Fig. 34.1
Diagrammatic representation of transposition of the great arteries. Note that the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle. If there are no communications between the left and right side of the heart, it would be impossible to supply oxygenated blood to the body which is incompatible with life
Technically, double outlet right ventricle (DORV) cannot be classified as TGA because in TGA both great arteries must arise from the wrong side of the ventricular septum. However, DORV with a subpulmonary ventricular septal defect results in transposition physiology and is repaired in a manner similar to d-TGA.
34.3 Clinical Presentation
A newborn with d-TGA represents a medical emergency. It is critical to establish or exclude this diagnosis and to document and to insure adequate sites for mixing between the systemic and pulmonary circuits which, in d-TGA, are in parallel rather than in series.
34.4 Physical Examination
The primary physical finding is cyanosis. The right ventricular impulse will be increased. Depending upon the associated defects, there may or may not be a murmur. If a VSD or pulmonary stenosis is present, there will be a systolic murmur. If there is associated coarctation of the aorta, the femoral pulses will be weak or absent.
34.5 Echocardiographic and Cardiac Catheterization Issues
The diagnosis of d-TGA and most associated malformations can be established noninvasively with two-dimensional echocardiography. The presence of a patent ductus arteriosus can be determined, but the ductus arteriosus cannot be relied on as a stable source of mixing because it likely will close. The ductus arteriosus can be maintained patent by infusion of prostaglandin E-l, and this should be done if the baby is extremely hypoxemic (PaO2 < 25 mmHg), is acidotic, or is to be transferred to another institution.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
