 Methodology: Patients will be recruited from outpatient ILD and PH clinical services and will be consented prior to entering the study. We propose to study 48 patients over a 16 week period. Patients will be included in the study if they have fibrosing lung disease specifically: idiopathic pulmonary fibrosis or idiopathic fibrosing non-specific pneumonitis and have PH as determined by measurement on right heart catheter mean pulmonary artery pressure 25mmHg, pulmonary capillary wedge pressure 15mmHg. 