Eighty patients with cardiogenic shock secondary to myocardial infarction were treated with the intra-aortic balloon pump (IABP). The initial response to pumping was good, with resolution of shock in 80%. Sixty-eight patients did not tolerate subsequent withdrawal from IABP and were termed balloon-dependent. Selective coronary and left ventricular cineangiography in 52 balloon-dependent patients identified 30 possible surgical candidates. Operative procedures in 24 produced 9 survivors (37%). Persistent dependence upon mechanical circulatory assistance after myocardial infarction may not indicate massive ventricular infarction. Early angiography after initial hemodynamic improvement on IABP is an essential step in the identification of those patients with persistent, reversible ischemia in whom emergency surgery may be indicated.