A 51-year-old man was referred to coronary angiography because of a non ST-elevation acute coronary syndrome. The coronary angiography showed a rare single coronary artery arising from the right anterior sinus of Valsalva. This artery was responsible for the entire vascularisation of the heart. The left coronary artery arises from the posterior atrioventricular right coronary artery (RCA). Stenoses of the large posterior atrioventricular coronary artery of the RCA and the first segment of the left anterior descending artery were detected and determined the clinical status (panels A, B and C below; also, supplementary movies I and II are available online at http://heart.bmj.com/supplemental). Drug-eluting stent implantations were performed both with good clinical and angiographic results (panels D, E and F below; supplementary movie III available online).

Subsequently, an enhanced 16-multislice spiral computed tomography (MSCT) confirmed the absence of a coronary artery from the left anterior sinus (panel G), detailed the anatomic findings (panels H, I and J) and confirmed the success of stenting both lesions (panels K and L) (panels G–L are in the supplementary figure available online at http://heart.bmj.com/supplemental).

To the best of our knowledge, this is the first description of a whole left coronary artery arising from the posterior atrioventricular coronary artery of the RCA. We also assessed the interest of MSCT in such a situation, because conventional exercise tests often produce conflicting results in patients with coronary anomalies alone or in combination with an obstructive coronary disease. Comprehensive MSCT examinations may thus be useful in understanding the anatomy of abnormal coronary artery and in controlling the result of uncommon angioplasties as a non-invasive reference test for the follow-up to detect in-stent restenosis.

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Figure 1 Coronary angiography and multislice spiral computed tomography. The coronary angiography showed (A) a stenosis of the posterior atrioventricular artery (arrow), (B) a stenosis of the left anterior descending artery (arrow) and (C) an overview of both stenoses (arrows). The coronary angiography showed the result after stent implantation on (D) the posterior atrioventricular artery (arrow), (E) the left anterior descending artery (arrow) and (F) the final result after the implantation of both stents (arrows). RCA, right coronary artery; LAD, left anterior descending artery. (Further details and the supplementary figure are available at http://heart.bmj.com/supplemental)