Prevalence and correlates of left atrial enlargement in essential hypertension: role of ventricular geometry and the metabolic syndrome

Abstract

The cardiac effects of hypertension include a variety of structural changes such as increases in left ventricular mass (LVM) and left atrium (LA) size. Although data on hypertension-induced left ventricular changes are extensive, relatively little information is available on LA size from large-scale studies. We sought to assess the prevalence of LA enlargement in a large selected hypertensive population and to determine the relations of LA size to several biologic variables including left ventricular hypertrophy (LVH) and metabolic disturbances. A total of 2500 untreated and treated uncomplicated essential hypertensives consecutively attending, for the first time, our hospital out-patient hypertension clinic and included in the Evaluation of Target Organ Damage in Hypertension, an observational ongoing registry of hypertension-related target organ damage (TOD), were considered for this analysis. All patients underwent extensive clinical, laboratory and ultrasonographic investigations searching for cardiac (and extracardiac) TOD. The LA was considered enlarged when its anteroposterior diameter exceeded 3.7 cm in women and 4.1 cm in men. LVH was defined according to two different criteria: >/= 125 g/m in men and >/= 110 g/m in women; or >/= 51 g/m in men and >/=47 g/m in women. Enlarged LA diameter was present in 24.5% of women and in 21.5% of men. Compared with 1925 patients with normal LA size, the 575 patients with enlarged LA were older, more frequently overweight, had higher systolic blood pressure and included a greater proportion of subjects under antihypertensive treatment, with diabetes and metabolic syndrome. Both LA size and prevalence of LA enlargement differed significantly in relation to left ventricular geometry and LVM, being greater in patients with concentric or eccentric LVH than in those with left ventricular concentric remodeling or normal geometry. The prevalence of LA enlargement was similar in patients with concentric and eccentric LVH. According to a logistic regression analysis, overweight, LVH, fasting blood glucose > 7.0 mmol/l and metabolic syndrome were the main independent predictors of LA enlargement in the overall population as well as in both untreated and treated hypertensive subgroups. Our study suggests that: LA enlargement is a common echocardiographic finding in selected essential hypertensive patients with different left ventricular geometric patterns; LA size and LA enlargement is related to LVM rather than the type of LVH; and, in addition to LVH, overweight, high fasting glucose and metabolic syndrome are associated with LA dimensions.