LEFT ATRIAL CONTRACTILITY FUNCTION IN ART ERIAL-HYPERTENSION

The purpose of this study was the assessment of the left systolic atri al function (LSAF) in 43 hypertensive subjects (HS) with left Ventricu lar hypertrophy (LVH). (LV mass index) (LVMI) (> 134 g/m(2) for men, 1 10 g/m(2) for women) and in 32 normal subjects (NS). The both groups w ere matched for age, body surface, heart rate and LV fractional shorte ning. Left atrial volume (LAV) was calculated by the formula : LAV = 8 A(1) x A(2)/3 pi 1 in which A(1) is the area of the four-chamber view , A(2) is the area of the two-chamber view and L is common length in t he two views. The atrial function contractility was evaluated by the f ollowing parameters: 1. LA stroke volume (LASV) = LAV - LAMV where LAV is the volume before atrial systole and LAMV is the LA minimal volume . 2, LA ejection fraction (LAEF) = LASV/LAV. 3. Atrial ejection force (AEF) = peak A/MOA in which peak A wave is the maximal late diastolic velocity and MOA is the mitral orifice area. 4. Atrial transport (AT) = A/M in which M area is under the mitral velocity curve and A-area un der the late diastolic velocity curved assessed by Doppler echo. [GRAP HICS] Thus ail above parameters are significantly increased in HS. In HS, LASV is correlated to LAV (r = 0.84 :p < 0.001) and to LVMI (r = 0 .32;p < 0.05). LAEF is correlated to peak A (r = 0.90;p < 0.001) and L VMI (r = 0.34; p < 0.05). Conclusions, In HS with LVH in comparison wi th N, the increase of the LA contractility is considered to be urged b y the increase of LAV (Frank-Starling's law). These data could be expl ained by the less distensibility of LV chamber in relation to LVH.