[Determination of the size of the right atrium using two-dimensional echocardiography].

Echocardiographical and functional parameters of the right ventricle have been established. In addition, to improve the analysis of right heart dynamics, normal values for right atrial dimensions and the tricuspid valve anulus diameter are required. We therefore examined 30 normal adult subjects, 15 males (aged 31 +/- 10 years, mean +/- SD) and 15 females (aged 28 +/- 8 years) using two-dimensional echocardiography in the apical 4-chamber view. The contour of the right atrium was delineated with a light pen, and the end-diastolic and end-systolic areas were calculated using a computerized integration method; the percentage area shortening fraction was determined as end-systolic area - end-diastolic area/end-systolic area. The diameter of the tricuspid anulus was measured in the ECG-triggered two-dimensional stop frame; the greatest diameter was reached immediately after the end of the P-wave in the ECG and the smallest diameter at midsystole. Thus it was possible to calculate the anulus shortening fraction as greatest diameter - shortest diameter/greatest diameter. For determination of the circumference of the tricuspid valve anulus a circular geometry was assumed. The mean values, the standard deviation and the 95% upper confidence bound for the 90th percentile were calculated. The end-diastolic right atrial area in the apical 4-chamber view was 3.0 +/- 0.8 cm2/m2 in the whole study group (males 3.4 +/- 1.8 cm2/m2 and females 2.6 +/- 0.5 cm2/m2) and the end-systolic area was 6.9 +/- 1.0 cm2/m2 (males 7.1 +/- 1.1 cm2/m2 and females 6.6 +/- 0.9 cm2/m2); the calculated value of the area shortening fraction was 56.7 +/- 9.7%.(ABSTRACT TRUNCATED AT 250 WORDS)