Plasma levels of endogenous opioid peptides in patients with acute myocardial infarction.

There is substantial evidence that cardiac opioid receptors are activated during arrhythmias induced by administration of opioid peptides or myocardial ischemia, supporting the hypothesis that endogenous opioid peptides (EOP) are involved in myocardial infarction. This prospective clinical trial is designed to determine whether the ischemia-induced arrhythmias and extent of the infarct are related to the release of the EOP beta-endorphin in patients with acute myocardial infarction. Two groups were included in the study, patients with acute myocardial infarction, and healthy volunteers who served as controls. The results indicate that, compared to the controls, there was augmentation of ischemic arrhythmias and ischemic damage as assessed by serum creatine kinase activity, accompanied by an elevated level of beta-endorphin, in patients with acute myocardial infarction. The above data strongly indicate that EOP are indeed involved in the pathophysiology of myocardial infarction, and suggest these peptides have an important role in ischemic heart disease.