An energy delivery system (2000; 2200) for delivering electrical energy to tissue, the energy delivery system (2000; 2200) comprising: an elongate catheter member (2006; 2509; 2700) defining a longitudinal axis and dimensioned for passage within a body vessel, the catheter member (2006; 2509; 2700) defining a fluid lumen; and an expandable treatment member (2008; 2204; 2500) mounted to the catheter member (2006; 2509; 2700), the treatment member (2008; 2204; 2500) including an inflatable element (2036; 2206; 2300; 2400; 2506; 2704) in fluid communication with the fluid lumen, the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) adapted to transition between an initial condition and an at least partially expanded condition upon introduction of an anesthetic solution within the inflatable element (2036; 2206; 2300; 2400; 2506; 2704), the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) defining at least one aperture (2042; 2218; 2520; 2520; 2716) dimensioned to permit passage of the anesthetic solution from the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) to enter a wall of the body vessel to at least partially anesthetize nerve tissue therein, an electrode (2038; 2220; 2508; 2714) for delivering electrical energy to at least nerve tissue associated with the body vessel to cause at least partial denervation thereof, the electrode (2038; 2220; 2508; 2714) disposed along the inflatable element (2036; 2206; 2300; 2400; 2506; 2704), a source of an irrigation fluid, a source of the anesthetic solution, and characterised in that the system further comprises a valve in fluid communication with the source of the anesthetic solution, the source of the irrigation fluid, and the fluid lumen of the catheter member, wherein the valve is actuatable between an anesthetic mode to permit delivery of the anesthetic solution from the source of the anesthetic solution to the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) and an irrigation mode to permit delivery of the irrigation fluid from the source of the irrigation fluid to the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) for passage through the at least one aperture (2042; 2218; 2520; 2716) defined by the inflatable element (2036; 2206; 2300; 2400; 2506; 2704). an elongate catheter member (2006; 2509; 2700) defining a longitudinal axis and dimensioned for passage within a body vessel, the catheter member (2006; 2509; 2700) defining a fluid lumen; and an expandable treatment member (2008; 2204; 2500) mounted to the catheter member (2006; 2509; 2700), the treatment member (2008; 2204; 2500) including an inflatable element (2036; 2206; 2300; 2400; 2506; 2704) in fluid communication with the fluid lumen, the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) adapted to transition between an initial condition and an at least partially expanded condition upon introduction of an anesthetic solution within the inflatable element (2036; 2206; 2300; 2400; 2506; 2704), the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) defining at least one aperture (2042; 2218; 2520; 2520; 2716) dimensioned to permit passage of the anesthetic solution from the inflatable element (2036; 2206; 2300; 2400; 2506; 2704) to enter a wall of the body vessel to at least partially anesthetize nerve tissue therein, an electrode (2038; 2220; 2508; 2714) for delivering electrical energy to at least nerve tissue associated with the body vessel to cause at least partial denervation thereof, the electrode (2038; 2220; 2508; 2714) disposed along the inflatable element (2036; 2206; 2300; 2400; 2506; 2704), an electrode (2038; 2220; 2508; 2714) for delivering electrical energy to at least nerve tissue associated with the body vessel to cause at least partial denervation thereof, the electrode (2038; 2220; 2508; 2714) disposed along the inflatable element (2036; 2206; 2300; 2400; 2506; 2704), a source of an irrigation fluid, a source of the anesthetic solution, and