For that reason, babies with l-TGA usually won't have any obvious symptoms at birth.

正这个原因，患有L-TGA的宝宝在出生时没有明显的症状。

So transposition of the great arteries, or TGA —you might be able to guess— is when these two arteries swap locations.

所大动脉转位（TGA），顾名思义，就指这两个动脉交换了位置。

Ultimately the cause of TGA is unknown, but there are diseases and behaviors that are associated with higher risk of babies having TGA.

TGA的病因目前未知，但有很多疾病和行为婴幼儿患TGA的高危因素。

So in this case, unlike d-TGA, circulation is preserved and therefore sometimes this is called congenitally corrected TGA.

所不像d-TGA，在这种情况下，正常的循环被保留了下来，因此有时候又被称为正的TGA。

This essentially means that d-TGA leads to death unless there is some way for blood between the pulmonary and systemic circulations to mix.

这就意味着，除非有一种方法可将肺循环和全身循环的血混合，否则d-TGA会导致死亡。

If the shunt is large enough such that the initial symptoms aren't noticed and the TGA isn't repaired, the heart can progress to congestive heart failure.

如果分流足够大使得最初症状没被发现且TGA没有修复，就会发展为充血性心力衰竭。

Less commonly, babies can have levo-transposition of the great arteries, or l-TGA, with levo meaning that the aorta's primarily to the " left" of the pulmonary artery.

更少见地，宝宝可能会有左旋-大动脉转位，即L-TGA，左旋的意思主动脉主要位于肺动脉的左侧。

This isn't good, and this situation is actually called complete TGA, or sometimes dextro-TGA or d-TGA, dextro meaning " right" , since in this case, the aorta's in front of and primarily to the right of the pulmonary artery.

这种情况不太妙，被称为完全TGA，有时也叫右旋TGA或者d-TGA，dextro的意思右旋的，因为这种情况下，主动脉在肺动脉的前面并且主要在肺动脉的右边。