Methods and devices for transvascular prosthetic chordae tendinea implantation are disclosed. A catheter is advanced into the left atrium, through the mitral valve, and into the left ventricle. A ventricular anchor is deployed from the catheter and into a wall of the left ventricle, leaving a ventricular suture attached to the ventricular anchor and extending proximally through the catheter. A leaflet anchor is deployed to secure a mitral valve leaflet to a leaflet suture, with the leaflet suture extending proximally through the catheter. The leaflet suture is secured to the ventricular suture to limit a range of travel of the leaflet in the direction of the left atrium. Also disclosed is an assembled in situ mitral valve leaflet restraint, having a neo papillary muscle and a neo chordae tendinea.