1. A catheter for treatment of a human patient via renal denervation, the catheter apparatus comprising: a handle assembly; a tubular elongate shaft extending from a distal end to a proximal end slidably disposed within the handle assembly; an elongate control member slidably disposed within the tubular elongate shaft and having— a proximal end protruding from the elongate shaft proximal end and fixedly attached within the handle assembly; and a distal region protruding from the elongate shaft distal end and extending along a central axis; and a helical support structure having— a plurality of energy delivery elements carried thereon including at least a first energy delivery element and a second energy delivery element axially and radially spaced from one another about the control member; a delivery state and a deployed state; a proximal end coupled to the elongate shaft distal end; and an elongate form wrapped about the control member distal region; and a distal end coupled to the control member distal region such that the support structure distal end remains at a fixed distance from the handle assembly; wherein— proximal movement of the elongate shaft relative to the control member places the helical support structure in the delivery state; and distal movement of the elongate shaft relative to the control member places the helical support structure in the deployed state.