Deck 22: Antiarrhythmic Drugs

Question 1

The class III drug amiodarone:

A) Delays influx of sodium into the myocyte
B) Blocks several potassium channels, prolonging the action potential
C) Delays influx of calcium into the myocyte
D) Has beta adrenergic receptor blockade properties
E) All of the above are correct

Answer 1

All of the above are correct

Question 2

The mechanism of action of class III antiarrhythmic drugs is:

A) Sodium channel blocker
B) Potassium channel blocker
C) Beta adrenergic blocker
D) Calcium channel blocker
E) Local anesthetic action

Answer 2

Potassium channel blocker

Question 3

The action potential of a myocardial pacemaker cell differs from that of the non-pacemaker cell in that:

A) The resting membrane potential is more negative in the pacemaker cells.
B) The depolarization is faster in the pacemaker cell.
C) Ca⁺⁺ channels do not play a significant role in the pacemaker cell action potentials.
D) Potassium channels conductance is primary for initiation of the action potential in pacemaker cells.
E) The pacemaker cell action potential depolarization is initiated by the influx of calcium.

Answer 3

The pacemaker cell action potential depolarization is initiated by the influx of calcium.