Pulmonary hypertension (PH or PHTN) is an increase of blood pressure in the pulmonary artery, pulmonary vein, or pulmonary capillaries, together known as the lung vasculature, leading to shortness of breath, dizziness, fainting, leg swelling and other symptoms. Pulmonary hypertension can be a severe disease with a markedly decreased exercise tolerance. It was first identified by Ernst von Romberg in 1891. According to the most recent classification, it can be one of six different types.