We compared @-dimensional and Doppler echocardiographic indices of RV size and function , neo-aortic and tricuspid valve annulus dimensions and function , and aortic size and patency at @ @ months and @ @ months in subjects randomized to a Norwood procedure using either the modified Blalock-Taussig shunt ( MBTS ) or right ventricle to pulmonary artery shunt ( RVPAS ) .