The invention is a device, system, and method for repairing heart valve function, which may include bisecting native valve leaflets for improved deployment of a prosthetic heart valve in the native valve annulus. The invention may include a catheter having a cutting element shaft with a cutting element configured to puncture a valve leaflet and/or make a controlled cut through the leaflet. The device may have an extendable foot configured to be positioned on an opposite side of the valve leaflet from the cutting element shaft. The device may include magnets to guide the cutting element and/or cutting element shaft in proper alignment with the extendable foot and to hold the elements in place during leaflet bisection.