Management of primary pulmonary hypertension is usually difficult because the disease is uncommon and the aetiology of the disease is not well understood. The disease is potentially lethal because it can lead to failure of the right ventricle, low cardiac output, and ensuing multiple organ failure. We report the successful treatment of a case of low-output syndrome due to primary pulmonary hypertension using combined drug therapy and atrial septostomy. Latest developments in the treatment of this disease are also discussed.