What does a bundle branch block appear like on an EKG?

What does a bundle branch block appear like on an EKG?

• A. A narrow and tall QRS complex
• B. Two distinct R peaks with no other waves between
• C. Normal appearing QRS complexes
• D. An absence of QRS complexes

Answer: (B)

A bundle branch block on an EKG is characterized by two distinct R peaks, which results in a widened QRS complex. This occurs due to the delayed conduction of electrical impulses in either the left or right bundle branch of the heart. The appearance of two distinct peaks indicates that the depolarization of the ventricles is taking longer than usual because one bundle branch is blocked, thus showing an altered pattern.

In contrast to this correct description, other possibilities such as a narrow and tall QRS complex would typically indicate a different issue, potentially related to conditions like ventricular hypertrophy, where the ventricles are enlarged and result in a different appearance on the EKG. Normal appearing QRS complexes indicate normal conduction through the heart's electrical system, ruling out the presence of a bundle branch block. An absence of QRS complexes suggests a complete failure of depolarization, which is not the case with bundle branch block, where QRS complexes are present but altered in shape.