Echocardiographic left atrial remodelling and determinants of left atrial size in the early phase of high blood pressure: a comparative cross-sectional study in Douala, Cameroon.

Abstract

Left atrial remodelling (LAR) has been described in Western populations with chronic hypertension and is associated with a higher risk of adverse cardiovascular events. Although hypertension tends to occur earlier and is more severe in sub-Saharan Africa than in more developed nations, LAR and its associated factors in these African hypertensive subjects have been poorly elucidated. To assess left atrial structural remodelling in black hypertensive patients and determine factors associated with left atrial size. This was a cross-sectional, comparative study carried out in two tertiary hospitals in Douala, Cameroon over a period of three months. Fifty-two patients, either newly diagnosed with hypertension or known hypertensives treated for less than a year, were consecutively recruited. These patients were matched (unpaired matching) for age and gender to 40 randomly selected healthy subjects. The posterior-anterior diameter indexed to body surface area (BSA), volume indexed to BSA, and longitudinal and transverse diameters of the left atrium (LA) were measured using transthoracic echocardiography, in accordance with the American Society of Echocardiography guidelines. LAR was defined as increase in LA size, characterised by LA volume ≥ 34 ml/m2. Early morning urine was analysed for microalbuminuria using urine strips to obtain spot albumin/creatinine ratio. Data were analysed using SPSS version 23 and statistical significance was set at p < 0.05. The gender distribution and mean age were similar between the two groups. Hypertensive patients had significantly higher mean body mass index, left ventricular mass and an altered diastolic function. They also had significantly higher LA longitudinal diameter (50.0 vs 47.4 mm; p = 0.045), surface area (17.9 vs 15.5 cm2; p = 0.003) and volume (52.4 vs 43.8 ml; p = 0.002) compared to the non-hypertensive counterparts. Fourteen patients (26.9%) had LA enlargement compared to one (2.5%) in the non-hypertensive group (odds ratio = 9.78, CI: 2.67-35.8, p < 0.0001). Diastolic dysfunction (p = 0.008) was the only independent predictor of LA size in the hypertensive subjects. Microalbuminuria did not significantly correlate with LA size. Our study shows evidence of LAR in newly diagnosed black African patients with hypertension, characterised by an increase in the LA length, surface area and volume. Future studies are warranted to better elucidate the biological mechanisms underlying the link between the early phase of hypertension and LAR, as well as its prognostic implications in our population.