Prognostic Implications of Small Left Atria on Hospitalized Patients

Purpose: We aimed to determine the association between small left atria (LA) and outcome in a relatively large heterogeneous population of hospitalized patients.

Methods: This is a single center retrospective study which included all inpatients who underwent an echocardiographic assessment between 2011-2016 and had an available left atrial volume index (LAVI) measurement.

Results: Overall 17,344 inpatients had an available LAVI measurement. The study group consisted of 288 patients with small LA (2 - the lowest 1.7^th percentile in our cohort). The control group consisted of 7,531 individuals with LAVI within normal limits (16-34 ml/m²). After adjustments for baseline characteristics (age, gender, body mass index, hemoglobin, ischemic heart disease, valvulopathy, atrial fibrillation, diabetes mellitus, hypertension, hyperlipidemia, smoking, renal dysfunction, lung disease, malignancy) patients with small LA had a higher risk for overall (HR 1.68, 95% CI 1.27-2.21; p<0.001), 1-year (OR 1.86, 95% CI 1.31-2.63; p=0.001), 30-days (OR 2.34, 95% CI 1.25-4.4; p=0.008) and in-hospital mortality (OR 2.2, 95% CI 1.12-4.32; p=0.022). The risk for mortality was higher as LA volume decreased, in comparison to patients with LAVI within normal limits. In addition, we have shown that the presence of large LA (≥87.71 ml/m², i.e. the upper 1.7^th percentile; n=296) predicted mortality similarly to small LA, after adjustments for baseline characteristics (HR 1.03, 95% CI 0.65-1.64; p=0.9).

Conclusion: Small LA is an independent predictor of short and long term mortality. The outcome of patients with small LA was equally unfavorable as the outcome of patients with large LA, a known marker of adverse cardiovascular outcomes.