Purpose: Left atrial size may increase in hypertension, diastolic dysfunction, atrial fibrillation, valvular disease, ischemic heart disease and heart failure. Accurate measurement of left atrial size is mandatory for the diagnosis and management of heart diseases. Recently, left atrial volume has been recommended for the routine measurement of the left atrial size. These measurements are complex and sometimes controversial. We attempted to define when left atrial volume measurement may not be necessary.
Methods: 100 echocardiographic examinations were selected according to left atrial size and/ or left atrial area. 25 patients were included into each of 4 groups with: severely, moderately, mildy dilated and normal left atrium respectively, according to routine 2-dimesional echocardiographic measurements - area and antero-posterior diameter of the left atrium. Then left atrial volume adjusted to the body weight was calculated for each of these examinations and left atrium was re-sized.
Results: Initial diagnosis of normal left atrial size and severely dilated left atrium were accurate in 100% of evaluated studies according to left atrial diameter and area: all the patients with normal left atrial area and diameter had normal left atrial volume index. Patients with severe left atrial dilatation had severely increased left atrial volume. In patients with mild and moderate left atrial dilatation left atrial size was usually underestimated. Left atrial volume calculation is necessary when left atrial diameter is 3.9 – 4.6 cm in women and 4.1 – 5.2 cm in men and/or area is 20-40 cm² independent of sex.
Conclusions: If left atrium is normal or severely dilated according to simple measurements of antero-posterior diameter and area, further calculation of left atrial volume index may not be necessary. In all other cases left atrial volume index should be calculated.
