An angioplasty catheter for increasing the patency of a body vessel by altering an obstruction in the body vessel includes an elongate shaft having a proximal end and a distal end. At least one electrical conductor is disposed at the distal end and movable from a low profile position to a high profile position in proximity to the obstruction. A non-distensible balloon disposed between the conductor and the shaft is inflatable from the proximal end of the shaft to move the conductor between the low profile position and the high profile position. In the high profile position the conductor can be electrosurgically energized to ablate the obstruction and thereby increase the patency of the body vessel. The conductor may include a circuit which is printed on the exterior surface of the balloon. An overlying insulation layer can be provided with a slot to limit the exposure of the conductor to the obstruction thereby increasing the current density in the electrosurgical procedure.