Heart failure is a serious condition in which the heart’s pumping action is compromised. In the early stages, heart failure may not have any symptoms. In the later stages, the patient may have severe symptoms because their weakened heart is unable to pump enough oxygen-rich blood with each contraction to satisfy the body. These symptoms may include shortness of breath (dyspnea), persistent coughing or wheezing and buildup of fluid (edema).

Heart failure is a chronic and complex condition. By itself, heart failure is not considered a disease. Rather, it is the result of other conditions that have damaged the heart. These conditions can include diseases of the coronary arteries that lay on the surface of the heart, heart valve disorders, high blood pressure and damage to the heart muscle itself.

According to the American Heart Association, heart failure affects about 5 million Americans, with more than half a million new cases diagnosed every year. Interestingly, while the incidence of other cardiac diseases remains stable or varies only slightly, the incidence of heart failure has increased significantly over the last three decades. This is because of the aging population and physicians’ increased ability to treat other cardiac diseases. In the 1970s, high blood pressure was the leading cause of heart failure. Today, coronary artery disease is the leading cause because of the increased survival due to treatments such as bypass surgery and balloon angioplasty.

In spite of its name, heart failure does not mean the heart has completely stopped, which is the case when someone has gone into cardiac arrest. Heart failure means the heart is not operating efficiently and therefore must work harder to make up for the shortcoming. For example, the heart may pump more frequently to compensate for its weakened pumping ability, or the size of its chambers may increase, especially the left ventricle.

The longer the heart must overwork to compensate for its shortcomings, the more its pumping ability is damaged and the more likely that serious pumping failure will result. Before a pumping failure occurs, however, various physical changes may take place in the heart and throughout the body as a result of the heart failure. They include:

Although the term heart failure usually refers to the chronic condition described in this article, there is also a condition known as acute heart failure. It is sudden in onset and usually results from a sudden catastrophic change in the heart (e.g., massive heart attack, endocarditis, ruptured or torn heart valve leaflets, aortic dissection). In acute heart failure, the heart muscle does not have time to thicken and enlarge. This condition is often fatal, even if emergency medical treatment is received immediately.