A blood circulation assist system, comprising: an implantable blood pump; a first external controller; a first driveline connected to the first external controller and through which electrical power is transmittable via the first external controller to the implantable blood pump; a first driveline contact assembly electrically connected to the first driveline; a second external controller; a second driveline connected to the second external controller and through which electrical power is transmittable via the second external controller to the implantable blood pump; a second driveline contact assembly electrically connected to the second driveline; a distal driveline through which electrical power is transmitted to the implantable blood pump; and a distal driveline contact assembly electrically connected to the distal driveline, the distal driveline contact assembly being electrically connectable to: either of the first driveline contact assembly and the second driveline contact assembly; and either of the first driveline contact assembly and the second driveline contact assembly while being connected to the other of the first driveline contact assembly and the second driveline contact assembly; characterized in that while the first driveline contact assembly is connected to the distal driveline contact assembly, the first driveline contact assembly is rotatable relative to the distal driveline contact assembly between a retention orientation for the first driveline contact assembly and a connection orientation for the first driveline contact assembly; wherein while the first driveline contact assembly is connected to the distal driveline contact assembly and in the retention orientation for the first driveline contact assembly, the first driveline contact assembly is engaged with the distal driveline contact assembly to maintain connection of the first driveline contact assembly with the distal driveline contact assembly; and while the first driveline contact assembly is in the connection orientation for the first driveline contact assembly, the first driveline contact assembly can be connected to the distal driveline contact assembly and disconnected from the distal driveline contact assembly. an implantable blood pump; a first external controller; a first driveline connected to the first external controller and through which electrical power is transmittable via the first external controller to the implantable blood pump; a first driveline contact assembly electrically connected to the first driveline; a second external controller; a second driveline connected to the second external controller and through which electrical power is transmittable via the second external controller to the implantable blood pump; a second driveline contact assembly electrically connected to the second driveline; a distal driveline through which electrical power is transmitted to the implantable blood pump; and a distal driveline contact assembly electrically connected to the distal driveline, the distal driveline contact assembly being electrically connectable to: either of the first driveline contact assembly and the second driveline contact assembly; and either of the first driveline contact assembly and the second driveline contact assembly while being connected to the other of the first driveline contact assembly and the second driveline contact assembly; either of the first driveline contact assembly and the second driveline contact assembly; and either of the first driveline contact assembly and the second driveline contact assembly while being connected to the other of the first driveline contact assembly and the second driveline contact assembly; characterized in that while the first driveline contact assembly is connected to the distal driveline contact assembly, the first driveline contact assembly is rotatable relative to the distal driveline contact assembly between a retention orientation for the first driveline contact assembly and a connection orientation for the first driveline contact assembly; wherein while the first driveline contact assembly is connected to the distal driveline contact assembly and in the retention orientation for the first driveline contact assembly, the first driveline contact assembly is engaged with the distal driveline contact assembly to maintain connection of the first driveline contact assembly with the distal driveline contact assembly; and while the first driveline contact assembly is in the connection orientation for the first driveline contact assembly, the first driveline contact assembly can be connected to the distal driveline contact assembly and disconnected from the distal driveline contact assembly.