What is the effect of AV blocks on conduction signals?

What is the effect of AV blocks on conduction signals?

• A. They speed up conduction from the atria to the ventricles
• B. They have no effect on conduction signals
• C. They slow or prevent conduction from the atria to the ventricles
• D. They only affect ventricular depolarization

Answer: (C)

AV blocks are characterized by an interruption or delay in the conduction pathways between the atria and ventricles, specifically at the atrioventricular (AV) node. In cases of AV block, the normal transmission of electrical impulses from the atria to the ventricles is disrupted. This can result in a slower heart rate and may lead to ventricular depolarization occurring either after a longer delay or not at all, depending on the severity of the block.

The presence of AV blocks can manifest as varying degrees of impairment in conduction. For instance, in first-degree AV block, there is a prolonged PR interval but all impulses do reach the ventricles. In second-degree AV block, some impulses fail to conduct to the ventricles, and in third-degree AV block, there is a complete failure of conduction between the atria and ventricles.

This slowing or prevention of conduction leads to potential symptoms such as bradycardia, syncope, or other complications, which showcases the importance of recognizing and understanding the nature of AV blocks. Therefore, they significantly impact the conduction of signals between the atria and ventricles.