• Abnormal origin
    • Absent left main stem (dual LCX and LAD origin)
    • High origin
  • Origin from an improper sinus
    • RCA from left anterior sinus
    • LAD from right anterior sinus
    • LCX from right anterior sinus
    • Left mainstem from right anterior sinus
    • Single coronary artery
  • Origin from other structure
    • Anomalous left coronary artery from the pulmonary artery (ALCAPA)
  • Congenital absence or aneurysm
    • Stenosis, atresia, hypoplasia
    • Ectasia or aneurysm
  • Abnormal number
    • Absent coronary artery
    • Duplicated coronary artery
  • Abnormal termination
    • Fistula with cardiac chamber, pulmonary artery, pulmonary vein, systemic circulation