These chest X rays show right ventricular enlargement, a dilated pulmonary trunk and increased pulmonary vascularity. In this PA view, right ventricular enlargement is suggested by the minimally elevated 
 cardiothoracic ratio   and the presence of an 
 upturned apex.  The 
 dilated pulmonary trunk 
		is manifested by the convex density below the aortic knob. There is also prominence of the 
 pulmonary arteries,  particularly well seen as dilatation of the right pulmonary artery. Such dilatation is compatible with increased blood flow, as seen with left-to-right shunts.
			
		
			
	
		In the lateral view with barium swallow, right ventricular enlargement is manifested by 
 obliteration of the retrosternal air space.  The pulmonary arteries are large.