The left atrium (LA) is a complex anatomical structure. Transesophageal echocardiography (TOE) is the gold standard of first-line imaging for studying it. We therefore proposed to perform an echocardiographic study of the LA, in both two-dimensional and three-dimensional modes, in a heterogeneous patient population.

This is a descriptive, retrospective study including 70 patients who underwent TOE regardless of indication in the echocardiography laboratory of the cardiology department of Mongi Slim Hospital.

The valvular heart disease and the endocarditis were the two major indications for TOE in our series. Half of the patients had atrial fibrillation and half were in sinus rhythm. The largest average of the diameters of the ostium measured for in a two-dimensional study was found at 135° while the lowest average was found at 45°. The 135° incidence also allowed visualization of maximum lobes. In three-dimensional mode, the means of the maximum and minimum ostium’ diameters were respectively 19.09±5.42 and 15.27±4.55 millimeters. The majority of the LA had an ostium that was oval or ellipsoid. The mean telediastolic and tele systolic volumes were respectively 3.83±3.79 and 1.95±2.86 milliliters. The mean ejection fraction was 53.31%±18.39. The mean area of the ostium measured in three-dimensional mode and calculated in two-dimensional mode was respectively 2.99±2.03 and 1.98±1.03cm²; P=0.001. It was found that the LA in the shape of “Cactus” had the most important dimensions however, it had the lowest ejection fraction. In addition, the highest ejection fraction was found in the “Chicken wing” form. The mean fill and drain flows were respectively 50.07cm/s±20.67 and 56cm/s±30.81. These flows were altered if atrial fibrillation.

The three-dimensional TOE of LA has made an important contribution to understanding this complex structure.