A heart assist device comprising a rotary pump housing having a cylindrical bore,a pumping chamber and a motor stator including an electrically conductive coillocated within the housing and surrounding a portion of the cylindrical bore.A rotor has a cylindrical shaft, at least one impeller appended to one end of theshaft, and a plurality of magnets located within the shaft. The rotor shaft ispositioned within the housing bore with the magnets opposite the motor stator,and the impeller is positioned within the pumping chamber. The housing bore isclosely fitted to the outer surface of the shaft forming a hydrodynamic journalbearing, with the pumping chamber and journal bearing connected by a leak pathof blood flow between the pumping chamber and the journal bearing. A backironof the motor stator attracts the rotor magnets to resist longitudinal displacementof the rotor within the housing during operation. The relative orientation ofpositions of the inflow, outflow, and leakage flow paths may be varied withinthe pump, such as to accommodate different intended methods for implantationand/or use.
