REPORT OF A PATIENT WITH SYNDROME-X DUE TO EXCESSIVE ADENOSINE EFFECT- MYOCARDIAL MIGRAINE WITHOUT MYOCARDIAL-ISCHEMIA

A 53-year-old female presented with disabling chest pain. The pain had most of the characteristics of ischemic pain; however, the results of the initial clinical investigation were consistent with the diagnosis of syndrome X. That is, her treadmill exercise test was positive but her coronary angiogram was normal A dipyridamole-thalium; test resulte d in severe chest pain, marked ST abnormalities, but no evidence of an y focal reduction in flow. A dipyridamole stress echocardiogram reveal ed that left ventricular function was entirely normal during the dipyr idamole-induced pain and ST segment abnormalities, making ischemia an unlikely cause and for either. To attempt to account for this paradox, the hypothesis was generated that both the pain and ST segment abnorm alities were due to a primary abnormality of adenosine metabolism rath er than secondary to ischemia. Accordingly, adenosine-MIBI scans were done with and without pretreatment with aminophylline Infusion adenosi ne virtually immediately resulted in crushing chest pain and profound ST abnormalities again without any evidence of focal abnormalities of MIBI estimated flow. By contrast, administration of adenosine after pr etreatment with aminophylline failed to produce either chest pain or S T abnormalities. Moreover, long term therapy with aminophylline almost entirely relieved the symptoms which had been so distressing. This ca se indicates that there is a subset of patients with syndrome X - in w hich faults in adenosine metabolism result in excessive adenosine accu mulation or effect and this results,; in turn, in adenosine-induced is chemic-like chest pain and adenosine-induced ST abnormalities. There i s, however, no actual ischemia of the myocardium. Given the known effe cts of adenosine on coronary flow, the problem in this subset of patie nts appears to be equivalent to an attack of myocardial migraine and b lockers of adenosine action might be of help to other patients with a similar pathophysiology for their chest pain.