ABNORMAL CARDIAC PAIN PERCEPTION IN SYNDROME-X

Objectives. The purpose of this study was to determine whether a dimin ished cardiac pain threshold contributes to chest pain in patients wit h syndrome X. Background. There have been some reports of an altered p ain perception in syndrome X. Methods. Intracardiac catheter manipulat ion was performed in four groups of patients (syndrome X [group 1, 36 patients]; mitral valve disease and normal coronary arteries [group 2, 36 patients]; mitral valve disease and coronary artery disease [group 3, 36 patients]; and heart transplant recipients with normal coronary arteries [group 4, 36 patients]). Coronary flow velocity was measured in patients with syndrome X and in transplant recipients by use of an intracoronary Doppler catheter positioned in the left anterior descen ding coronary artery at intracardiac catheter manipulation. Coronary f low reserve in response to papaverine was also measured in patients wi th syndrome X and in transplant recipients. Results. Intracardiac stim ulation produced typical anginal chest pain in 34 group 1 (syndrome X) patients (94%). However, chest pain was produced only in five patient s (14%) in group 2, seven patients (19%) in group 3 and no patients in group 4. There were no significant changes in coronary blood flow vel ocity associated with chest pain in group 1 patients. Coronary flow re serve in response to a hyperemic dose of intracoronary papaverine was significantly lower in the syndrome X group. There was no significant difference in the prevalence with which the stimu- lation tests produc ed chest pain in patients with syndrome X with an impaired coronary fl ow reserve or a positive radionuclide scan. Conclusions. The results o f our study suggest that abnormal cardiac pain perception is a fundame ntal abnormality in syndrome X.