There are many causes of edema, one of which is related to heart failure, which is divided into left heart insufficiency and right heart insufficiency. Left heart insufficiency is mainly caused by pulmonary circulation, that is, from the lungs to the heart of the circulation appeared to be silt, the main blood silt in the lungs, the patient is mainly manifested as exertion dyspnea, after a long time will also cause generalized water and sodium retention, the emergence of double lower extremity edema. There is also a more likely cause of bilateral lower extremity edema is the right heart insufficiency, leading to the right heart insufficiency of the causes are very many, the most common causes such as pulmonary heart disease or pulmonary hypertension. Causes of pulmonary arterial hypertension is very much, there may be hundreds of diseases can cause pulmonary arterial hypertension, pulmonary arterial hypertension is the most important feature is because of the back of the heart, that is, the whole body’s blood to the heart to increase the resistance to return to the lower extremities of the double edema, and even jugular vein varicose, the cause of the pressure is big. Circulation is the blood of the whole body first through the superior vena cava and inferior vena cava flow to the right heart, the right heart and then through the pulmonary artery to the inside of the lungs, the lungs and then through the pulmonary veins to the left heart, the left heart and then hit the whole body. Heart failure, such as right heart insufficiency, is particularly likely to cause the whole body blood can not flow to the heart, like a dam, blocking the upstream of the dam will appear edema, especially for the lower extremities edema. Edema caused by heart failure is called scleroderma, which is also concave scleroderma, and is not the same as hypoproteinemia or other edema. The clinical manifestations are not the same, and the patient may have other manifestations such as decreased activity tolerance and shortness of breath after activity, which have to be judged in conjunction with the clinical manifestations.