Heart failure (HF) occurs when the heart muscle is weakened. This affects the pumping action of the heart.
When the right side of the heart is weakened, it can’t handle the blood it is getting from the rest of the body. This blood returns to the heart through veins. When too much pressure builds up in the veins, fluid leaks out into the tissues. Gravity then causes that fluid to spread to those parts of the body that are the lowest. So one of the first symptoms of HF is swelling in the feet and ankles. If the condition worsens, the swelling can even go up past the knees.