What is the most common heart abnormality indicated by RBBB on an EKG?

The most common heart abnormality indicated by a right bundle branch block (RBBB) on an electrocardiogram (EKG) is a heart block. RBBB occurs when there is a delay or blockage along the electrical pathways that conduct impulses to the right side of the heart.

Heart block can manifest in different degrees, and while RBBB itself does not definitively indicate a complete heart block or damage, it is often associated with underlying conditions that involve abnormalities in the cardiac conduction system. Identification of RBBB prompts further evaluation to determine whether it is isolated or part of a more extensive conduction system disease, often seen in patients with other cardiovascular conditions.

In relation to the other choices, myocardial infarction could result in various EKG changes, including those leading to RBBB, but it is not the direct outcome and more commonly presents with other significant EKG markers. Coronary artery disease may be present in patients with RBBB, yet it does not directly indicate this specific abnormality. Heart failure can be associated with a range of EKG findings but is not a direct cause of RBBB compared to conduction abnormalities leading to heart block. Therefore, identifying RBBB strongly correlates with conduction issues primarily seen in heart block scenarios.