Causes
Heart failure has many causes and can evolve in different ways.
- It can be a direct, last-stage result of heart damage from one or more of several heart or circulation diseases.
- It can occur over time as the heart tries to compensate for abnormalities caused by these conditions, a condition called remodeling.
In all cases, the weaker pumping action of the heart means that less blood is sent to the kidneys. The kidneys respond by retaining water and salt. This in turn increases edema (fluid buildup) in the body, which causes widespread damage.
High Blood Pressure
Uncontrolled high blood pressure (hypertension) is also a major cause of heart failure even in the absence of an heart attack. In fact, about 75% of cases of heart failure start with hypertension. It generally develops as follows:
- The heart muscles thicken to make up for for increased blood pressure.
- The force of the heart muscle contractions weaken over time, and the muscles have difficulty relaxing. This prevents the normal filling of the heart with blood.
[For more information, see In-Depth Report #14: High blood pressure.]
Coronary Artery Disease
Coronary artery disease is the end result of a complex process called atherosclerosis (commonly called "hardening of the arteries"). It is the most common cause of heart attack and involves the build-up of unhealthy cholesterol in the arteries, with inflammation and injury in the cells of the blood vessels. The arteries narrow and become brittle. Heart failure in such cases most often results from a pumping defect in the left side of the heart. [For detailed information, see In-Depth Report #3: Coronary artery disease and angina and In-Depth Report #23: Cholesterol.]
 | Click the icon to see an image of atherosclerosis. |
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