Passage of the catheter system through the tricuspid valve as visualized by echocardiography. The passage of the catheter system through the tricuspid valve and entering the right ventricle was visualized in aortic short axis view by echocardiography. The green arrows indicate the position of the catheter system. AO, aorta; PA, pulmonary artery; RA, right atrium; RV, right ventricle.