A modified version of the New York Heart Associations’ system for classifying heart failure is also used to assess the severity of Pulmonary hypertension. The WHO, along with the American College of Chest Physicians, supports using this system to assess the functional status of Pulmonary hypertension patients. Functional status is delineated into 4 possible classes, with severity of symptoms determining class. Presents the WHO Functional Classes (WHO-FC) for Pulmonary hypertension