Fundamentals of Anatomy and Physiology

The Cardiovascular Circulatory System 337

Common Disease, Disorder, or Condition

Disorders of the Cardiovascular System

RHEUMATIC HEART DISEASE^

Rheumatic (roo-MAT-ik) heart disease usually occurs in young children rather than

adults. It results from untreated infections with the bacterium Streptococcus (strep-toh-

KOK-us). The bacteria produce a toxin, which causes an immune reaction called

rheumatic fever anywhere from 2 to 4 weeks following the infection. This causes an

inflammation of the endocardium of the heart. Especially affected is the bicuspid valve,

which can become narrowed, resulting in incompetence of the valve. Antibi-otic

treatments have reduced the frequency of this disease.^
Endocarditis^
Endocarditis (en-doh-car-DYE-tis) is an inflammation of the endocardium.

Myocarditis^
Myocarditis (my-oh-car-DYE-tis) is an inflammation of the myocardium, which can

cause a heart attack.^
Pericarditis^
Pericarditis (pair-ih-car-DYE-tis) is an inflammation of the pericardium caused by viral

or bacterial infection and is very painful.^
Atherosclerosis^
Atherosclerosis (ath-er-oh-skleh-ROH-sis) is a disease of the arteries in which
-cholesterol-containing masses called plaque accumulate on the inside of arterial walls.
They interfere with blood flow by blocking part of the lumen of the blood vessel. They
form a roughened surface that can initiate the clotting mechanism, which can result in
an embolus or thrombus. This can result in the death of tissues beneath the plaque. The
walls of the artery affected can become hardened or scle-rotic, lose their elasticity, and
degenerate. Such vessels may rupture. A number of procedures are used to clear
clogged arteries, such as angioplasty and bypass graft surgery. However, the best way
to avoid atherosclerosis is by modifying one’s be-havior: avoid fatty diets, do not smoke,
control your weight, and exercise. Elevated blood pressure may also be a risk for

developing atherosclerosis.^
Coronary Heart Disease^
Coronary heart disease results from reduced blood flow in the coronary arteries that
supply the myocardium of the heart. As we age, the walls of these arteries thicken and
harden, reducing blood volume. This reduced blood flow causes a sensation of pain in
the chest, left arm, and shoulder called angina pectoris (an-JYE-nah PEK-toh-ris).
Inadequate blood flow can cause an infarct (in-FARKT), an area of damaged cardiac
tissue. A heart attack is commonly referred to as a myocardial infarction. The degen-
erative changes in the coronary arteries cause the walls to be roughened with plate-let
aggregation, resulting in a blood clot in the vessel called a coronary thrombosis. If the
infarct is large, death can result. However, if it is small, although weakened, the heart
can function even though the walls of the heart may be weakened due to the
development of scar tissue in the infarct area. Myocardial infarctions can be prevented
by moderate exercise, rest, good diet, and lowering stress. Small doses of aspirins and
drug treatments can also help.