CHARACTERIZATION OF HIBERNATING AND STUNNED MYOCARDIUM

Both the hibernating and the stunned myocardium are characterized by r eversible contractile dysfunction. In hibernating myocardium ischaemia is still ongoing, whereas in stunned myocardium blood flow is fully o r almost fully restored.Both the hibernating and the stunned myocardiu m retain an inotropic reserve. In hibernating myocardium the increase in contractile function is at the expense of metabolic recovery wherea s in stunned myocardium no metabolic deterioration occurs during inotr opic stimulation. Therefore. inotropic stimulation in combination with metabolic imaging may help not only to identify viable, dysfunctional myocardium bur also to distinguish between hibernating and stunned my ocardium. The therapy of hibernating myocardium is to restore blood ho w to the hypogerfused tissue, Myocardial stunning per se requires no t herapy at all, since by definition blood flow is normal and contractil e function will recover spontaneously. If, however, myocardial stunnin g is severe, involves large parts of the left ventricle and thus impai rs global left ventricular function, it can be reversed with inotropic agents and procedures. In the experimental setting, antioxidant agent s, calcium antagonists and ACE inhibitors attenuate stunning, most eff ectively when administered before ischaemia.