I45.1

Right bundle branch block (I45.1): rsR′ pattern, causes, significance and differentiation from Brugada syndrome.

Right bundle branch block (RBBB, ICD-10 I45.1) is a block of conduction in the right bundle branch. The left ventricle is activated normally through the left bundle, but the right ventricle is activated late, through the muscle from the left side. On the ECG this produces a wide QRS (at least 120 ms in complete block) with a characteristic rsR′ pattern ("M shape") in V1–V2 and a broad S wave in leads I and V6. Unlike LBBB, isolated RBBB is often found in healthy people and usually has little significance on its own, but it can also accompany diseases of the right heart and lungs.

ICD-10 I45.1Bundle branch blockRight ventricle

QRS duration (complete)≥ 120 ms

Incomplete RBBBQRS 110–119 ms

V1–V2rsR′ pattern

I, V6broad, slurred S wave

Figure 1. Left: normal QRS in V1 (rS). Right: complete RBBB — rsR′ pattern with QRS of 120 ms or more and secondary T-wave inversion.

Causes

Found in healthy people, more often with increasing age
Right heart strain: acute pulmonary embolism, pulmonary hypertension, chronic lung disease
Congenital heart disease: atrial septal defect, after surgery for tetralogy of Fallot
Coronary artery disease, cardiomyopathies, myocarditis, Chagas disease, degenerative conduction disease
After right heart catheterisation (usually temporary)

Significance and management

Isolated RBBB without symptoms or heart disease needs no treatment. A new RBBB with sudden breathlessness or chest pain may indicate pulmonary embolism or myocardial infarction. The ECG must be distinguished from Brugada syndrome, which has a similar-looking pattern with ST elevation in V1–V2 and carries a risk of sudden death. RBBB combined with left anterior or posterior fascicular block (bifascicular block) requires attention to fainting, which may indicate intermittent complete heart block.

When to see a doctor

Fainting, palpitations, breathlessness or chest pain in a person with RBBB, or a family history of sudden death, need cardiological assessment.

References

Surawicz B, Childers R, Deal BJ, Gettes LS. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances. Circulation. 2009;119(10):e235–e240. doi:10.1161/CIRCULATIONAHA.108.191095
Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay. Circulation. 2019;140(8):e382–e482. doi:10.1161/CIR.0000000000000628

This article is for general information and does not replace a consultation with a doctor. Diagnosis and treatment must be decided by a physician on the basis of symptoms, examination and tests.

Published on 24 March 2019