Relation Between Stress - Induced Myocardial Perfusion Defects on Cardiovascular Magnetic Resonance and Coronary Microvascular Dysfunction in Patients With Cardiac Syndrome

reversible myocardial perfusion defects during stress myocardial scintigraphy (2,3) and, even more, by the evidence of an impaired response to vasodilator stimuli of coronary blood flow and/or resistance, assessed with several different methods (4-10). In particular, a blunted increase in subendocardial flow in response to intravenous administration of adenosine (11) was shown by cardiovascular magnetic resonance (CMR), a high-resolution technique that allows the assessment of transmural myocardial perfusion homogeneity with gadolinium as contrast medium (12). Yet, the ischemic origin of CSX remains still debated (13), mainly because of the usual lack-during stress tests-of regional myocardial wall motion abnormalities, The purpose of this study was to investigate whether a direct relation can be demonstrated between myocardial perfusion defects detected during dobutamine stress test (DST) by cardiovascular magnetic resonance (CMR) and impairment of coronary microvascular dilatory function in patients with cardiac syndrome X (CSX).