The first symptom of heart failure can be fatigue. As the condition gets worse, there can be shortness of breath and wheezing during exertion, and eventually also when you are resting. As fluid accumulates in the lungs, people with heart failure may begin to sleep propped up with pillows to make breathing easier. Fluid also can collect in the legs and ankles, causing swelling. In people who are less active, collected fluid can accumulate in the middle of the body. Some people need to urinate several times during the night as the kidneys drain off some of the excess fluid that accumulates in the lower body during the day. As the body accumulates more and more fluid, the person may notice significant weight gain. There also can be a chronic cough due to fluid accumulation in the lungs.
Although heart failure usually affects both sides of the heart, in some people it affects only the left or right side. In these cases, symptoms vary depending on which side is affected. When heart failure affects mainly the left side of the heart, the symptoms are more likely to involve breathing difficulties. When mainly the right side is affected, the main symptoms may be leg swelling and abdominal swelling.