Right to left (reverse) shunts
These are rare. The most common cause is Tetralogy of Fallot (PS, a high VSD,
dextro-positioned and overriding aorta and right ventricular hypertrophy).
With either a right ventricular or non-selective injection, the left ventricle
and aorta are seen to fill (without prior filling of the left atrium) concurrently
with the right ventricle and pulmonary artery.
A jet of contrast agent may be seen across the shunt.
Reverse shunting may occur with a septal defect or a PDA in which pulmonary hypertension
develops; in such circumstances the right ventricular pressure exceeds the left
and the shunt reverses.
Premature filling of the left side will be seen and the pulmonary arteries may
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