During the link heart failure (English: left sided heart failure) furnishes the left Herzkammer (ventricle) not sufficient achievement. This leads to a volume overloading of the small cycle (= Lungenvene, Lungenarterie). The blood, which flows out of the lung into the left Herzkammer, is also pumped to low pressure to the large cycle (= Venen, Arterien). Since the right Herzkammer works however normally, the blood accumulates in the Lungenarterie and flows off from the Lungevene too slowly.