|qRBBB with LAFBInstead of the rSR pattern (seen in RBBB), there is qRBBB pattern in V1 because the initial r wave has been knocked off by anterior wall myocardial infarction.|
RBBB causes delayed depolarisation of right Ventricle as depolarisation spreads across the septum (instead of the Right Bundle) taking longer than usual. This produces characteristic ECG changes described below in the diagnostic criteria. Left Ventricle depolarisation remains normal i.e normal early part of QRS complex.
- Broad QRS > 120 ms
- RSR’ pattern in V1-3 (‘M-shaped’ QRS complex) or a broad monophonic r wave or a qR complex
- Wide, slurred S wave in the lateral leads (I, aVL, V5-6
- Delayed intrinsicoid deflection time
|RBBB (Image from LIFTL)|
- Ischemic Heat Disease
- Acute Pulmonary HTN (PE)
- Chronic Pulmonary HTN (Cor Pulmonale)
- Valvular Heart Disease
- Degenerative Diseases of conduction system
- Congenital Heart Disease
- Overdose of Na Channel Blockers
- Transient and Rate Related
- Remember the qRBBB pattern morphology
- RBBB should never have any ST elevation
- When in doubt, do serial ECGs and screening bedside ECHO to look for RWMA
References and Further Reading:
- Mishra, V., Sinha, S. K., & Razi, M. (2016). Right Bundle Branch Block: A Masquerader in Acute Coronary Syndrome. North American Journal of Medical Sciences, 8(2), 121–122. http://doi.org/10.4103/1947-2714.177347
- 2. Widimsky P, Rohác F, Stásek J, Kala P, Rokyta R, Kuzmanov B, et al. Primary angioplasty in acute myocardial infarction with right bundle branch block: Should new onset right bundle branch block be added to future guidelines as an indication for reperfusion therapy? Eur Heart J. 2012;33:86–95.
- Ganesan S, Kannan K, Victor A, Selvan KT, Arun R, Majella JC, Kumar RS, Aravind A, Viswanathan N, District V. QRBBB in acute coronary syndrome: Does it matter in modern era? Angiographic correlation. Indian Heart Journal. 2015 Dec 1;67:S38.
- Wong CK, Stewart RA, Gao W, French JK, Raffel C, White HD. Prognostic differences between different types of bundle branch block during the early phase of acute myocardial infarction: Insights from the Hirulog and Early Reperfusion or Occlusion (HERO)-2 trial. Eur Heart J. 2006;27:21–8.