Assessment of left atrial mechanical function by two-dimensional echocardiography in hypertensive patients.

The left atrium (LA) have an important role in the normal functioning of the heart thanks to its three functions: reservoir, conduct and pump. Several pathologies lead directly or indirectly to morphological and functional modifications of the LA. Investigate the effect of arterial hypertension on LA size and function. Prospective study including 50 hypertensive patients compared to 50 healthy controls. LA Volumes were measured using transthoracic echocardiography by biplane Simpson method at different times of cardiac cycle: at the end of systole (maximum LA volume (Vmax)), at mitral valve closure (minimum LA volume (Vmin)) and immediately before LA contraction (Vp)). LA reservoir function (total emptying volume and expansion index), conduct function (passive emptying volume and passive emptying fraction) and pumping function (active emptying volume and active emptying fraction) have been calculated. Hypertension was associated with an increase of all LA volumes: Vmax (p<0.001), Vmin (p=0.001) and Vp (p<0.001). LA reservoir function evaluated by LA total emptying volume was higher in hypertensives than in control group (p=0.032). LA conduct function was impaired in hypertensive patients with a significantly lower passive emptying fraction in hypertensive group compared to control group (22 ± 12% versus 32 ± 11%, p <0.001, respectively). This decrease was greater in the presence of left ventricular hypertrophy (p = 0.02). LA pumping function was significantly higher in hypertensive patients than in controls with an increase of LA active emptying fraction (35±12% versus 30±12%respectively; p=0.037). The increase of LA pumping function was found to be higher in hypertensive patients with impaired diastolic function (p=0.029). Hypertension was associated with an increase of pumping and reservoir functions and a decrease in left atrial passive emptying function. These changes appear to be related to left ventricular hypertrophy and the degree of left ventricular diastolic dysfunction.