LEHNE 9TH EDITION CHAPTER 49: ANTIDYSRHYTHMIC DRUGS
QUESTIONS AND ANSWERS 2022 LATEST
1. Which two classes of antidysrhythmic drugs have nearly
... [Show More] identical cardiac effects?
a.
Beta blockers and calcium channel blockers
b.
Beta blockers and potassium channel blockers
c.
Calcium channel blockers and sodium channel blockers
d.
Sodium channel blockers and potassium channel blockers - ANS: A
Calcium channel blockade has the same impact on cardiac action potentials as does
beta blockade, so these agents have nearly identical effects on cardiac function; that
is, they reduce automaticity in the SA node, delay conduction through the AV node,
and reduce myocardial contractility. Potassium channel blockers act by delaying
repolarization of fast potentials. Sodium channel blockers block sodium channels to
slow impulse conduction in the atria, ventricles, and His-Purkinje system.
2. A patient with atrial fibrillation is taking verapamil [Calan]. The patient has read
about the drug on the Internet and wants to know why a drug that affects the rate of
ventricular contraction is used to treat an abnormal atrial contraction. What will the
nurse tell the patient?
a.
"Drugs that treat ventricular dysrhythmias help to restore normal sinus rhythm."
b.
"Atrial dysrhythmias can have life-threatening effects on ventricular function."
c.
"Treating ventricular dysrhythmias helps prevent the likelihood of stroke."
d.
"When ventricular contraction slows, atrial contraction is also slowed." - ANS: B
Dysrhythmic activity in the atria does not significantly reduce cardiac output but can
be dangerous when dysrhythmic impulses cross the AV node, causing ventricular
dysrhythmias, which can be life threatening. Treating ventricular dysrhythmia helps
improve ventricular pumping. These drugs do not restore normal sinus rhythm. To
prevent stroke, an anticoagulant, such as warfarin, is used. Slowing ventricular
contraction does not affect the rate of atrial contraction. Restoring normal sinus
rhythm requires cardioversion, short-term treatment with amiodarone or sotalol, or
RF ablation of the dysrhythmia source.
3. A nurse is teaching a patient who is about to undergo direct-current (DC)
cardioversion to treat atrial flutter. The patient has been taking verapamil and
warfarin for 6 months. Which statement by the patient indicates understanding of the
teaching?
a.
"I may need long-term therapy with another cardiac medication after the procedure."
b.
"I should stop taking warfarin a few days before the procedure."
c.
"I will need to take a beta blocker after the procedure to prevent recurrence of atrial
flutter."
d.
"I will not have to take antidysrhythmia medications after the procedure." - ANS: A
After cardioversion for atrial flutter, patients may continue to need long-term therapy
with either a class IC agent or a class III agent to prevent recurrence. Patients
undergoing DC cardioversion need to take warfarin 3 to 4 weeks before the
procedure and for several weeks afterward. Beta blockers are not indicated for
postprocedural prophylaxis. Class IC and class III agents are antidysrhythmic drugs.
4. A nurse is teaching a group of nursing students about antidysrhythmic
medications. Which statement by a student indicates understanding of the teaching?
a.
"Antidysrhythmic drugs can cause new dysrhythmias or worsen existing ones."
b.
"Adverse effects of these drugs are mainly noncardiac in nature."
c.
"For most antidysrhythmic drugs, there is evidence of reduced mortality."
d.
"Use of these drugs may be necessary even if the benefits are unknown." - ANS: A
Because antidysrhythmic drugs have prodysrhythmic actions, they can exacerbate
existing dysrhythmias or generate new ones. Most adverse effects are cardiac
related. There is evidence of increased mortality with many of these drugs. Use of
these drugs should be limited to situations in which there is a clear benefit and only if
that benefit outweighs any risks.
5. A patient is taking digoxin [Lanoxin] and quinidine to treat sustained ventricular
tachycardia. Before giving medications, the nurse reviews the patient's
electrocardiogram (ECG) and notes a QRS complex that has widened by 50% from
the baseline ECG. What will the nurse do?
a.
Administer the medications as ordered, because this indicates improvement.
b.
Contact the provider to discuss reducing the digoxin dose.
c.
Contact the provider to request an increase in the quinidine dose.
d.
Withhold the quinidine and contact the provider to report the ECG finding. - ANS: D
Quinidine widens the QRS complex by slowing depolarization of the ventricles. As
cardiotoxicity develops as a result of quinidine toxicity, the QRS complex widens
excessively. Any widening of the QRS complex of 50% or more warrants notifying
the provider, so the nurse should withhold the medication and contact the provider.
Widening of the QRS complex by more than 50% of baseline indicates cardiotoxicity.
Quinidine can double digoxin levels, so it is not likely that the digoxin dose would
need to be increased, and an increase in the QRS complex does not indicate a need
for more digoxin. The quinidine dose should not be increased, because the findings
indicate cardiotoxicity from the quinidine.
6. A nurse provides teaching for a patient who will begin taking procainamide
[Procanbid] for long-term suppression of a dysrhythmia. Which statement by the
patient indicates a need for further teaching?
a.
"I need to take this drug at evenly spaced intervals around the clock."
b.
"I may have increased bruising, but this is a temporary side effect."
c.
"I should report pain and swelling in my joints when taking this drug."
d.
"I will need to have blood tests at regular intervals while taking this drug." - ANS: B
Blood dyscrasias are a rare but potentially fatal side effect of procainamide and are
an indication for withdrawing the drug. Procainamide should be taken around the
clock at evenly spaced intervals. Lupus-like symptoms may occur; inflammation of
the joints is one manifestation and should be reported so that antinuclear antibody
(ANA) titers can be monitored. Because of the risk of lupus-like symptoms and blood
dyscrasias, blood tests need to be done weekly at first and then periodically
thereafter.
7. A nurse is caring for a patient in the intensive care unit who is receiving
intravenous lidocaine. The patient is drowsy and confused and reports numbness of
the fingers and toes. Which standing order will the nurse initiate at this time?
a.
Administer diazepam.
b.
Reduce the rate of infusion.
c.
Discontinue the infusion.
d.
Prepare for mechanical ventilation. - ANS: B
This patient is showing signs that are common with high therapeutic levels of
lidocaine. Because lidocaine is rapidly degraded, slowing the rate of infusion can
help remove excess drug from the circulation. Seizures are possible with toxic
doses; diazepam should be used to control seizures. It is not necessary to
discontinue the infusion, because this patient is showing signs common to high
therapeutic doses. Respiratory arrest is possible with toxic doses; mechanical
ventilation may be needed.
8. A patient with diabetes develops ventricular tachycardia and is in the hospital for
evaluation of this condition. The nurse reviews the history and learns that the patient
takes mexiletine [Mexitil] for pain caused by peripheral neuropathy. What should the
nurse do?
a.
Discuss common side effects associated with taking mexiletine with cardiac agents.
b.
Understand that this drug will help with both peripheral neuropathy and
dysrhythmias.
c.
Notify the provider to request that another drug be used for peripheral neuropathy
pain.
d.
Request an order for renal function and hepatic function tests. - ANS: C
Mexiletine is an antidysrhythmic medication that can also cause dysrhythmias. It is
used to treat the pain associated with peripheral neuropathy in diabetic patients, but
it is contraindicated in diabetic patients with heart disease, and so it should be
stopped now that this patient has developed a heart disorder. Because it is
contraindicated, the nurse will not teach the patient about side effects with other
agents. It can exacerbate cardiac symptoms, so it should not be used to treat
dysrhythmias in diabetic patients. There is no indication for tests of renal and hepatic
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