The patient with pulmonary hypertension still mystifies even the most astute of physicians. Pulmonary hypertension can be the result of multiple and diverse etiologies, and these include congenital heart defects, chronic lung disease, hepatic disorders, especially with portal hypertension, and autoimmune disease, particularly scleroderma. It can also arise as an unexplained condition. In the case of a congenital heart defect, the high flow and pressure are thought to be significant etiologically. If the primary etiol-Ž ogy is treated in a timely fashion eg, repair of a congenital heart defect in early infancy, or improvement in a