Reperfusion injury. A possible link between catecholamine-induced and ischemic myocardial alterations.

In this study we have compared myocardial lesions induced by catecholamines and coronary occlusion and reperfusion injuries in rats. Although microcirculatory factors were found to play an important role in catecholamine-induced cardiac muscle cell injury, alterations in sarcolemmal membrane permeability suggest a direct cardiotoxic effect. Cardiac muscle cells damaged irreversibly by ischemia reveal sarcomeres in extreme relaxation and mitochondria with floccular densities; cardiac muscle cells that die following reperfusion exhibit contraction band formation and mitochondria with calcium phosphate deposits. The ultrastructural appearance of reperfused ischemic cardiac muscle cells was similar to that observed following administration of catecholamines. These morphological similarities suggest a common causal pathway for stress-induced and ischemic heart diseases.