diagnosed in utero with an ultrasound after 18 weeks gestation. However, many cases of simple l-TGA are "accidentally" diagnosed in adulthood, during diagnosis or treatment of other conditions. Treatment Simple l-TGA has a very good prognosis, with many individuals being asymptomatic and not requiring surgical correction. In a number of cases, the (technically challenging) "double switch operation" has been successfully performed to restore the normal blood flow through the ventricles. References External links Congenital heart defects Aortic balloon valvuloplasty in corrected transposition of the great arteries