The Effects of Arterial and Pulmonary Shunts on the Dynamics of Aortic Coarctation

This communication deals with the manner in which collateral arterial channels and a persistent ductus arteriosus affect the dynamics of an uncomplicated aortic coarctation which was studied experimentally by means of artificial shunts and registration of pressure pulses. The conclusion is reached that effective collaterals or a surgical subclavian-aortic shunt can be effective dynamically in reducing hypertension and left ventricular strain and in providing an adequate flow through tissues despite the fact that the femoral pressure pulse does not revert to a normal form. The presence of an aortic-pulmonary shunt affects aortic pressure both through reduction in aortic resistance and augmentation of systolic discharge until very severe degrees of coarctation exist. The right ventricle of the normal heart can function as a systemic ventricle only when the aorta is almost completely occluded.