The development of a percutaneously insertable catheter pump for temporary left ventricular and circulatory support in patients with acute ischemic cardiomyopathy.The expandable axial flow pump (introduction diameter 9-F, expanded diameter 6.5 mm) is mounted at the tip of a catheter, designed to be placed in aortic transvalvular position. Hydrodynamic tests were performed in a static flow model and in a pulsatile mock circuit (Medos VAD, Stolberg, Germany). Cardiogenic shock was simulating in vitro and in vivo.At a rotation speed of 32,000 rpm the catheter pump delivered a maximum flow of more than 4.0 L/min against a systemic mean pressure of 60 mmHg. Under shock simulation the pump significantly improved output and systemic pressure.A percutaneously insertable catheter pump is technically feasible. Hydrodynamic efficacy allows sufficient cardiac support under simulated shock condition.