Calcium and stunned myocardium.

Calcium administration during ischemia or at the onset of reperfusion is generally considered to be deleterious because cytosolic calcium is elevated at this time. In contrast, the administration of calcium antagonists before or during ischemia is protective. While calcium antagonists may not be beneficial when given after reperfusion, calcium administration during this period has been found to enhance the recovery of systolic and diastolic function of stunned myocardium.