In patients with an infarct-related ventricular septal defect, an intra-aortic balloon pump provides immediate and long-term hemodynamic improvement, resulting in an enhanced effective cardiac output and a reduced left-to-right-shunt and shunt flow ration. In patients who can be stabilized or remain stable, there is no habituation to the effects of the intra-aortic balloon pump; thus, later surgical closure of the ventricular septal defect might be possible in some patients.