English: What is transposition of the great arteries? The great arteries are the aorta and the pulmonary artery, and transposition means to switch places, so with transposition of the great arteries (TGA), the aorta and pulmonary artery switch places such that they're connected to the wrong ventricle. This video covers two forms of TGA—dextro-TGA and levo-TGA, as well as the pathophysiology behind each. It also covers the important clinical signs and symptoms.