A cardiac pump includes a plain bearing assembly having a first plain bearing portion that is coupled to a cardiac pump rotor and a second lain bearing portion that is coupled to a cardiac pump housing. The plain bearing assembly is configured to rotatably support the cardiac pump rotor within the cardiac pump housing in at least an axial direction of the cardiac pump rotor. A magnetic bearing assembly includes a first magnetic bearing portion that is coupled to the cardiac pump rotor and a second magnetic bearing portion that is coupled to the cardiac pump housing. The magnetic bearing assembly is configured to rotatably support the cardiac pump rotor within the cardiac pump housing in a radial direction of the cardiac pump rotor and bias the cardiac pump rotor in the axial direction such that the magnetic bearing assembly provides a preload force to preload the plain bearing assembly.