Intravascular lithotripsy

A medical device, comprising:

• an elongated body;
• a balloon positioned at a distal portion of the elongated body, the balloon configured to receive a fluid to inflate such that an exterior surface of the balloon contacts an interior surface of a target treatment site within a vasculature of a patient;
• and
• one or more pressure-wave emitters positioned along a central longitudinal axis of the elongated body within the balloon, the one or more pressure-wave emitters configured to propagate pressure waves radially outward through the fluid to fragment a calcified lesion at the target treatment site,
• wherein at least one of the one or more pressure-wave emitters comprises an electronic emitter comprising a first electrode and a second electrode,
• wherein the first electrode and the second electrode are arranged to define a spark gap between the first electrode and the second electrode,
• wherein the first electrode extends radially inward through the elongated body and at least partially inward into an inner lumen of the elongated body, and
• wherein the second electrode comprises a portion of a hypotube.