Geometric changes of tricuspid valve, particularly leaflets configuration, in functional tricuspid regurgitation (TR) remain to be defined. We sought to investigate geometric changes of tricuspid valve tenting in functional TR secondary to pulmonary hypertension by transthoracic real-time 3-dimensional echocardiography (3DE). Real-time 3DE was performed in 30 individuals (17 patients with TR and 13 control subjects). We used a novel software system with 3DE to reconstruct tricuspid geometry at midsystole. In patients with TR, tricuspid leaflets were tethered into right ventricle with apparent tenting showing a mountain-like bulging. Maximum tenting site was mostly located at the center of the tenting. Tenting volume was larger (4.2 +/- 2.4 vs 1.1 +/- 0.6 cm(3), P < .001), and the maximum and mean tenting lengths were longer, than in control subjects. Annular area was also larger (11.3 +/- 2.3 vs 8.7 +/- 1.8 cm(2), P = .003) than in control subjects. Geometric changes in functional TR secondary to pulmonary hypertension were characterized by enlargement of tricuspid tenting volume and dilatation of annulus. This study suggested usefulness of the novel system with 3DE in evaluation of tricuspid valve geometry.