An apparatus includes a balloon adapted to be placed adjacent a calcified region of a body. The balloon is inflatable with a liquid. The apparatus further includes a shock wave generator within the balloon that produces shock waves that propagate through the liquid for impinging upon the calcified region adjacent the balloon. The shock wave generator includes a plurality of shock wave sources distributed within the balloon.

An electrode assembly for a shock wave apparatus. An electrode assembly (30) is disposed inside a balloon (10) of a shock wave apparatus (100). The electrode assembly (30) comprises: a first electrode (301); an insulating layer (302), the first electrode (301) being disposed inside the insulating layer (302) and the tail end of the first electrode (301) being exposed from the tail end of the insulating layer (302); a first electrical conductor (303), the first electrical conductor (303) being disposed on at least a portion of the outer peripheral surface of the tail end of the insulating layer (302); and a second electrode (304), the second electrode (304) being disposed on at least a portion of the outer peripheral surface of a base end of the insulating layer (302), such that an insulating gap is provided between the second electrode (304) and the first electrical conductor (303).