Congestive heart failure develops when the heart can't keep up with the body's demand for blood, according to Johns Hopkins Medicine. This reduces blood flow to other tissues and causes blood to back up into the lungs.
Congestive heart failure sometimes occurs as a complication of heart attack, cardiomyopathy or coronary artery disease, reports WebMD. Kidney disease, diabetes, high blood pressure and heart valve disease also increase the risk of congestive heart failure. The symptoms of CHF include dizziness, weakness, fatigue, irregular heartbeats and shortness of breath. CHF also causes water retention, resulting in swelling of the legs, abdomen and ankles.