One of the problems inherent in understanding edema is that it is a common symptom for several different types of medical conditions. Cardiac edema occurs when your heart muscle is damaged by disease or overworked, and isn’t strong enough to pump out enough of the blood it receives from your lungs. This causes the heart to hold an excess amount of fluid; therefore, swelling.

Congestive heart failure occurs when the heart muscle is damaged, usually by a heart attack, and becomes too weak to pump blood efficiently throughout the body, causing some of it to back up in the tissues of legs, ankles, feet, or the abdomen. If you suffer from congestive heart failure, you should weigh yourself daily and alert your doctor if you gain two pounds in a day or five in a week.

Weight gain is one of the first signs of fluid retention, and can mean you need to adjust your diuretic dosage.

Myocarditis is the medical term for inflammation of the heart muscle. It can affect not only the muscle itself, but also the heart’s electrical system, reducing its ability to pump as well as causing rapid or abnormal heart rhythms known as arrhythmias.

Heart valve disease occurs when one of the heart’s four valves — the tricuspid, pulmonary, mitral, and aortic valves — doesn’t work properly. These keep the blood from the heart flowing through the body in the correct direction, but if they become diseased, blood can leak backward and lead to edema.

High blood pressure can damage the heart, and may cause diastolic dysfunction, a type of heart failure that makes it hard for the heart to pump blood throughout the body.