A medical device (10, 110, 210) comprising: a housing (20, 120, 220) including at least one inlet for receiving blood flow, and at least one outlet for delivering blood flow, the housing having a longitudinal axis; a fluid barrier (35, 135) disposed within the housing and separating the housing into a first section (21, 121, 221) containing the at least one inlet and the at least one outlet, and a second section (22, 122, 223), the fluid barrier being impervious to fluid; an impeller (60, 160, 360) disposed within the first section of the housing, wherein a longitudinal axis of the impeller and the longitudinal axis of the housing are the same, the impeller having a main body and at least one blade extending radially outward from the main body; at least a first magnet (40, 140, 240) coupled to an impeller shaft (50, 150, 350), the impeller shaft coupled to the impeller, the first magnet disposed in the first section of the housing and rotatably coupled to the impeller shaft; a drive shaft (90, 190, 290) disposed within the second section of the housing; and at least a second magnet (42, 142, 242) disposed on the drive shaft within the second section of the housing, the first and second magnets configured and arranged such that rotation of the second magnet causes the first magnet to rotate; characterized in that the first magnet has a first opening (143, 243) therethrough configured for receiving and coupling the impeller shaft to the first magnet, the second magnet has a second opening (143,243) therethrough configured for receiving and coupling the drive shaft to the second magnet, wherein the first and second openings each have a first transverse cross-sectional shape (144,244) taken perpendicular to a longitudinal axis of the drive shaft; and in that the drive shaft and at least a portion of the impeller shaft each have a second transverse cross-sectional shape (158, 166, 191) taken perpendicular to the longitudinal axis of the respective shafts, wherein the first and second transverse cross-sectional shapes are non-round, such that rotation of the impeller shaft and drive shaft causes rotation of the first and second magnets, respectively. a housing (20, 120, 220) including at least one inlet for receiving blood flow, and at least one outlet for delivering blood flow, the housing having a longitudinal axis; a fluid barrier (35, 135) disposed within the housing and separating the housing into a first section (21, 121, 221) containing the at least one inlet and the at least one outlet, and a second section (22, 122, 223), the fluid barrier being impervious to fluid; an impeller (60, 160, 360) disposed within the first section of the housing, wherein a longitudinal axis of the impeller and the longitudinal axis of the housing are the same, the impeller having a main body and at least one blade extending radially outward from the main body; at least a first magnet (40, 140, 240) coupled to an impeller shaft (50, 150, 350), the impeller shaft coupled to the impeller, the first magnet disposed in the first section of the housing and rotatably coupled to the impeller shaft; a drive shaft (90, 190, 290) disposed within the second section of the housing; and at least a second magnet (42, 142, 242) disposed on the drive shaft within the second section of the housing, the first and second magnets configured and arranged such that rotation of the second magnet causes the first magnet to rotate; characterized in that the first magnet has a first opening (143, 243) therethrough configured for receiving and coupling the impeller shaft to the first magnet, the second magnet has a second opening (143,243) therethrough configured for receiving and coupling the drive shaft to the second magnet, wherein the first and second openings each have a first transverse cross-sectional shape (144,244) taken perpendicular to a longitudinal axis of the drive shaft; and in that the drive shaft and at least a portion of the impeller shaft each have a second transverse cross-sectional shape (158, 166, 191) taken perpendicular to the longitudinal axis of the respective shafts, wherein the first and second transverse cross-sectional shapes are non-round, such that rotation of the impeller shaft and drive shaft causes rotation of the first and second magnets, respectively.