Gender and anthropometric parameters as determinants of echocardiographic and radiographic left atrial dimensions in normal subjects

Objectives: This study aimed to determine left atrial dimensions by echocardiography and frontal chest radiography in normal subjects.

Methods: 225 normal frontal chest radiographs (100 males and 125 females, aged 17–23 years) were analyzed. Left atrial size (LAS, cm) was assessed by measuring the distance from the midportion of the inferior wall of the left main bronchus to the lower margin of the “double density“ along or behind the right cardiac margin (C.E. Green et al, 1982). All the subjects underwent anthropometry and measurements of height, weight (from which body surface area, BSA, was calculated), upper arm (UAC) and leg (ULC) circumferences were taken. Subsequently echocardiography was performed on 147 of the subjects (73 males, 74 females) with Acuson Aspen (3.5MHz transducer) scanner using standard protocol. Statistica 6.0 (Stat Soft, USA) was used for statistical analysis.

Results: Radiographic LAS for all subjects, males and females measured 7.49±0.06, 9.78±0.16 and 7.13±0.06 respectively. Correlations were obtained with height (r=0.51, p<0.001), BSA (r=0.51, p<0.001), mass (r=0.45, p<0.01) and UAC (r=0.30, p<0.01). Echocardiographic anterior-posterior LA diameter in the left parasternal long axis view (cm) for all subjects, males and females are 3.08±0.03, 3.22±0.04 and 2.97±0.04 respectively. Correlations were obtained with UAC (r=0.56, p<00001), mass (r=0.53, p<0.00001), BSA (r=0.46, p<0.0001), ULC (r=0.33, p<0.001) and height (r=0.25, p<0.01). Though the radiographic and echocardiographic LA sizes are measured in different dimensions, the two methods correlate well (r=0.27, p<0.01).

Conclusions: Gender and anthropometric parameters influence both radiographic and echocardiographic LA dimensions.