present in other tissue, and blood levels may be elevated as a result of damage to
skeletal muscles, the liver, the kidneys, and other organs. This results in a false
d. Isoenzymes. Isoenzymes are forms of enzymes that can be differentiated
from one another.
(1) One isoenzyme of the enzyme CPK is present in significant amounts
only in myocardial tissue. This isoenzyme is identified as CPK-MB.
(2) Lactic dehydrogenase has five isoenzymes, and cardiac muscle is
associated with large amounts of the isoenzymes LDH1.
(3) The determination of the isoenzymes (CPK-MB and LDH is more
specific in evaluation myocardial damage than simple enzyme determinations.
a. Each time the heart beats, the left ventricle contracts and sends blood
through the arteries. The pulse is the rhythmic expansion of the arteries that results
from each heartbeat. The pulse may be felt most strongly over the following areas:
Radial artery in the wrist at the base of the thumb.
Temporal artery in front of the ear.
Carotid artery in the neck.
Femoral artery in the groin.
Over the apex (tip) of the heart (apical pulse).
b. Two other locations for palpation of the pulse are the popliteal artery at the
back of the knee and the pedal pulses of the foot. Pedal pulses are located on both the
lateral and medial aspects of the ankle and on the top of the foot. These pulses are
often difficult to locate.
c. The physician may request that both a radial and apical pulse be taken
simultaneously to see if there is a difference in rates. A significant difference is
indicative of vascular disease. This difference between the apical and radial pulse is
known as the pulse deficit.