Pulmonary hypertension is a condition in which high blood pressure builds up in the arteries that supply blood to the lungs. It can cause right-sided heart failure, leading to complications such as: * Right ventricular enlargement and failure * Blood clots * Irregular heartbeats (arrhythmias) * Bleeding in the lungs Risk factors for pulmonary hypertension include: * A family history of the condition * Being overweight * Blood-clotting disorders or a family history of blood clots in the lungs * Exposure to asbestos * Congenital heart disease * Living at a high altitude * Use of certain drugs, including some weight-loss medicines and illegal drugs such as cocaine or methamphetamine * Use of selective serotonin reuptake inhibitors (SSRIs), used to treat depression and anxiety Pulmonary hypertension can be caused by: 1. Pulmonary arterial hypertension (PAH) 2. Left-sided heart disease, such as mitral valve or aortic valve disease 3. Lung disease, including chronic obstructive pulmonary disease (COPD) and scarring of the tissue between the lung's air sacs (pulmonary fibrosis) 4. Chronic blood clots in the lungs (pulmonary emboli) 5. Blood disorders, including polycythemia vera and essential thrombocythemia 6. Inflammatory disorders, such as sarcoidosis and vasculitis 7. Metabolic disorders, including glycogen storage disease 8. Kidney disease 9. Tumors pressing against pulmonary arteries