Fig. 1

Recording of pulmonary annular motion velocity and measurement of pulmonary arterial capacitance. A representative recording of pulmonary annular motion evaluated by tissue Doppler imaging in a healthy 2-year-old boy is shown. The long-axis view of the right ventricular outflow tract and main pulmonary artery (PA) is visualized, and the sample volume is positioned on the RV free wall side of the pulmonary annulus, as indicated by the yellow arrow (a). Pulmonary annular velocity of the RV free wall side is determined (b). The tricuspid annular motion waveform from the same individual is also evaluated for the sake of comparison (c). The tissue Doppler-derived annular velocity waveform comprises s1′, s2′, e’, and a’ for the pulmonary annulus, and s’, e’, and a’ for the tricuspid annulus. Simultaneous recordings of pulmonary annular motion and RV and PA pressure curves in a 4-year-old girl with a ventricular septal defect (VSD) are shown (d). The measurements of systolic pulmonary arterial capacitance (sPAC) and diastolic pulmonary arterial capacitance (dPAC) are shown (e). The calculations to obtain sPAC and dPAC are described in the methods section. The comparison between sPAC and dPAC is shown in panel f. Boxes show the distribution (25th and 75th percentiles; central line, median). Vertical lines represent the range between the 5th and 95th percentiles. The relationship between sPAC and dPAC is shown in panel g. Ao, aorta; PA, pulmonary artery; RV, right ventricle; ICT, isovolumic contraction time; IRT, isovolumic relaxation time; sPAC, systolic pulmonary arterial capacitance; dPAC, diastolic pulmonary arterial capacitance; SPAP, systolic pulmonary arterial pressure; DPAP, diastolic pulmonary arterial pressure; PAPP, pulmonary arterial pulse pressure