Stunned Myocardium:

Prolonged dysfunction of the myocardium after a brief episode of severe ischemia, with gradual return of contractile activity. It occurs frequently, both in the experimental laboratory and in clinical medicine. Since stunned myocardium occurs adjacent to necrotic tissue after prolonged coronary occlusion, many myocardial infarcts may be a mixture of necrotic and stunned tissue. (Braunwald, Heart Disease, 1992, p1176)