The imbalance of Starling's forces was investigated in 25 elderly patients hospitalized for acute diastolic heart failure. Tissue Doppler evidence of elevated left ventricular filling pressures was present on admission in 17 patients with high B-type natriuretic peptide (BNP) levels. Serum proteins concentrations and colloid osmotic pressure, related to malnutrition and severe sepsis, were significantly less in the 8 patients without tissue Doppler evidence of elevated filling pressures, and a high level of BNP was consistent with paroxysmal elevation in filling pressures in this setting.