Pulmonary arterial hypertension associated with another disease is a group of conditions that lead to PAH (see this term); connective tissue diseases (lupus erythematosus, systemic sclerosis and mixed connective tissues disease), congenital heart disease (Eisenmenger syndrome), HIV infection, portal hypertension, schistosomiasis and chronic hemolytic anemia (see these terms),which is characterized by elevated pulmonary arterial resistance leading to right heart failure that is progressive and potentially fatal.