Distinct role of minimal and maximal left atrial volumes in assessing LV filling pressures and prognosis in chronic heart failure.

Current guidelines recommend assessing left atrial (LA) maximal volume to grade left ventricular (LV) diastolic dysfunction. However, recent studies suggest a strong association between LA minimal volume and prognosis. The present study aims to investigate the relative merits of minimal and maximal LA volume in reflecting LV filling pressures and on prognosis in chronic heart failure (HF). We retrospectively analyzed 1135 chronic HF patients (75% men; mean age 66 ± 12 years) in sinus rhythm. LV end-diastolic pressure (EDP) ≥ 20 mmHg (estimated with echocardiography) was considered as increased LV-EDP. Patients were followed-up for the occurrence of all-cause death or HF hospitalization (primary composite endpoint). LA minimal volume (Area Under the Curve [AUC] = 0.74) demonstrated a stronger association with LV filling pressures compared to maximal volume (AUC 0.71, P-for-comparison = 0.007) and NT-proBNP. The superiority of LA minimal over maximal volume in identifying increased LV-EDP was more evident in patients with severe mitral regurgitation (MR, 12% of the cohort) or LV systolic dysfunction (LV ejection fraction < 50%, 84% of the cohort). Conversely, LA maximal volume (AUC = 0.77) performed better than minimal volume (AUC = 0.71) in identifying increased LV-EDP in patients with preserved LV ejection fraction. Multivariable Cox regression analysis revealed that both LA volumes were similarly and independently associated with the primary composite endpoint. In patients with chronic HF, although both minimal and maximal LA volumes are associated with clinical outcomes, minimal volume provides a more accurate reflection of LV filling pressures. This makes LA minimal volume a more valuable diagnostic parameter than maximal volume, especially in patients with severe mitral regurgitation and LV systolic dysfunction.