How pulmonary hypertension develops

Blood normally travels from the right side of the heart through the pulmonary arteries, collects oxygen in the lungs, and returns to the left side. When the lung vessels narrow, stiffen, become blocked, or are exposed to low oxygen, blood meets greater resistance. Pressure rises upstream and the right ventricle must generate more force.

At first, the heart may compensate. Continued strain can enlarge or weaken the right ventricle, reduce the amount of blood reaching the body, and cause breathlessness, dizziness, fainting, tiredness, or ankle swelling. The mechanism differs according to whether the primary problem is in the vessels, heart, lungs, or clots.

A clinician combines symptoms and examination with tests such as oxygen measurement, an electrocardiogram, an echocardiogram, blood tests, chest imaging, and breathing tests. Further studies may assess clots, sleep-related breathing, heart valves, or other conditions. The purpose is to identify the mechanism, because treatment is chosen for the cause and the person's heart-lung function.

Keep appointments and report changes in exercise tolerance, fainting, chest discomfort, or swelling. Take prescribed medicines as directed and ask before changing activity, fluid intake, or medicines.

Get urgent help for severe breathlessness at rest, fainting, blue or grey lips, sudden chest pain, coughing blood, or rapidly worsening swelling. These signs can indicate a serious change in heart, lung, or blood-vessel function and require prompt assessment.

Where is the resistance occurring in my circulation? Is the right side of my heart under strain? Which tests will identify the mechanism? Which symptoms mean I should contact the team urgently, and how should I pace daily activity?