Complete Right Bundle Branch Block vs Complete Left Bundle Branch Block: clinical and ECG differences
Side-by-side comparison of Complete Right Bundle Branch Block and Complete Left Bundle Branch Block according to the MioAtlas 3D cardiac simulator model.
Findings by layer and diagnostic parameters
| Layer / Finding | Complete Right Bundle Branch Block | Complete Left Bundle Branch Block |
|---|---|---|
| Clinical summary |
The right ventricle does not receive impulse via the right bundle branch and activates late, cell-to-cell across the septum from the left ventricle. QRS duration ≥ 120 ms with typical rSR' ('rabbit ears') pattern in V1-V2 and wide, slurred S wave in I, aVL, and V6. Secondary repolarization changes in right precordial leads. |
Complete block in the main trunk of the left bundle branch. Ventricular activation is drastically altered: the septum activates from right to left, and the left ventricle activates late and slowly. Wide QRS (≥ 120 ms), broad notched or slurred R waves in I, aVL, V5-V6, and deep QS or rS in V1-V2. Normal septal q waves in lateral leads disappear. |
| Heart rate |
75 bpm (min: 60, max: 100) |
75 bpm (min: 60, max: 100) |
| QRS duration |
135 ms |
150 ms |
| Mechanism |
bloqueo |
bloqueo |
| AV conduction |
1:1 |
1:1 |
| Key leads |
V1, V2, I, aVL, V6 |
V1, V2, V3, I, aVL, V5, V6 |
Sources and bibliographic references
Complete Right Bundle Branch Block
- Surawicz B, Childers R, Deal BJ, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: Part III: Intraventricular conduction disturbances . Circulation (2009) . DOI: 10.1161/CIRCULATIONAHA.108.191095
- Anderson RH, Yanni J, Boyett MR, Chandler NJ, Dobrzynski H. The anatomy of the cardiac conduction system . Clin Anat (2009) . DOI: 10.1002/ca.20700
- Kligfield P, Gettes LS, Bailey JJ, et al. Recommendations for the standardization and interpretation of the electrocardiogram: Part I: The electrocardiogram and its technology . Circulation (2007) . DOI: 10.1161/CIRCULATIONAHA.106.180200
Complete Left Bundle Branch Block
- Surawicz B, Childers R, Deal BJ, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: Part III: Intraventricular conduction disturbances . Circulation (2009) . DOI: 10.1161/CIRCULATIONAHA.108.191095
- Anderson RH, Yanni J, Boyett MR, Chandler NJ, Dobrzynski H. The anatomy of the cardiac conduction system . Clin Anat (2009) . DOI: 10.1002/ca.20700
- Kligfield P, Gettes LS, Bailey JJ, et al. Recommendations for the standardization and interpretation of the electrocardiogram: Part I: The electrocardiogram and its technology . Circulation (2007) . DOI: 10.1161/CIRCULATIONAHA.106.180200