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