Introduction to Congestive Heart Failure

Congestive heart failure (CHF) occurs when the heart muscle is not able to pump enough blood to satisfy the metabolic needs of the tissues. Heart failure may be due to a primary disease of the heart muscle which is called cardiomyopathy, or may be secondary to diseases which affect the heart muscle such as hypertension, coronary heart disease, or various diseases of the heart valves.

Heart failure is divided into various types:

• Left-sided heart failure is failure of the left ventricle (larger chamber that pumps blood to the body). This may result in fluid accumulating in the lungs and the patient complaining of shortness of breath.

• Right-sided heart failure is failure of the right ventricle (chamber that pumps blood to the lungs) and may result in fluid accumulating in the abdomen and in the ankles.

Heart failure is further subdivided into systolic dysfunction and diastolic dysfunction:

• Systolic dysfunction is an abnormality of contraction of the pumping chambers of the heart.

• Diastolic dysfunction occurs when the pumping chamber may be contracting normally but does not relax properly (i.e., they are stiff).

It is important to try to understand the difference types of heart failure since the treatment may vary depending on the type.

When heart failure occurs, the body has compensatory mechanisms such as the renin-angiotensin-aldosterone system and the sympathetic nervous system which become activated. These systems produce many of the signs and symptoms of congestive heart failure. Many of the medications used to treat CHF act by blocking some of these mechanisms.