a delivery arrangement and a deployed arrangement, wherein the plurality of energy delivery elements are carried by the helical support structure; wherein a proximal region or portion of the support structure is coupled to and affixed to the elongated shaft; a plurality of energy delivery elements including at least a first energy delivery element and a second energy delivery element; and a helical support structure moveable between a delivery arrangement and a deployed arrangement, wherein the plurality of energy delivery elements are carried by the helical support structure; wherein a proximal region or portion of the support structure is coupled to and affixed to the elongated shaft; a control member operably coupled to the distal portion of the therapeutic assembly and disposed along the central axis such that the first and the second energy delivery elements are axially and radially spaced from one another about the control member by wrapping the support structure about the control member, wherein the distal end portion of the support structure is coupled to a collar element that includes a passage sized and shaped to slidably accommodate the control member that terminates at an end piece, wherein the control member comprises a control wire that extends from the elongated shaft and moves distally and proximally through the elongated shaft and the collar element, and wherein- distal movement of the control member relative to the elongated shaft places the therapeutic assembly in the delivery arrangement; and proximal movement of the control member relative to the elongated shaft places the therapeutic assembly in the deployed arrangement by causing the end piece to engage and proximally move the collar element.