Three-dimensional tricuspid annular function provides insight into the mechanisms of tricuspid valve regurgitation in classic hypoplastic left heart syndrome.

BACKGROUND: Tricuspid regurgitation (TR) has a negative impact on outcome in hypoplastic left heart syndrome (HLHS). There is a paucity of data assessing the mechanisms of TR. Lateral forces from the left ventricle play an important role in normal tricuspid valve (TV) function. This study evaluates the role of real-time 3-dimensional echocardiography in the assessment of the TV annulus and subvalvular apparatus in HLHS.
METHODS: In all, 31 real-time 3-dimensional echocardiographic studies from 26 patients (1 day-17 years old) with classic HLHS were included. In all, 7 studies were before and 8 were after first-stage palliation; 8 were postcavopulmonary shunt and 8 were post-Fontan. Only patients with severe left ventricular attenuation were included. Studies were subdivided into two groups: mild TR (N = 20) and severe TR (STR) (N = 11). Data from 17 control subjects were used for comparison. TV annular area, bending angle (saddle shape), and position of anterior papillary muscle were analyzed.
RESULTS: All annular segments moved in equally during systole in mild TR, whereas septal-lateral diameter contraction was significantly diminished in STR. TV annular area was larger in HLHS (mild TR, 1265 +/- 325; STR, 1767 +/- 450 mm2/m2) than in control subjects (762 +/- 85) (P < .001). However, area change was reduced only in STR (12.4 +/- 4.6% vs control subjects 20.4 +/- 8.3%, P < .05). Annular shape was flat during systole in HLHS. Anterior papillary muscle was laterally displaced in STR.
CONCLUSIONS: TV annular dynamics were different in patients with HLHS as a result of lack of interaction form left ventricle. Annular function, especially in septal-lateral direction, was further impaired in STR.