However, according to the American Heart Association/American College of Cardiology Foundation/Heart Rhythm Foundation (AHA/ACCF/HRS) it is defined by the following finding in adults:

QRS wave duration between 110 and 120 ms.
rsr, rsR, or rSR in leads V1 or V2. S wave of longer duration than R wave or greater than 40 ms in leads I and V6. Normal R wave peak time in both V5 and V6, but greater than 50 ms in V1.The first three criteria are needed for diagnosis. The fourth is needed when a pure dominant R waver is present on V1. Causes
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. In addition, a right bundle branch block may also result from Brugada syndrome, pulmonary embolism,  rheumatic heart disease, myocarditis, cardiomyopathy, or hypertension.Causes for incomplete right bundle branch block are exercise-induced right ventricular remodeling, increased RV free wall thickness, especially in athletes due to prolonged endurance exercise. Diagnosis
The criteria to diagnose a right bundle branch block on the electrocardiogram:

The heart rhythm must originate above the ventricles (i.e., sinoatrial node, atria or atrioventricular node) to activate the conduction system at the correct point. The QRS duration must be more than 100 ms (incomplete block) or more than 120 ms (complete block). There should be a terminal R wave in lead V1 (often called "R prime," and denoted by R, rR, rsR, rSR, or qR).
In the series The Adventures of Shirley Holmes, one episode featured a princess who was the heir to the throne of her country and feared that her stepmother wanted to have her assassinated as her own son was next in line after her stepdaughter. The episode concludes the revelation that her stepmother actually wanted her stepdaughter to inherit the throne and had attempted to thwart actual assassins who did not want a woman to rule their country. In Sofia the First, Sofias mother Miranda became stepmother to Prince James and Princess Amber, she acknowledged there werent many tales featuring loving and kind stepmothers. This is another example of a well-blended family. Classical Literature
Greek
Alcestis (play)
438 BCE: The dying biological mother requests that her husband not remarry, for fear of her children being mistreated by a stepmother. Hippolytus
428 BCE: The stepmother commits suicide to prevent herself from following through on her lust for her stepson and leaves a note falsely claiming that the stepson had raped her. == References ==