Aspects of the disclosure relate to devices and methods for preparing an existing, implanted prosthetic aortic valve for subsequent prosthetic aortic valve implantation. To prepare the existing valve, a valve preparation device is delivered to the valve and valve leaflets are severed either via mechanical cutting or electrodes so that the leaflets cannot obstruct a blood flow path once a prosthetic valve is subsequently implanted within the valve. Similarly, in alternate embodiments, devices and methods of the disclosure can be used for preparing a native aortic valve for delivery and implantation of a prosthetic valve.