Acute myocardial infarction symptoms masked by epidural morphine?

This report describes the case of an 80-year-old woman with a long history of chronic, stable angina pectoris who underwent resection of an abdominal aortic aneurysm and placement of an aortobifemoral bypass graft under a combination of epidural and general anesthesia. Epidural morphine was administered postoperatively for pain management. The patient suffered a massive myocardial infarction (MI) in the immediate postoperative period but experienced no chest pain or discomfort similar to her usual anginal symptoms. The use of epidural and spinal opioids in the treatment of anginal pain is reviewed and discussed in terms of the possibility that such epidural opioid therapy may have masked this patient's anginal symptoms.