Heart failure is a condition in which the heart does not pump enough blood to meet the needs of the body's tissues.
Failure on the right side of the heart is most often a result of failure on the left side. Because the right ventricle receives blood from the veins, failure causes the blood to back up. As a result, the veins surrounding the heart fill up with blood and fluid. This fluid is pushed out into the body's tissues and causes swelling in the feet, ankles, legs and abdomen.
Pulmonary hypertension and lung disease may also cause right-side heart failure.