A heart pump and a catheter assembly therefor are provided that include a flexible catheter body having a proximal end and a distal end, the catheter body having a plurality of lumens therethrough. The catheter body can be sufficiently flexible to extend from a peripheral access to a patient's heart. The catheter assembly can also include an impeller assembly having an impeller and a housing. The impeller assembly can be coupled with the flexible catheter body such that a tensile force applied to opposite ends of the catheter assembly enhances the security of the connection between the catheter body and the impeller assembly.
