Text 2 Read the text and answer the questions:
What is the CHF?
What is the mechanism of the CHF?
In what way is the CHF manifested?
How does the CHF affect the other organs?
Congestive Heart Disease
Congestive heart failure (CHF) is a condition in which the heart’s function as a pump is inadequate to deliver oxygen rich blood to the body. Congestive heart failure can be caused by: diseases that weaken the heart muscle, diseases that cause stiffening of the heart muscles, or diseases that increase oxygen demand by the body tissue beyond the capability of the heart to deliver adequate oxygen-rich blood.
Many diseases can impair the pumping action of the ventricles. For example, the muscles of the ventricles can be weakened by heart attacks or infections (myocarditis). The diminished pumping ability of the ventricles due to muscle weakening is called systolic dysfunction. After each ventricular contraction (systole) the ventricle muscles need to relax to allow blood from the atria to fill the ventricles. This relaxation of the ventricles is called diastole.
Diseases such as haemochromatosis (iron overload) or amyloidosis can cause stiffening of the heart muscle and impair the ventricles’ capacity to relax and fill; this is referred to as diastolic dysfunction. The most common cause of this is longstanding high blood pressure resulting in a thickened (hypertrophied) heart. Additionally, in some patients, although the pumping action and filling capacity of the heart may be normal, abnormally high oxygen demand by the body’s tissues (for example, with hyperthyroidism or anaemia) may make it difficult for the heart to supply an adequate blood flow (called high output heart failure).
In some individuals one or more of these factors can be present to cause congestive heart failure. Congestive heart failure can affect many organs of the body. For example: the weakened heart muscles may not be able to supply enough blood to the kidneys, which then begin to lose their normal ability to excrete salt (sodium) and water. This diminished kidney function can cause the body to retain more fluid.
The lungs may become congested with fluid (pulmonary oedema) and the person’s ability to exercise is decreased. Fluid may likewise accumulate in the liver, thereby impairing its ability to rid the body of toxins and produce essential proteins. The intestines may become less efficient in absorbing nutrients and medicines. Fluid also may accumulate in the extremities, resulting in oedema (swelling) of the ankles and feet. Eventually, untreated, worsening congestive heart failure will affect virtually every organ in the body.