Dynamic Analysis of the Normal Tricuspid Annulus Using 3D Echocardiography

Purpose: Changes in the geometry of the normal tricuspid annulus (TA) throughout the cardiac cycle, as assessed by three-dimensional transthoracic echocardiography (3DTTE), have not been extensively described. The goal of this study was to characterize normal TA dynamics as a basis for a better understanding of tricuspid valve (TV) pathology. Methods:Westudied 98 subjects (45+15 years, range 19-80 years, BSA 1.81+0.22m2, 44 men) with normal TV who underwent 3DTTE full volume imaging of the right ventricle (RV) from the apical 4-chamber view (Philips, iE33 and GE Vivid E9) at 2 University Hospitals. All study subjects had a normal 2DTTE study, RV systolic pressure ≤35 mmHg and RV ejection fraction ¼ 55+7% (TomTec 4D RV software). Measurements were made (QLAB 9.0, Philips and EchoPAC BT 12, GE) of the TA area, antero-posterior (AP) and septal-lateral (SL) TA dimensions at the onset of systole (closure of the TV), endsystole (prior to TV opening), mid-systole (mid-point between onset and end-systole), early-diastole (initial TV leaflet opening) and late-diastole (TV opening after atrial contraction). Results:MeanTAareaanddimensions varied throughout the cardiac cycle (Table), being the largest in late-diastole and smallest at the onset of systole. TA fractional area change was38%.TAAPdimensionwaslarger than theSLdimension throughout the cardiac cycle (fig.A). Fractional changes in AP and SL dimensions were 23% and 18%, respectively. No significant differences were noted between genders (fig.B) or age groups. Conclusions:NormalTAis ahighly dynamicstructure andthis has important implications for its sizing. Customized software to characterize TA remodeling and dynamics throughout the entire cardiac cycle is needed for a better understanding of TV pathology.