ThecircumeferentialmappingcatheterinFigure1.56isinapulmonaryvein.TheLAOprojectionclearlyshowsthattheveinisaleft-sidedpulmonaryvein.Thecircumferentialmappingcatheterislikelylocatedatwhichsite?
Leftupperpulmonaryvein
Leftlowerpulmonaryvein
Theleftatriumnotengagingthepulmonaryvein
Cannotbedetermined
Answer:D-Cannotbedetermined.
图1.56中白箭头所示环状标测导管位于某一根肺静脉内。LAO影像清楚显示该肺静脉为左侧肺静脉。问题：环状标测导管可能位于哪个部位？
A.左上肺静脉
B.左下肺静脉
C.左房内，并未插入肺静脉
D.不能确定
答案：D——不能确定。
Attimes,theupperandlowerleft-sidedveinsarisefairlyclosetoeachother.ThefactthatintheRAOprojectionthecatheterislocatedfairlyposterior