QUANTITATION OF THE EFFECTIVE RIGHT-VENTRICULAR OUTPUT IN PATIENTS WITH PULMONARY ATRESIA AND INTACT VENTRICULAR SEPTUM AFTER PLACEMENT OF A RIGHT-VENTRICULAR OUTFLOW PATCH AND AN AORTOPULMONARY SHUNT

A mathematical derivation is presented of an equation that allows quan titation, in the cardiac catheterization laboratory, of the effective output of the right ventricle (Q(RV)) in patients with pulmonary atres ia and intact ventricular septum (PA/IVS) after palliation with a righ t ventricular outflow patch and an aorticopulmonary shunt. This deriva tion is based on the Fick principle and accounts for that portion of t he right-to-left atrial shunt that flows through the aorticopulmonary shunt to the lungs and thus contributes to the effective pulmonary blo od flow (Q(ep)). This equation relates Q(RV) to pulmonary blood flow ( Q(p)), systemic cardiac output (Q(s)), and Q(ep) by Q(RV) = Q(p) + Q(s ) - (Q(p))(Q(s))/Q(ep). By providing, pn assessment of right ventricul ar function, this equation may be helpful in determining the suitabili ty of the right ventricle to support biventricular repair. (C) 1994 Wi ley-Liss, Inc.