Heart failure is one of the most common diseases, especially in ageing populations, affecting ≥10% of persons 70 years of age or older. There is a growing body of evidence that dyspnea in patients with heart failure is not only related to low cardiac output and pulmonary venous congestion, but also to functional and structural alterations of the lungs.Pulmonary hypertension is a well-known complication of heart failure, but recent evidence suggests that the alveolo-capillary membrane is also affected, at least in subgroups of patients with heart failure.