Figure 3. Frequency domain analyses.

Solid lines show the least squares means and the ribbon shows their SE. Moduli ($|Z|$) is shown in the top row whereas the bottom row shows the phase (ϕ). Results are shown for the baseline (A) (n = 18 animals), volume (B) (n = 6), dobutamine (C) (n = 8) and AMI (D) (n = 8) phases. Pulmonary input impedance (Z _T) is shown in black and longitudinal impedance of the pulmonary vessels (Z _L) is shown in blue, whereas the harmonic spectra impedance of the periodical time‐varying system of the LH ($Z_{\mathrm{LH}}^{\ast }$) is shown in red. Note that, for most harmonics, Z _T is below Z _L, demonstrating a favourable effect of the harmonic response of the LH on Z _T. [Color figure can be viewed at wileyonlinelibrary.com]