Prognostic implications of small left atria on hospitalized patients.

Aims: To demonstrate the association between small left atria (LA) and outcome in a relatively large heterogeneous population of hospitalized patients.

Methods and results: In a single-centre retrospective study, all inpatients that underwent an echocardiographic assessment between 2011 and 2016 and had an available left atrial volume index (LAVI) measurement were included. The cohort consisted of 17 343 inpatients who had an available LAVI measurement, 288 with small LA (LAVI <16 mL/m2), 7531 patients had LAVI within normal limits (16-34 mL/m2) divided into low normal (16-24.9 mL/m2; n = 2636) and high normal (25-34 mL/m2; n = 4895), 4720 patients had large LAVI (34.1-45 mL/m2) and 4804 had very large LAVI (>45 mL/m2). Median follow-up time was 2.4 years. After adjustments for age, gender, and baseline characteristics with a P-value <0.2 in univariable analyses (body mass index, haemoglobin, ischaemic heart disease, valvulopathy, atrial fibrillation, diabetes mellitus, hypertension, hyperlipidaemia, smoking, renal dysfunction, lung disease, and malignancy) small LA was associated with a higher risk for in-hospital mortality (odds ratio 2.9, 95% confidence interval (CI) 1.4-5.7; P = 0.002] and all-cause mortality [hazard ratio (HR) 2.1, 95% CI 1.6-2.8; P < 0.001] compared with high normal LA. For every mL/m2 decrease below high normal LA size the risk for in-hospital and long-term all-cause mortality increased by 10% (HR 1.1, 95% CI 1.02-1.18; P = 0.005) and 8% (HR 1.08, 95% CI 1.05-1.12; P < 0.001), respectively.

Conclusion: Small LA are independently associated poorer short- and long-term mortality. LA volume should be referred to as J-shaped in terms of mortality.

Helsinki committee approval number: 0170-17-TLV.