by Alicia M Prater PhD

Created on: September 18, 2009   Last Updated: October 14, 2010

Congestive heart failure (CHF) is one type of heart failure, a condition in which the heart can no longer work efficiently. CHF occurs when a dilated heart cannot pump blood into the circulation, a condition that is not compatible with life. As such, congestive heart failure is often the endpoint of many types of heart disease, lung disease, and hypertension that occurs after many years of accumulated strain on the heart muscle.

Disease, Congestion, and Failure

The term "heart disease" most commonly refers to ischemic heart disease, a situation in which not enough blood is supplied to the heart muscle. When the heart tissue begins to die and becomes scarred from infarctions (heart attacks, a complete lack of oxygen to a portion of the tissue), it is no longer able to efficiently eject blood through the aorta via contraction. The heart muscle relies on strength and elasticity to fully contract, both of which are compromised when the tissue is not healthy. An inability to eject the blood out of the heart is called forward failure. This initial event compromises circulation, resulting in kidney and liver problems.

This lack of pumping causes the heart to abnormally fill with blood, resulting in dilatation, or stretching, of the chambers and congestion of the venous system, which provides the term "congestive" to describe the failure. The blood remaining in the heart initially backs up into the blood vessels of the lungs, leading to pulmonary edema, an accumulation of fluid in the lungs. The congestion continues to affect upstream vessels, resulting in backward failure. 

Compensated vs. Decompensated Heart Failure

Compensated heart failure is the maintenance of output despite the dilatation, which can be described as a balloon filling with air as the heart fills with blood and works against the extra load. The heart may meet the output demand by increasing the heart rate or increasing the contraction force of the ventricles. Eventually, the heart can no longer meet the demand, even by compensating, and decompensated heart failure ensues, resulting in death.

Left-side vs. Right-side Heart Failure

The first side of the heart to fail is the left. This is easily remembered by knowing that pulmonary edema is one sign of congestive heart failure. The pulmonary vessels connect the right side to the left, which ejects blood through the aorta. Left-sided failure is most often caused by hypertension, ischemic heart disease (often caused by heart attacks), mitral or aortic valve disease, and primary myocardial diseases. Right-side failure is most often a result of left-side heart failure, though it can also occur as a result of cor pulmonale, which is most often caused by chronic obstructive pulmonary disease (COPD), a disorder associated with long-term cigarette smoking.

Treating Congestive Heart Failure

There are medications available to treat congestive heart failure and maintain cardiac output. These compounds remove excess water and salt to limit the pressure in the compromised circulation, such as furosemide (lasix) and anti-hypertensive drugs, in particular angiotensin receptor blockers (ARBs) and ACE inhibitors. Digitalis and dobutamine are also used because they strengthen the heart muscle and heart function over weeks and months. There are also surgical remedies, depending on the particular case, that can be discussed with a physician.

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