A drug that serves as a sodium channel blocker will have the greatest effect on which phase of ion exchange in the normal, fast-potential cardiac cell?
A) 0
B) 1
C) 2
D) 3

Question

Quizplus · Accepted Answer

During phase 0 of the cardiac action potential, there is a rapid influx of sodium ions into the cell through voltage-gated sodium channels. Therefore, a drug that serves as a sodium channel blocker will have the greatest effect on this phase, as it will inhibit the influx of sodium ions and thus impair depolarization.

A Drug That Serves as a Sodium Channel Blocker Will