What is Pulmonary Embolism

Pulmonary embolism is the sudden blockage of a major artery in the lung. This is usually due to a blood clot that developed in another part of the body, broke off and travelled with the blood stream into the lung circulation, blocking the pumping of the heart and oxygen uptake. The most frequent source of these blood clots (thrombi) is the deep vein circulation of the legs, a condition known as deep vein thrombosis.