Page 1695 - Saunders Comprehensive Review For NCLEX-RN

prevent lead wire dislodgement.
3. Permanent pacemakers may be single-chambered, in
which the lead wire is placed in the chamber to be
paced; or dual-chambered, with lead wires placed in
both the right atrium and the right ventricle.
4. Biventricular pacing of the ventricles allows for
synchronized depolarization and is used for moderate
to severe heart failure to improve cardiac output.
5. A permanent pacemaker is programmed when
inserted and can be reprogrammed if necessary by
noninvasive transmission from an external
programmer to the implanted generator.
6. Pacemakers may be powered by a lithium battery with
an average life span of 10 years, nuclear-powered
with a life span of 20 years or longer, or designed to
be recharged externally.
7. Pacemaker function can be checked in the PHCP’s
office or clinic by a pacemaker interrogator or
programmer or from home, using a special telephone
transmitter device.
8. The client may be provided with a device placed over
the pacemaker battery generator with an attachment
to the telephone; the heart rate then can be
transmitted to the clinic.
9. Client teaching (Box 52-5).
VII. Coronary Artery Disease

A. Description

1. Coronary artery disease is a narrowing or obstruction
of 1 or more coronary arteries as a result of
atherosclerosis, which is an accumulation of lipid-
containing plaque in the arteries (Fig. 52-11).
2. The disease causes decreased perfusion of myocardial
tissue and inadequate myocardial oxygen supply,
leading to hypertension, angina, dysrhythmias, MI,
heart failure, and death.
3. Collateral circulation, more than 1 artery supplying a
muscle with blood, is normally present in the
coronary arteries, especially in older persons.
4. The development of collateral circulation takes time
and develops when chronic ischemia occurs to meet
the metabolic demands; therefore, an occlusion of a
coronary artery in a younger individual is more likely
to be lethal than one in an older individual.
5. Symptoms occur when the coronary artery is occluded
to the point that inadequate blood supply to the
muscle occurs, causing ischemia.
6. Coronary artery narrowing is significant if the lumen

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