Table 2.

Evidence against Microvascular Coronary Dysfunction (CMD) in Cardiac Syndrome X

Authors and Year	Assessment Method	Key Findings
Panza JA, Laurienzo JM, Curiel RV, et al. (1997).44	Dobutamine mediated dilatation	- Like normal controls, CSX patients showed a quantitatively normal myocardial contractile response without development of wall motion abnormalities in response to dobutamine.44
Rosano GM, Kaski JC, Arie S, et al. (1996).45	Blood pH and lactate levels during right atrial pacing	- Patients with coronary artery disease showed a greater fall of coronary sinus pH, oxygen saturation, and lactate extraction ratio compared to CSX patients (p<0.01, p<0.05, and p<0.01 respectively).45
Rosen SD, Uren NG, Kaski JC, et al. (1994).46	Dipyridamole mediated dilatation	- Myocardial blood flow in CSX patients and control subjects at rest was 1.05 and 1.00 respectively and after dipyridamole administration was 2.73 and 3.00 respectively (p=NS).46
Camici PG, Gistri R, Lorenzoni R, et al. (1992).41	Dipyridamole mediated dilatation	- Among patients with chest pain and angiographically normal coronary arteries, 1/3 had reduced coronary vasodilatory reserve post-dipyridamole administration. 12/14 patients with reduced reserve had exercise ST segment depression but 16/29 patients with normal reserve also had ST depression suggesting the role of factors other than reduced coronary reserve and ischemia in the genesis of ST depression.41
Camici PG, Marraccini P, Lorenzoni R, et al. (1991).42	Analysis of metabolites during rapid atrial pacing	- No net lactate release in patients with CSX during atrial pacing - CSX patients carried out the same external work with a smaller increase in blood flow, oxygen consumption, and energy expenditure than normal controls - During atrial pacing, CSX patients continued to rely on fatty acid substrates for oxidative metabolism.42
Nihoyannopoulo s P, Kaski JC, Crake T, et al. (1991).43	Stress two- dimensional echocardiogram during right atrial pacing	- In patients with CSX, no regional wall motion abnormalities seen on two-dimensional imaging of any myocardial segment. - Percent systolic wall thickening increased over values at rest in each myocardial segment during right atrial pacing.43

Data from Refs 41-46.