[Spasm in a single coronary artery]

A 52 year old man presented with effort and resting angina with positive exercise stress testing and myocardial scintigraphy. The initial coronary angiogram showed a single coronary vessel arising from the right coronary ostium dividing into a right coronary artery with a normal trajectory lined with a few non stenotic atheromatous plaques and a left coronary artery which passed between the aorta and pulmonary artery to reach the left atrioventricular groove. At first, it was suggested that the angina was due to compression of the left coronary vessel by the great arteries during effort, but this mechanism could not explain attacks of resting angina and the failure of betablocker therapy. An ergometrine test performed during repeat coronary angiography induced almost complete occlusion of the right coronary vessel and Prinzmetal diaphragmatic ischaemia. The anginal attacks were completely suppressed by Calcium antagonist drugs. The association of coronary spasm and a single coronary artery is rare; only one case has been previously reported. We do not believe that there was a relationship between the two phenomena in our case: the spasm occurred at a distance from the aberrant course of the vessel. The authors emphasise the diagnostic problems and the potential danger of this association.