A rare case of ectopic origin of the left anterior descending artery from the right coronary sinus misdiagnosed as a chronic total occlusion lesion.

We report a rare case of a left anterior descending artery originating from the right coronary sinus. The original left anterior descending artery was small and appeared occluded; it was initially misdiagnosed as a chronic total occlusion lesion. However, a displaced left anterior descending artery was identified during angiographic evaluation. Although a left main coronary artery arising from the right coronary sinus is uncommon (prevalence of 0.03%), to the best of our knowledge, this is the first reported case of an ectopic left anterior descending artery originating from the right coronary sinus.