Congestive heart failure is the endpoint for many types of heart disease. If the heart is diseased, most commonly by ischemic heart disease, which is what is often meant when one uses the term “heart disease”, then the heart is eventually no longer able to eject blood through the aorta. This causes the heart to fill with blood, resulting in dilatation of the chambers and a congestion of the venous system, thus the term “congestive heart failure” (CHF).
How Congestive Heart Failure Occurs
If the heart is damaged it can no longer contract efficiently. The contraction is necessary for the heart to pump blood through the lungs and then out to the body. An inability to eject the blood out of the heart is called forward failure. This initial event in congestive heart failure results in kidney and liver problems as the circulation is compromised. The blood remaining in the heart initially backs up into the blood vessels of the lungs, leading to pulmonary edema, or an accumulation of fluid in the lungs. The congestion continues to affect preceding vessels and results in backward failure.
Compensated Versus Decompensated Heart Failure
Compensated heart failure is the maintenance of output despite the dilatation. The heart may do this by increasing the heart rate or increasing the contraction of the ventricles. Eventually the heart can no longer meet the demand, even by compensating, and decompensated heart failure ensues, resulting in death.
Left-sided Versus Right-sided 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-sided failure is most often a result of left-sided heart failure, though it also can occur as a result of cor pulmonale, which is most often caused by chronic obstructive pulmonary disease (COPD).
Treating Congestive Heart Failure
There are medications available to treat congestive heart failure and maintain the cardiac output. These compounds remove excess water and salt to limit the pressure in the compromised vascular system, such as furosemide (lasix), and anti-hypertensive drugs, in particular angiotensin receptor blockers (ARBs) and ACE inhibitors. Digitalis and dobutamine are also used as they strengthen the heart muscle and function over weeks and months.
There are also surgical remedies, depending on the particular case, that can be discussed with your physician.
Additional reference:
Kumar, Cotran, Robbins. Basic Pathology, 7th ed. Saunders.
