Author contributions:
Toshitaka Nakaya created the PV loop shown in Figure 1. Junichi Nakamura
recorded the RV pressure during the catheterization using a
micromanometry. Yasuyuki Chiba and Hiroyuki Iwano recorded the 3D image,
analyzed the data, and created the 3D movie clip. Ichizo Tsujino
conceptualized the study and reviewed the manuscript.