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Right bundle branch block, RBBB

See brief interpretation of 12 lead EKG above

Right bundle branch block (RBBB) is best seen in V1 as this lead is “looking” at the right side of the heart. Recall the electrical conduction system of the heart – what happens with the electrical conduction if the right bundle branch is blocked?

As the right bundle branch is blocked the right ventricle is depolarized through slower conducting pathways from the left ventricle. The left ventricle depolarizes in a normal way as the left bundle branch is unaffected. Corresponding to this delayed activation of the right ventricle the QRS is prolonged ≥ 0.12 sec. on the EKG. Also in lead V1 the latter part of the QRS complex is abnormal with an extra R wave in lead V1 due to the late activation of the right ventricle resulting in a typical rSR’ pattern. In lead I, V5 or V6 a late wide/slurred S wave can be seen (see 12 lead EKG above). Finally there might be depression of the ST segment or T wave inversion due to repolarisation changes.

detail rbbb Right bundle branch block, RBBB

For practical purposes intuitively suspect a right bundle branch block, when a “M” configuration of the QRS complex in lead V1 is present in an apparently otherwise normal EKG (the rSR’ configuration resembles the character M).

Right bundle branch block is common and the incidence increases with age. It is often seen in otherwise healthy individuals. However attention should in particular be given when RBBB is seen in combination with other conduction defects, seizures and after myocardial infarction.

– Mathias

{ 3 comments… read them below or add one }

mavinashan March 26, 2012 at 3:54 am

i would like to know how to differentiate abnormalities on a 12 lead ecg and on which lead to see.

MUSTAFA KÖKKIZ July 30, 2012 at 3:51 pm


Dr. George DeLand September 21, 2012 at 1:59 am

would a lead v1 tracing of rSr’s’ with a qrs duration of 92 milliseconds also suggest a RBBB in a 10 yr old who is overweight?

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