transposition of the great arteries (tga) vsd ps
the great arteries are reversed in their connection to the ventricles, but in addition there is a ventricular septal defect and the pulmonary valve is stenosed or partially obstructed. the infant will present with cyanosis. enlarging the atrial communication by balloon atrial septostomy may be necessary to ensure mixing. if pulmonary stenosis is severe, shunt placement may be necessary. this type of patient will eventually have a rastelli repair, where the aorta is connected to the left ventricle, the vsd closed and a conduit placed between the right ventricle and the pulmonary artery. this is usually delayed for a few years to avoid several conduit replacements with growth.
the great arteries will arise in parallel orientation, with the aorta from the right and the pulmonary artery from the left ventricles respectively. the aortic valve is usually anterior and to the right of the pulmonary artery. the pulmonary valve will be thickened and doming and the pulmonary artery will be smaller in size than the aorta. there will be turbulent accelerated flow across the pulmonary valve. the associated ventricular septal defect can be of variable size and in any site in the septum although perimembranous is the most common site.
this echocardiographic picture may be mistaken for double outlet right ventricle with pulmonary stenosis but the difference is not of much practical importance. care must be taken to ensure that the ventricles are not inverted as parallel great arteries, with disproportion of the arterial sizes, can be a presentation of corrected transposition with pulmonary stenosis. in complete transposition, the posterior, left-sided ventricle should be less trabeculated at the apex than the anterior right ventricle, which contains the moderator band. in addition, the tricuspid valve in the anterior right ventricle is situated more apically than the mitral valve in the posterior left ventricle (the normal off-setting of the av valves).
parallel origin of the great arteries, aorta from right, pulmonary artery from left ventricles (no ‘cross-over’).
thickened, doming pulmonary valve.
pulmonary artery smaller than aorta.
- asplenia (ivemark)
- digeorge syndrome
- maternal diabetes
- maternal epilepsy- untreated
- retinoic acid embryopathy (accutane embryopathy)
- short rib-polydactyly syndrome non-majewski type
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kirklin jw, colvin ev, mcconnell me, bargeron lm jr complete transposition of the great arteries: treatment in the current era pediatric clinics of north america 37:171-7