What is pulmonary hypertension (PH)?

Pulmonary hypertension is a rare lung disorder in which the arteries that carry blood from the heart to the lungs (pulmonary arteries) become constricted or narrowed. This in turn hinders the flow of blood through the vessels, causing blood pressure to rise above normal levels. As a result, the right ventricle of the heart is dangerously strained and becomes enlarged and weakened. This deterioration of the ventricle can eventually lead to heart failure.

Source: pph.pahcenter.org