Devices, assemblies, systems, and techniques described herein may deliver a pressure wave to structures of a heart, such an aortic valve. For example, a medical assembly may include an expandable member configured to expand from a collapsed configuration to an expanded configuration, the expandable member configured to at least partially define a channel through the expandable member in the expanded configuration and one or more electrodes carried by the expandable member. The one or more electrodes may be configured to transmit an electrical signal through a fluid to cause the fluid to undergo cavitation that generates a pressure wave within the fluid.