Increased coronary vasoconstrictor response to acetylcholine in women with chest pain and normal coronary arteriograms (cardiac syndrome X).
Cardiac syndrome X (CSX) is characterized by exercise-induced angina, positive exercise stress-test responses and angiographically normal coronary arteries. The condition characteristically affects more women than men and is often associated with coronary microvascular dysfunction, i.e., abnormal vasodilatory responses. Recent clinical observations suggest that increased coronary vasoconstriction may have a pathogenic role in CSX. We therefore sought to assess the prevalence of increased epicardial and microvascular coronary vasoconstriction in women with CSX. Among 1,120 consecutive women with angina undergoing diagnostic coronary angiography 39 fulfilled criteria for CSX (mean age 63 ± 9 years) and were included in the study (27 also complained about rest angina). Five women without angina (mean age 64 ± 24 years) and normal coronary arteriograms served as controls. Patients and controls underwent intracoronary acetylcholine testing with a standardized protocol. Severe (≥75 % diameter reduction) epicardial constriction developed in 12 CSX patients (31 %) with reproduction of their angina in 10. All 12 patients showed diffuse epicardial constriction affecting mainly the distal coronary segments. Twenty-two CSX patients (56 %) experienced their usual angina without epicardial constriction of which 21 had ischemic ECG shifts. The remaining five CSX patients (13 %) had no angina or constriction in response to acetylcholine. None of the control patients had angina or constriction during ACH testing. Increased epicardial as well as microvascular coronary constriction in response to acetylcholine are frequent findings in women with CSX. The results indicate that inappropriate coronary constriction is likely to contribute to the anginal symptoms of these patients. The ACH-test may be useful in the clinical setting to unmask this vasomotor disorder.