Lippincott Chapter 20: Antiarrhythmics Flashcards
20.1 A 60-year-old woman had a myocardial infarction.
Which of the following should be used to prevent
life-threatening arrhythmias that can occur post–
myocardial infarction in this patient?
A. Digoxin.
B. Flecainide.
C. Metoprolol.
D. Procainamide.
E. Quinidine.
Correct answer = C. β-Blockers such as metoprolol prevent
arrhythmias that occur subsequent to a myocardial infarc-
tion. None of the other drugs has been shown to be effec-
tive in preventing postinfarct arrhythmias. Flecainide should
be avoided in patients with structural heart disease.
20.2 Suppression of arrhythmias resulting from a reentry
focus is most likely to occur if the drug:
A. Has vagomimetic effects on the AV node.
B. Is a β-blocker.
C. Converts a unidirectional block to a bidirectional
block.
D. Slows conduction through the atria.
E. Has atropine-like effects on the AV node.
Correct answer = C. Current theory holds that a reentrant
arrhythmia is caused by damaged heart muscle, so that
conduction is slowed through the damaged area in only one
direction. A drug that prevents conduction in either direction
through the damaged area interrupts the reentrant arrhyth-
mia. Class I antiarrhythmics, such as lidocaine, are capable
of producing bidirectional block. The other choices do not
have any direct effects on the direction of blockade of con-
duction through damaged cardiac muscle.
20.3 A 57-year-old man is being treated for an atrial
arrhythmia. He complains of dry mouth, blurred vision,
and urinary hesitancy. Which antiarrhythmic drug is he
mostly like taking?
A. Metoprolol.
B. Disopyramide.
C. Dronedarone.
D. Sotalol.
Correct answer = B. The clustered symptoms of dry mouth,
blurred vision, and urinary hesitancy are characteristic of
anticholinergic adverse effects which are caused by class
IA agents (in this case, disopyramide). The other drugs do
not cause anticholinergic effects
20.4 A 58-year-old woman is being treated for chronic
suppression of a ventricular arrhythmia. After 1 week
of therapy, she complains about feeling severe upset
stomach and heartburn. Which antiarrhythmic drug is
the likely cause of these symptoms?
A. Amiodarone.
B. Digoxin.
C. Mexiletine.
D. Propranolol.
E. Quinidine.
Correct answer = C. The patient is exhibiting a classic
adverse effect of mexiletine. None of the other agents listed
are likely to cause dyspepsia
20.5 A 78-year-old woman has been newly diagnosed with
atrial fibrillation. She is not currently having symptoms
of palpitations or fatigue. Which is appropriate to
initiate for rate control as an outpatient?
A. Amiodarone.
B. Dronedarone.
C. Esmolol.
D. Flecainide.
E. Metoprolol.
Correct answer = E. Only C and E are options to con-
trol rate. The other options are used for rhythm control in
patients with atrial fibrillation. Since esmolol is IV only, the
only option to start as an outpatient is metoprolol.
20.6 Which of the following is correct regarding digoxin
when used for atrial fibrillation?
A. Digoxin works by blocking voltage-sensitive
calcium channels.
B. Digoxin is used for rhythm control in patients with
atrial fibrillation.
C. Digoxin increases conduction velocity through the
AV node.
D. Digoxin levels of 1 to 2 ng/mL are desirable in the
treatment of atrial fibrillation.
Correct answer = D. Digoxin works by inhibiting the Na+/K+-
ATPase pump. It decreases conduction velocity through the
AV node and is used for rate control in atrial fibrillation (not
rhythm control). Digoxin levels between 1 and 2 ng/mL are
more likely to exhibit negative chronotropic effects desired
in atrial fibrillation or flutter. A serum drug concentration
between 0.5 and 0.8 ng/mL is for symptomatic manage-
ment of heart failure.
20.7 All of the following are adverse effects of amiodarone
except:
A. Cinchonism.
B. Hypothyroidism.
C. Hyperthyroidism.
D. Pulmonary fibrosis.
E. Blue skin discoloration.
Correct answer = A. Cinchonism is a constellation of symp-
toms (blurred vision, tinnitus, headache, psychosis) that is
known to occur with quinidine. All other options are adverse
effects with amiodarone that require close monitoring.
20.8 Which arrhythmia can be treated with lidocaine?
A. Paroxysmal supraventricular ventricular
tachycardia.
B. Atrial fibrillation.
C. Atrial flutter.
D. Ventricular tachycardia.
Correct answer = D. Lidocaine has little effect on atrial or AV
nodal tissue; thus, it used for ventricular arrhythmias such
as ventricular tachycardia.
20.9 A clinician would like to initiate a drug for rhythm control
of atrial fibrillation. Which of the following coexisting
conditions would allow for initiation of flecainide?
A. Hypertension.
B. Left ventricular hypertrophy.
C. Coronary artery disease.
D. Heart failure.
Correct answer = A. Since flecainide can increase the risk
of sudden cardiac death in those with a history of struc-
tural heart disease, only A will allow for flecainide initiation.
Structural heart disease includes left ventricular hypertro-
phy, heart failure, and atherosclerotic heart disease.
20.10 Which statement regarding dronedarone is correct?
A. Dronedarone is more effective than amiodarone.
B. QT interval prolongation is not a risk with
dronedarone.
C. Dronedarone increases the risk of death in
patients with permanent atrial fibrillation or
symptomatic heart failure.
D. There is no need to monitor liver function with
dronedarone.
Correct answer = C. Dronedarone is not as effective as ami-
odarone, QT prolongation is a risk with this drug, and liver
function should be monitored when taking dronedarone
since it increases the risk of liver failure. The drug is con-
traindicated in those with symptomatic heart failure or per-
manent atrial fibrillation due to an increased risk of death.
