Right bundle branch block electrocardiogram
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]
Overview
Criteria for complete right bundle branch block include: a QRS duration of > .12 seconds, an rSR' pattern with a wide terminal R wave in V1 and a qRS complex with a wide S wave in V6.
Electrocardiogram
- The heart rhythm must be supraventricular in origin
- The QRS axis can be either normal, or right or left axis deviation may be present.
- The QRS duration must be = or > 120 ms
- For complete RBBB, the patient's age must be taken into account to determine if the duration of the QRS complex is prolonged for the patient's age.
- Maximum QRS durations are 0.07 s for newborns <6 days, 0.08 s for patients aged 1 week to 7 years, and 0.09 s for patients aged 7-15 years.
- For complete RBBB, the patient's age must be taken into account to determine if the duration of the QRS complex is prolonged for the patient's age.
- There should be a terminal R wave in lead V1-V3R (e.g., R, rR', rsR', rSR' or qR')
- This pattern is present because the initial R wave represents septal activation, the S wave represents left ventricular activation, and the R' represents activation of the right ventricle from the septum and left ventricle.
- There should be a slurred S wave in leads I and V6. This represent left ventricular activation.
- Because transmission of the electrical impulse through the left bundle is normal, this results in normal depolarization of the septum and the left ventricle. As a result, there is an initial R wave in lead I and V1 and the Q wave in V6.
The T wave should be deflected opposite the terminal deflection of the QRS complex. This is known as appropriate T wave discordance with bundle branch block. A concordant T wave may suggest ischemia or myocardial infarction.
Below is an electrocardiogram showing the main characteristics of right bundle branch block on lead V1.
Copyleft image obtained courtesy of ECGpedia, http://en.ecgpedia.org/wiki/Main_Page
The rhythm is sinus. The QRS is wide (>120ms.) and the axis is markedly negative. There are small R waves in the inferior leads. The recording shows a right bundle branch block and a left anterior fasicular block.
Copyleft image obtained courtesy of ECGpedia, http://en.ecgpedia.org/wiki/Main_Page
- For EKG examples of right bundle branch block click here.