Therefore, if abnormalities are detected on the physical exam, further testing should be done to exclude heart disease.

However, according to the American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society (AHA/ACCF/HRS) it is defined by the following finding in adults: The first three criteria are needed for diagnosis.

[3] Common causes include normal variation, changes in bundle branch structure - such as mechanical stretching, chest trauma, right ventricular hypertrophy or strain, congenital heart disease such as atrial septal defect, and ischemic heart disease.

[7] Causes for incomplete right bundle branch block (IRBBB) often involve exercise-induced right ventricular remodeling, increased right ventricular (RV) free wall thickness, especially in athletes due to prolonged endurance exercise.

[10] Prevalence of RBBB increases with age due to changes in the heart's conduction system.