▁pul mon ary ▁ar ter ies , ▁with ▁pres ervation ▁of ▁two ▁normal ▁sem il un ar ▁val ves . ▁It ▁is ▁the ▁result ▁of ▁an ▁incomplete ▁separation ▁of ▁the ▁a ort ic op ul mon ary ▁tr unk ▁that ▁normally ▁occurs ▁in ▁early ▁f etal ▁development ▁with ▁formation ▁of ▁the ▁spir al ▁sept um . ▁A ort op ul mon ary ▁sept al ▁defect s ▁occur ▁in ▁isol ation ▁in ▁about ▁half ▁of ▁cases , ▁the ▁remainder ▁are ▁associated ▁with ▁more ▁complex ▁heart ▁ab normal ities . ▁ ▁C aus es ▁ ▁Di agn osis ▁ ▁Sub types ▁ ▁There ▁are ▁numerous ▁types , ▁differenti ated ▁by ▁the ▁extent ▁of ▁the ▁defect . ▁These ▁types ▁are : ▁▁▁▁▁ ▁Type ▁I : ▁simple ▁defect s ▁leading ▁to ▁communication ▁between ▁the ▁asc ending ▁a ort a ▁and ▁pul mon ic ▁tr unk ▁ ▁Type ▁II : ▁defect s ▁that ▁extend ▁to ▁the ▁origin ▁of ▁the ▁right ▁pul mon ary ▁ar tery ▁▁ ▁Type ▁III : ▁anom alous ▁origin ▁of ▁the ▁right ▁pul mon ary ▁ar tery ▁from ▁the ▁asc ending ▁a ort a ▁ ▁It ▁is ▁also ▁class ified ▁as ▁simple ▁or ▁complex . ▁Simple ▁defect s ▁are ▁those ▁that ▁do ▁not ▁require ▁surg ical ▁repair , ▁occur ▁with ▁no ▁other ▁defect s , ▁or ▁those ▁that ▁require ▁minor ▁str ight - forward ▁repair ▁( duct us ▁ar ter ios us , ▁at rial ▁sept al ▁defect ). ▁Complex ▁defect s ▁are ▁those ▁that ▁occur ▁with ▁other ▁an atom ical ▁anom al ies ▁or