What happens to cardiac conduction with the use of sodium channel blockers?

Sodium channel blockers are known for their role in affecting cardiac conduction, primarily through the modulation of sodium ion flow across cell membranes. By blocking sodium channels, these medications reduce the influx of sodium ions during the depolarization phase of the cardiac action potential. This action leads to a decrease in conduction velocity due to the slower depolarization and propagation of electrical impulses through the myocardium.

It's important to note that while sodium channel blockers generally decrease conduction velocity, there are situations where they can also help stabilize cardiac rhythm, particularly in certain types of arrhythmias. This stabilization can lead to a normalization of conduction in specific contexts, creating a scenario where the overall conduction velocity might be altered in unexpected ways. Therefore, the overall effect can indeed be described as a decrease or, in some cases, an increase in conduction velocity, based on their action and the state of the cardiac tissue they are affecting.

This nuanced understanding reflects why the answer indicating that sodium channel blockers can decrease or increase conduction velocity is accurate, as it captures the dual potential outcomes of their effects on cardiac conduction.