Short-term infusion of dobutamine may determine a mild, statistically significant increase in pulmonary artery pressure from baseline in 30% of patients with moderate to severe heart failure despite systemic effects (changes in cardiac index and systemic vascular resistance) similar to those observed in patients showing a large reduction in right heart pressures. The increase in pulmonary artery pressure observed seems to be associated with a lower pulmonary diffusing capacity, probably reflecting a reduction in recruitment and distension capacity of pulmonary circulation.