Described here are devices and methods for forming shock waves. The devices may comprise an axially extending elongate member. A first electrode pair may comprise a first electrode and a second electrode. The first electrode pair may be provided on the elongate member and positioned within a conductive fluid. A controller may be coupled to the first electrode pair. The controller may be configured to deliver a series of individual pulses to the first electrode pair, where each pulse creates a shock wave. The controller may cause current to flow through the electrode pair in a first direction for some of the pulses in the series and in a second direction opposite the first direction for the remaining pulses in the series.

A retrieval catheter and methods of use are described for removing a heart valve therapy such as a leaflet clip or artificial leaflet cord. The retrieval catheter can include a cutting element and a basket, piercing element, clamping mechanism, or similar grasping device. The method includes delivering a catheter to the region of the heart valve therapy and then manipulating the catheter and associated instruments to cut tissue as necessary and then remove the heart valve therapy and withdraw the catheter.

Procedures may be performed on the heart after the installation of a mitral valve fixation device. In order to prepare the heart for such procedures, the fixation device may be removed or disabled in minimally invasive ways (e.g., through an endovascular procedure), without requiring open access to the heart. The fixation device may be partitioned so that one portion may remain attached to each leaflet of the mitral valve. In another example, the leaflets may be cut along the edges of the distal element(s) of the fixation device, so as to cut the fixation device from the leaflet(s). Systems and devices for performing such procedures endovascularly are disclosed. Fixation devices with improved access to a release harness are also disclosed.