Measurement of PAS
First, in the parasternal short axis window, we obtained the pulmonary artery. Thereafter, the pulmonary blood flow Doppler recordings were measured under the semilunar pulmonic valve. The MFS (maximum frequency shift) of the pulmonary flow was recorded for at least 5 succeeding beats. The PfAT, which is described as the distance between the starting of systolic pulmonary artery flow and peak flow rate, was measured for at least 5 succeeding beats. The PAS value was then obtained by dividing average MFS by average PfAT (Fig. 1 ). Intra- and inter-observer agreements were 0.97 and 0.93 for PAS measurements, respectively (p < 0.001).