Alternating pump gaps

A mechanical circulatory support system comprising:

• a ventricular assist device comprising a housing, an impeller, levitation magnets, a stator assembly, and control electronics, wherein the housing defines an inlet, a pump chamber, and an outlet, wherein the impeller is disposed and configured for magnetic suspension within the pump chamber, wherein the impeller comprises a first annular disk, a second annular disk, centrifugal impeller blades, first magnet segments, and second magnet segments, wherein the centrifugal impeller blades are disposed between the first annular disk and the second annular disk, wherein the first magnet segments are embedded in the first annular disk, wherein the second magnet segments are embedded in the second annular disk, wherein the stator assembly is disposed adjacent to the pump chamber so that the first annular disk is disposed between the stator assembly and the centrifugal impeller blades, wherein the stator assembly comprises stator coils operable to generate a stator magnetic field that interacts with the first magnet segments to rotate the impeller within the pump chamber and apply a first positioning force to the impeller, wherein the levitation magnets are disposed adjacent to the pump chamber so that the second annular disk is disposed between the levitation magnets and the centrifugal impeller blades so that the levitation magnets apply a second positioning force to the impeller, and wherein the control electronics are disposed within the housing and configured to control currents supplied to the stator coils to generate the stator magnetic field to control rotation of the impeller within the pump chamber and to control a magnitude of the first positioning force applied to the impeller to control an axial position of the impeller in the pump chamber;
• a percutaneous cable connected to the ventricular assist device;
• an external control unit connected to the ventricular assist device via the percutaneous cable;
• and
• an external power source connected to the external control unit.