The Haemodynamics of the Abnormal Outflow Tract

Abstract

I have been asked to speak on this subject of the haemodynamics of the abnormal right ventricular outflow tract. It may be stenotic, regurgitant, or atretic. If the obstruction cannot be relieved by excision alone, bypass it with a valved conduit. That is how simple the pioneering work of Mr. D. Ross and others (Ross and Somerville, 1966; McGoon, Rastelli and Ongley, 1968, McGoon, Rastelli and Wallace, 1970; Ionescu, Macartney and Wooler, 1972; Doty et al., 1972; Bowman, Hancock and Malm, 1973) has made the practical haemodynamics of the abnormal right ventricular outflow tract. But, as so often happens, clearing away one problem reveals others, more subtle and previously unsuspected. The most startling of these problems is one which,I suspect, anybody involved on any scale with the surgery of tetralogy of Fallot, with or without pulmonary atresia, has met and been baffled by: the patient who goes for surgery with a low or normal pulmonary artery pressure and comes back from the operating theatre (if he is lucky) with a pulmonary artery pressure approaching or exceeding systemic and a normal,left atrial and pulmonary venous pressure (Somerville, et al., 1974).