Left atrial volume as an index ofleft atrial size: a population-based study

Objectives We studied left atrial volume (LAV) as an index of atrial size. Background Increased left atrial dimension (LAD) measured by M-mode echocardiography is a risk factor for atrial fibrillation, stroke, and death. Methods A random sample of residents of Olmsted County, Minnesota, age ≥45 years (n = 2,042) underwent Doppler echocardiography with assessment of LAD and LAV. A subgroup of the population (n = 767) with no cardiovascular disease and normal systolic and diastolic function was used to develop reference ranges for LAD and LAV. In the total population, the prevalence of left atrial enlargement and the association between cardiovascular disease and left atrial size as determined by both indexes were assessed. Results In the normal subgroup, both indexes were associated with gender and body size, thus models controlling for body size were used to determine gender-specific reference ranges for LAD and LAV. In the total population, left atrial enlargement was common, with a prevalence of 18% (men) and 12% (women) using LAD/body surface area (BSA) and of 16% (men and women) using LAV/BSA. The agreement between the indexes was only fair (kappa = 0.53). Adjusting for age and gender, LAV/BSA was more strongly associated with the presence of cardiovascular diseases than LAD/BSA. Conclusions We described a simple technique of measuring LAV, examined methods for indexing LAV, and described its normal range in a large, healthy reference cohort. Further, we find that in the community, left atrial enlargement is common and reflects the burden of cardiovascular disease.