Left Atrial Function and Mortality in the Elderly

Background:
People over the age of 85 are the world`s most rapidly growing age group and provide an increasing challenge given their relatively high frequency of cardiac death. Previous studies have demonstrated that LA diameter and volume, which increase with age, are associated with mortality. Indices of LA function may provide incremental prognostic information beyond that obtained by LA size.

Methods:
Subjects were recruited from the Jerusalem Longitudinal Cohort that has followed subjects who were born between 1920 and 1921. Echocardiography was performed in randomly selected subjects. Maximum volume, minimal volume and volume prior to atrial contraction were determined. From measurements of these phasic volumes, phasic functions of the LA were calculated: LA expansion index (reflecting reservoir function); LA passive emptying fraction (reflecting conduit function); and LA active emptying fraction (reflecting booster function). Survival status at 5 year follow-up was assessed, and comparisons were made between the quartile with most impaired atrial function and the upper 3 quartiles.

Results:
A total of 274 subjects were included in the study of whom 87 (31.8%) had died at the time of the 5 year follow-up. There were no major differences between the groups examined in clinical data or LA volume. Survival of subjects in the lowest quartile was significantly lower compared to survival in the upper quartiles in LA expansion (28.5% vs. 43.3%, P=0.016) as well as LA active emptying (26.7% vs. 47.1%, p=0.001). When measurements of LA volume were added to the model, the relationship remained significant.

Discussion:
Utilizing home-based echocardiography, this study demonstrated that elderly subjects with significantly impaired LA function had increased 5 year mortality, independent of indices of LA volume. To our knowledge, this is the first study to use home echocardiography to address the effects of LA function on elderly prognosis.