Tricuspid annular (TA) size and function play important roles in planning the need for associated TA annuloplasty in patients undergoing cardiac surgery for left-sided heart valve diseases. However, TA diameter normative values and the extent of TA dynamic changes during cardiac cycle remain to be established.

This was a prospective, cross-sectional study of 219 healthy volunteers (mean age, 43 ± 15 years; 57% women), using conventional two-dimensional transthoracic echocardiographic (2DE) imaging to assess the variability of TA diameter measurement in relation to 2DE view and timing during cardiac cycle. TA diameter was obtained from apical right ventricular (RV)–focused four-chamber, parasternal long-axis RV inflow, and parasternal short-axis at aortic plane 2DE views at five time points during the cardiac cycle. Right atrial and RV volumes were measured using three-dimensional echocardiography.

TA diameters differed significantly among the three 2DE views and changed significantly during the cardiac cycle in all views. Moreover, mean fractional shortening of TA diameter was 24 ± 6% in the four-chamber view, 20 ± 7% in the parasternal long-axis RV inflow view, and 29 ± 11% in the parasternal short-axis at aortic plane view. One multivariate linear regression analysis, age, gender, and right atrial and RV volumes were independently correlated with TA diameters and accounted for 55% of the variance of midsystolic TA diameter in the four-chamber view.

This study provides references values for TA diameters and dynamics using 2DE imaging. Age, gender, and right chamber sizes, as well as the 2DE view and time during the cardiac cycle, significantly influenced TA diameters in healthy individuals. These data may help better identify TA dilatation using 2DE imaging for surgical planning.