A posterior hemiblock will cause which type of axis deviation?

A posterior hemiblock will cause which type of axis deviation?

• A. Left axis deviation
• B. No axis deviation
• C. Right axis deviation
• D. Superior axis deviation

Answer: (C)

A posterior hemiblock is a type of conduction block that specifically affects the posterior fascicle of the left bundle branch. When this block occurs, it can lead to a shift in the electrical axis of the heart. The unique aspect of posterior hemiblock is that it blocks the posterior fascicle which is responsible for conducting impulses to the inferior and posterior aspects of the left ventricle.

As a result, the left ventricle's depolarization is primarily altered, which tends to shift the overall electrical axis of the heart to the right. This manifests as a right axis deviation on an EKG.

In clinical practice, recognizing this type of deviation is essential for accurately diagnosing the underlying conduction disturbances and understanding their implications in terms of cardiac function and potential heart disease. Proper identification of axis deviations can provide critical insights into the patient's cardiac health and guide appropriate management.