right bundle branch
Summary
The right bundle branch is part of the cardiac conduction system that carries electrical impulses from the bundle of His to the right ventricle. Right bundle branch block (RBBB) causes delayed right ventricular depolarization, resulting in a characteristic wide QRS complex with an RSR' pattern in V1-V2.
Detail
The right bundle branch is a fascicle of specialized cardiac conduction tissue that originates from the bundle of His and travels down the right side of the interventricular septum to innervate the right ventricle. It's typically a single, thin strand compared to the left bundle branch system. Right bundle branch block (RBBB) occurs when conduction through this pathway is delayed or blocked, causing the right ventricle to depolarize after the left ventricle. This results in a QRS duration ≥120ms with characteristic ECG findings: RSR' pattern in V1-V2 (rabbit ears), wide S waves in leads I and V6, and secondary T-wave inversions in right precordial leads. RBBB can be complete or incomplete (<120ms QRS). Causes include right heart strain (pulmonary embolism, pulmonary hypertension), structural heart disease, myocardial infarction, or can be idiopathic in healthy individuals. Unlike LBBB, isolated RBBB in asymptomatic patients often has no clinical significance and doesn't typically indicate underlying heart disease.
Sources
- Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine
- ECG Interpretation Made Incredibly Easy
- First Aid for the USMLE Step 1
- UpToDate: Bundle Branch Blocks
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