Antiarrhythmic drug Questions Set #5

Anesthesia Pharmacology Chapter 9: Pharmacology of Antiarrhythmic Drugs Practice Questions

Factor/factors which may contribute to arrhythmia development:
1. abnormal origination (not SA node)
2. abnormal rate/regularity
3. abnormal conduction characteristics
Ionic gradients primarily responsible for cardiac transmembrane potential
1. sodium
2. potassium
3. calcium
Cardiac cell permeability and conductance:
1. current flow = voltage x conductance
2. conductance is determined by characteristics of the ion channel protein
Phase 0 of the cardiac action potential: except for specialize conducting tissue, the major inward depolarizing ion is sodium
1. true
2. false
Spontaneous depolarization (pacemaker cells):
1. phase 0
2. phase 1
3. phase 2
4. phase 3
5. phase 4
Factors/Factors that reduce the membrane potential and reduce conduction velocity:
1. hyperkalemia
2. ischemic cell damage
3. sodium pump blockade
Conduction in severely depolarized cells:
1. with decreased membrane potentials, e.g. -55 mV, sodium channels are inactivated
2. under some circumstances, increased calcium permeability or decreased potassium permeability allow for slowly conducting action potentials
3. Calcium-inward current-mediated action potentials or normal for specialized conducting SA nodal and nodal tissues
Proarrhythmic:
1. increased vagal tone
2. antiarrhythmic drugs
3. alkalosis
4. acidosis
5. hypoxia
Arrhythmias develop because of abnormal impulse generation, propagation or both.
1. true
2. false
More important determinant of heart rate:
1. action potential duration
2. diastolic duration interval
3. equally important
Determines/Determinants of diastolic duration interval
1. maximum diastolic potential
2. slope of phase 4 depolarization
3. Threshold potential
Decreased heart rate:
1. increased resting membrane potential (diastolic potential)
2. increased slope of phase 4 depolarization
3. reduced vagal tone
Factor/factors that can increase automaticity:
1. cardiac fiber stretch
2. beta adrenergic receptor blockade
3. injury currents
4. hypokalemia
Reduction of ventricular following rate in atrial fibrillation:
1. verapamil (Isoptin, Calan)
2. propranolol (Inderal)
3. quinidine
4. digoxin (Lanoxin, Lanoxicaps)
5. atropine
Increase sympathetic tone increases phase 4 depolarization and increases delayed afterdepolarizations and early afterdepolarization
1. true
2. false
Quinidine pharmacology:
1. increased threshold
2. increased automaticity
3. vagal inhibition (antimuscarinic)
4. shortening of the QT interval
5. cinchonism
Drug-induced lupus syndrome
1. quinidine gluconate (Quinaglute, Quinalan)
2. flecainide (Tambocor)
3. amiodarone (Cordarone)
4. procainamide (Procan SR, Pronestyl-SR)
5. metoprolol (Lopressor)
Termination of paroxysmal supraventricular tachycardia:
1. adenosine (Adenocard)
2. digoxin (Lanoxin, Lanoxicaps)
3. scopolamine
4. valsalva maneuver
5. esmolol (Brevibloc)
Reflex bradycardia:
1. bethanechol (Urecholine)
2. trimethaphan
3. adenosine (Adenocard)
4. esmolol (Brevibloc)
5. methoxamine (Vasoxyl)
Short-acting cardioselective beta adrenergic receptor antagonist:
1. metoprolol (Lopressor)
2. atenolol (Tenormin)
3. adenosine (Adenocard)
4. esmolol (Brevibloc)
5. labetalol (Trandate, Normodyne)
Associated with beta adrenergic receptor blockade with respect to cardiac conduction:
1. increased AV conduction time
2. increased AV nodal refractoriness
Factor/factors that predisposed to delayed afterdepolarizations:
1. decreased adrenergic activity
2. digitalis toxicity
3. hypocalcemia
Reentry is most common cardiac conduction abnormality leading to arrhythmias
1. true
2. false
Mechanism/mechanism of action of antiarrhythmic drugs:
1. suppression of initiation sites come i.e. reduced automaticity.
2. prevention of early or delayed afterdepolarizations
3. disrupting a reentrant pathway
Main action on the heart:
1. verapamil (Isoptin, Calan)
2. nifedipine (Procardia, Adalat)
3. diltiazem (Cardiazem)