An apparatus for vascular denervation, comprising a catheter configured for delivery into a vessel of a patient. A balloon is mounted on a distal tip of the catheter, the balloon being configured to be inflatable and further configured so that, upon inflation, the balloon adopts a shape that includes a first edge and a second edge that wind around each other in a double helix, the first edge and the second edge being separated from each other by a first crease and a second crease that also wind around each other in a double helix. A first electrode is attached to the balloon and is located to extend along the first edge.