What is the effect of a complete bundle branch block on ventricular contraction?

What is the effect of a complete bundle branch block on ventricular contraction?

• A. Increases the heart rate
• B. Delays ventricular contraction
• C. Causes arrhythmias
• D. Reduces overall stroke volume

Answer: (B)

A complete bundle branch block disrupts the normal conduction of electrical impulses through the heart. This blockage occurs in one of the bundle branches that carry impulses to either the left or right ventricle. As a result, the affected ventricle receives the electrical signal later than the other ventricle.

This delayed conduction leads to asynchronous contractions of the ventricles, where one ventricle contracts before the other. This delay in the ventricular contraction affects the overall efficiency of the heart's pumping action, as coordinated contractions are essential for optimal blood flow. By causing a delay in ventricular contraction, a complete bundle branch block can consequently alter the timing of the heart's pumping cycle but not necessarily increase the heart rate or directly induce arrhythmias.

Given that the heart's ability to effectively pump blood is compromised due to the delayed contraction, this also can influence factors such as stroke volume, but the primary effect is the delay in the contraction itself.