338 Chapter 14
Common Disease, Disorder, or ConditionDisorders of the Cardiovascular System continuedHeart Failure^
Several heart diseases develop as people age. Heart failure is caused by progressive
weakening of the myocardium and failure of the heart to pump adequate amounts of
blood.
Hypertension^
Hypertension or high blood pressure can cause enlargement of the heart leading to
heart failure. Besides hereditary factors, malnutrition, hyperthyroidism, chronic in-
fections, anemia, and advanced age can lead to heart failure.
Congenital Heart Disease^
Heart disease present at birth is known as congenital heart disease. The heart does
not develop properly. Two common congenital heart defects are septal defect and
stenosis of the heart valves. Septal defect is a hole in the interatrial or interventricu-lar
septum between the left and right sides of the heart. This reduces the pump-ing effect of
the heart. Stenosis of the heart valves is a narrowed opening through the valves. In
pulmonary or aortic semilunar valve stenosis, the ventricles must work harder to pump
blood. Stenosis of the mitral valve causes blood to backflow into the left atrium and the
lungs, causing lung congestion. Stenosis of the tricus-pid valve causes blood to back up
in the right atrium and superior and inferior venae cavae.
Having regular checkups to monitor arterial pulse rates and blood pressure is a
good way to monitor the efficiency of our cardiovascular system.Arrhythmia^
An arrhythmia (ah-RITH-me-ah) is any deviation from a normal heartbeat rhythm.
There are several kinds; two examples are bradycardia, which is a slow heartbeat rate
of less than 60 beats per minute, and tachycardia, which is a fast heartbeat rate of more
than 100 beats per minute and can be brought on by excessive sympathetic innervation
by the autonomic nervous system, elevated body temperature, or drug interactions.
Heart Murmur^
A heart murmur is an abnormal heart sound akin to a fluttering or a humming sound
like a gentle blowing. A heart murmur is indicative of a heart abnormality such as a
stenosis of a heart valve or an incompetent heart valve.
Stenosed Heart Valve^
A stenosed heart valve (stenosis of a heart valve) is one that has an abnormal
opening that is narrowed. This produces a rushing sound just before the valve closes.
This is due to the fact that blood flows in a very turbulent way producing an abnormal
sound. Stenosed tricuspid or bicuspid valves produce the rushing sound just before the
first thump in a heartbeat while a stenosed aortic or pulmonary semilunar valve
produces the sound just before the second thump in a heartbeat.