7.21
Code 7.21 — Minnesota Code 7-2-1: complete right bundle branch block. The Minnesota Code assigns 7-2-1 when the QRS duration is 0.12 s (120 ms) or more in a majority of beats in the limb leads and the right precordial leads (V1 or V2) show an R′ wave (rsR′, rSR′ or a broad R); a broad terminal S wave in I and V6 usually accompanies it. The right ventricle is activated late, after the left. Unlike LBBB, RBBB does not prevent the coding of Q waves for myocardial infarction.
Related Minnesota codes
| Code | Meaning |
|---|---|
| 7-2-1 | Complete RBBB |
| 7-2-2 | Intermittent RBBB |
| 7-3 | Incomplete RBBB (QRS < 120 ms with R′ in V1/V2) |
| 7-8 | RBBB combined with left anterior fascicular block (bifascicular block) |
Clinical significance
Isolated RBBB is found in a few percent of older adults and often has no clinical consequences. It becomes more significant when it is new, when it is combined with left anterior or posterior fascicular block or a prolonged PR interval, or when heart or lung disease is present. A new RBBB with sudden breathlessness may indicate pulmonary embolism; with chest pain, it may indicate an acute infarction.
if RBBB appears together with chest pain, sudden breathlessness, fainting or a very slow pulse.
References
- Prineas RJ, Crow RS, Zhang ZM. The Minnesota Code Manual of Electrocardiographic Findings. 2nd ed. London: Springer; 2010. doi:10.1007/978-1-84882-778-3
- 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. ECG findings must be interpreted by a physician together with symptoms and other tests.
Published on 14 May 2019