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[Left atrial contractility function in hypertension]
1Service de cardiologie, centre hospitalier et universitaire, Tirana, Albanie.
Insights
Hypertensive individuals with left ventricular hypertrophy show increased left atrial contractility, likely due to reduced left ventricular chamber distensibility. This highlights the impact of hypertension on atrial function.
Area of Science:
- Cardiology
- Echocardiography
- Cardiac Physiology
Background:
- Hypertension is a leading cause of cardiovascular disease.
- Left ventricular hypertrophy (LVH) is a common complication of hypertension.
- Left atrial function plays a crucial role in overall cardiac performance.
Purpose of the Study:
- To assess left systolic atrial function (LSAF) in hypertensive subjects (HS) with LVH.
- To compare LSAF parameters between HS with LVH and normal subjects (NS).
- To investigate correlations between LSAF parameters and left ventricular mass index (LVMI).
Main Methods:
- Echocardiographic assessment of left atrial volume (LAV) and derived parameters.
- Calculation of left atrial stroke volume (LASV), LA ejection fraction (LAEF), atrial ejection force (AEF), and atrial transport (AT).
- Matching of HS and NS for age, body surface area, heart rate, and LV fractional shortening.
Main Results:
- All evaluated atrial function parameters were significantly increased in HS with LVH compared to NS.
- LASV showed a significant correlation with LAV (r = 0.84; p < 0.001) and LVMI (r = 0.32; p < 0.05).
- LAEF was correlated with peak A wave velocity (r = 0.90; p < 0.001) and LVMI (r = 0.34; p < 0.05).
Conclusions:
- Hypertensive subjects with LVH exhibit increased left atrial contractility compared to normal subjects.
- The enhanced atrial contractility is likely driven by increased left atrial volume, consistent with Frank-Starling's law.
- Reduced left ventricular chamber distensibility, secondary to LVH, may contribute to the observed changes in atrial function.
Unlabelled:
The purpose of this study was the assessment of the left systolic atrial function (LSAF) in 45 hypertensive subjects (HS) with left ventricular hypertrophy (LVH). (LV mass index) (LVMI) (> 134 g/m2 for men, > 110 g/m2 for women) and in 32 normal subjects (NS). The both groups were matched for age, body surface, heart rate and LV fractional shortening. Left atrial volume (LAV) was calculated by the formula: LAV = 8 A1 x A2/3 pi l in which A1 is the area of the four-chamber view, A2 is the area of the two-chamber view and L is common length in the two views. The atrial function contractility was evaluated by the following 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 under the late diastolic velocity curved assessed by Doppler echo. [table: see text] Thus all 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 LVMI (r = 0.34; p < 0.05).
Conclusions:
In HS with LVH in comparison with N, the increase of the LA contractility is considered to be urged by the increase of LAV (Frank-Starling's law). These data could be explained by the less distensibility of LV chamber in relation to LVH.