Single coronary artery from the right sinus of valsalva: an unusual variant of a rare condition.

An 83-year-old woman presenting with collapse was found to have an impaired left ventricular ejection fraction (20% predicted). Conventional coronary angiography and magnetic resonance imaging (MRI) were both unable to define the coronary artery anatomy. MRI revealed no previous myocardial infarction or fibrosis. A computed tomographic (CT) coronary angiogram was performed, revealing a single coronary artery (SCA) arising from the right coronary sinus. This vessel quadrifurcated into (i) a normal dominant right coronary artery supplying the posterior circulation, (ii) an anomalous left anterior descending (LAD) artery passing …