Anesthesia Pharmacology: Antiarrhythmic Drugs Practice Questions

Factors that reduce membrane resting potential:
1. ischemic cells damage
2. hyperkalemia
3. sodium pump blockade
4. B & C
5. A, B & C
Activation status sodium channels that -55 mV:
1. inactivated
2. activated
Principal ion responsible for action potentials in specialized conducting SA nodal and AV nodal tissues:
1. sodium
2. calcium
3. potassium
Mechanism(s) of arrhythmia development:
1. disturbances of impulse formation
2. abnormal impulse propagation
3. both
4. neither
Mechanism(s) associated with many tachyarrhythmias:
1. reduced automaticity
2. triggered automaticity
3. reentry
4. B & C
5. A & B
Factor(s) predisposing to delayed afterdepolarizations (DAD):
1. excessive adrenergic activity
2. low intracellular potassium
3. bradycardia
4. certain drugs -- including some antiarrhythmics
5. all of the above
Triggered automaticity: associated with significant action potential duration prolongation
1. delayed afterdepolarization
2. early afterdepolarization
3. both
4. neither
Torsades de Pointes:
1. supraventricular arrhythmia
2. associated with shortened QT intervals
3. possibly induced by early afterdepolarizations
4. A & B
5. B & C
Most common cardiac conduction abnormality leading to arrhythmias:
1. delayed afterdepolarization
2. early afterdepolarization
3. reentry
4. each mechanism equally likely
Electrophysiological basis for increasing heart rate:
1. increased slope of phase 4 depolarization
2. decreased slope of phase 4 depolarization
Factors that increase slope of phase 4 depolarization:
1. injury currents
2. acidosis
3. beta adrenergic receptor blockade
4. A & B
5. A, B & C
More likely to decrease the slope of phase 4 depolarization:
1. edrophonium (Tensilon)
2. atropine
3. isoproterenol (Isuprel)
All cardiac cells may show pacemaker activity:
1. true
2. false
Mechanism(s) of antiarrhythmic drug action:
1. disrupting re-entrant pathways
2. preventing delayed afterdepolarizations
3. suppressing automaticity
4. A & B
5. A, B & C