CHF (congestive heart failure) usually occurs because a problem makes the heart muscle weak or stiff.
Some of these problems are:
- Coronary artery disease, usually with a previous heart attack (myocardial infarction)
- Heart muscle disease (cardiomyopathy)
- High blood pressure (hypertension)
- Heart valve disease
- Severe lung disease
Coronary artery disease
This disease is the end process of hardening of the arteries (atherosclerosis). It is the most common cause of a heart attack (myocardial infarction). When you have coronary artery disease, the blood vessels that supply oxygen rich blood to the heart are narrowed by plaque build-up in these vessels. This buildup narrows the opening (lumen) of the vessel, so blood has a difficult time passing through to the heart muscle itself.
As a result, a part of the heart will not get the proper amount of oxygen-rich blood. The area deprived will become too weak to pump the blood effectively. The rest of the heart will have to pick up this work load. This strain and extra work load may lead to the heart getting tired out.
Cardiomyopathies (pronounced KAR-dee-ohmy-AW-pa-theez) refers to a group of diseases that damage the heart muscles and lead to congestive heart failure. A few kinds of cardiomyopathies exist:
- Dilated (pronounced DYE-lay-ted) cardiomyopathy involves an enlarged heart ventricle. The heart dilates and the muscular wall becomes thin. The overall pumping action is reduced.
- Hypertrophic (pronounced hy-per-TROfik) cardiomyopathy also is associated with CHF. In this case, the heart muscles become thick and contract with difficulty. Because of these difficulties, the heart is not an effective pump.
Heart attack (myocardial infarction)
When a coronary artery is completely blocked and blood flow is stopped to part of the heart muscle near that artery, a heart attack occurs. This is referred to as a myocardial infarction (pronounced my-oh-KAR-dee-ul in-FARKshun). Once this happens, the damage is not reversible. The damaged part of the heart loses its ability to pump. The rest of the heart tries to take on that work load. After some time of doing that extra work, the heart is tired and strained. Eventually, it pumps less blood to the body.
Blood pressure is the force pushing blood through the vessels of the body. When your blood pressure is high, your body has to work harder to deliver the blood. Because of this extra hard work load, high blood pressure (also known as hypertension) causes the heart muscle to thicken to compensate for the increased blood pressure. These changes put even more strain on the heart. The heart muscle eventually stretches and weakens. Once this occurs, the heart no longer has the ability to fill normally with blood.
Heart valve disease
Sometimes the heart valves themselves are not working properly. This can lead to heart failure. The valves between the chambers of the heart control the flow of blood leaving and entering the heart. Two main types of abnormalities can occur that lead to failure:
- The valves can become narrow (stenosis) and cause a back-up of blood.
- The valves can close improperly, causing blood to leak backward (insufficiency).
Either way, the heart has to work harder. Narrowing forces the heart to pump harder to try to force blood through the narrow (stenotic) area to eject the blood into the next chamber. Extra work also is added when a valve does not close properly. The heart has to pump the same blood through the valve over and over.
Over time, both of these extra work-load conditions can lead to congestive heart failure. Sometimes valve problems resulting from rheumatic fever or birth defects can cause heart failure.
Who gets CHF?
Some people are more likely to get CHF than others. A person’s risk for getting CHF depends on a number of factors.
- Age- Older adults are the group most affected by CHF. In this age group, CHF is the most common reason for hospitalization.
- Gender- Men are at higher risk, although the gap narrows with age. Women are more likely to develop CHF after a heart attack.
- Ethnicity. For instance, African Americans are at higher risk than Caucasians.
- Family history- A family history of early CHF caused by cardiomyopathies may make some people more likely to get the disease.
- Chronic alcohol abuse- Chronic alcohol abuse can damage the heart muscles and can cause hypertension and dilated cardiomyopathy.