In a normal heart, the sequence of blood is from
vena cava to right ventricle, then to the lungs and finally from lungs to the left ventricle to be circulated throughout the body. In patients with transposition, the order is from cava to left atrium and ventricle, then to the lungs and finally to the right side of the heart to be pumped out to systemic circulation. The Mustard Procedure allows total correction of transposition of the great vessels. It creates a baffle to redirect deoxygenated caval blood to the left atrium, which then pumps blood to the left ventricle, which in turn delivers this deoxygenated blood to the lungs. The effect is that the left ventricle is a functional right, and the right ventricle a functional left. ==Superseded by Arterial Switch==