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Mechanisms of myocardial ischemia in a patient with left main coronary artery atresia.

This report describes the different clinical and instrumental manifestations of coronary ischemia in a patient with left main coronary artery atresia. Exercise test and thallium-201 perfusion scintigraphy during isometric exercise test were negative for angina and electrocardiographic changes. Conversely, dipyridamole infusion caused severe angina, marked ST-segment changes and diffuse thallium-201 uptake abnormalities. This peculiar anatomical condition offers the opportunity of high-lighting the role played by the microcirculation in determining myocardial ischemia.