Background Left atrial enlargement (LAE) is a common feature in patients with aortic stenosis (AS) and may reflect chronic pressure overload and diastolic dysfunction. Left ventricular (LV) systolic dysfunction is a late and adverse development in AS. While LAE is associated with adverse cardiovascular outcomes, its relationship with LV systolic dysfunction in severe AS remains unclear. This study investigates whether LAE predicts impaired LV systolic function in patients with severe AS.

Methods We retrospectively analyzed transthoracic echocardiograms (TTEs) performed from 1984 to 1998 at the University of California, Irvine. Severe AS was defined as an aortic valve peak flow velocity (AoPFV) ≥ 400 cm/s. LV systolic dysfunction was defined as fractional shortening (FS) < 25%. LAE was defined by American Society of Echocardiography guidelines as ≥ 40 mm in men or ≥ 38 mm in women (non-indexed), or ≥ 23 mm/m² when indexed to body surface area (BSA). Diagnostic performance of LAE for identifying systolic dysfunction was assessed using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results Among 222 patients with severe AS, 31 had concurrent LV systolic dysfunction. LAE was significantly associated with systolic dysfunction. Systolic impairment occurred in 16.8% of patients with LAE versus 2.3% without (p = 0.013). Mean FS was lower in patients with LAE (36.2 ± 10.9%) compared to those with normal LA size (40.1 ± 9.3%, p = 0.047). In the BSA-indexed cohort, systolic dysfunction was observed in 18.7% with LAE vs. 2.0% with normal LA size (p = 0.003). LAE demonstrated high sensitivity (non-indexed: 96.8%, indexed: 95.8%) and NPV (non-indexed: 97.7%, indexed: 98.0%), but low specificity and PPV for detecting systolic dysfunction.

Conclusion In patients with severe aortic stenosis, the absence of LAE is a strong predictor of preserved LV systolic function. LAE demonstrated high sensitivity and NPV for detecting systolic impairment, regardless of indexing. Given its ease of measurement, LA size may serve as a simple, non-invasive screening tool to preliminarily assess systolic function when advanced imaging is unavailable. These findings highlight a novel application of LA size as a potential indicator of preserved contractile performance in severe AS.