Clinical manifestations of myocardial stunning

The phenomenon of myocardial stunning has been observed in all animal speci es studied. The possible occurrence of myocardial stunning in man has been demonstrated after either regional ischemia (such as exercise-induced angin a, vasospastic or unstable angina) or after global ischemia (i.e., after ca rdioplegic arrest during cardiac surgery, or cardiac arrest, or heart trans plantation). Finally, it may also be observed in patients with acute myocar dial infarction, subjected to recanalization therapy, because viable myocar dium, salvaged by reperfusion, may remain stunned, with delayed contractile recovery. Occurrence of stunning may aggravate hemodynamic conditions in already unst able patients, and it may lead to underestimation of the extent of myocardi um salvaged by thrombolysis. Repeated episodes of stunning may lead to a co ndition of apparently 'chronic' contractile dysfunction that may be difficu lt to differentiate from hibernation, because of the technical difficulties in accurately measuring myocardial blood flow in patients, and because bot h phenomena may coexist and overlap in the same patient. In addition, recen t evidence suggests that repeated episodes of stunning may lead to a progre ssive worsening of the residual contractile dysfunction and to longer recov ery times, and it has thus been suggested, and it is much debated, that hib ernation might at least in part be the consequence of repetitive episodes o f stunning. Coron Artery Dis 12:357-361 (C) 2001 Lippincott Williams & Wilk ins.