[Coronary vasodilation during intracoronary injection of papaverine and acetylcholine in syndrome X: evaluation by coronary arteriograms and coronary venous oxygen saturation dynamics].

To evaluate coronary vasodilatory reserve in syndrome X, left coronary arteriography and continuous measurement of coronary venous oxygen saturation (CSO2-Sat) were performed during intracoronary injection of papaverine (PAP) and acetylcholine (ACh) in 11 patients of syndrome X and 13 control subjects. Coronary diameter after PAP increased 10.2% in the control group and 9.8% in the syndrome X group, but after ACh decreased 1.7% in the control group and decreased 2.3% in the syndrome X group. These changes in coronary diameter by PAP and ACh in the two groups were not significantly different. However, coronary vasodilatory responses estimated by CSO2-Sat dynamics to ACh and to ACh/PAP were significantly lower in the syndrome X group than those in the control group (p < 0.05), although coronary response to PAP in the 2 groups was not significantly different. These findings suggest that endothelial-dependent vasodilation of coronary microcirculation is decreased in syndrome X.