Background: Left atrial enlargement (LAE) is a marker of hypertensive heart disease associated with increased cardiovascular risk. We reviewed recent literature about the prevalence of LAE, as assessed by echocardiography, to update our information about the clinical relevance of this cardiac phenotype in human hypertension.
Methods: We performed a search of MEDLINE using the key words "left atrial enlargement," "left atrial dilatation," "left atrial size," "hypertension," "echocardiography," and "atrial fibrillation" to identify relevant papers. We considered full articles published in English from January 1, 2000 to July 1, 2012 reporting studies involving adult individuals.
Results: We analyzed a total of 15 studies, including 10,141 untreated and treated subjects. LAE was defined according to 11 different criteria (4 studies applied two or three criteria), and its prevalence consistently varied among studies, from 16.0-83.0%, with a prevalence in the pooled population of 32%. A gender-based analysis of 9 studies (8,588 patients) showed the prevalence of LAE as being similar in women and men (OR, 1.23; 95% CI, 0.83-1.83; P = 0.30). Data provided by 10 studies (n = 9,354 patients) showed the prevalence of left-ventricular hypertrophy as being significantly higher in patients with LAE (68.2%) than in their counterparts without LAE (41.8%) (OR, 2.97; 95% CI, 2.68-3.29; P < 0.01).
Conclusions: Our analysis shows that LAE is present in a relevant fraction of the hypertensive population. Because LAE is an independent predictor of cardiovascular events, the accurate detection of this phenotype may improve the evaluation of risk in hypertensive patients.