What is RBBB

The full terms of RBBB is Right Bundle Branch Block

ECG Criteria

• RSR—in V1 and V2 (M pattern).
• QRS—wide, >0.12 second (3 small squares).

Causes of RBBB

• Normal variant (common).
• Coronary artery disease- acute myocardial infarction.
• Atrial septal defect (ASD).
• Right ventricular hypertrophy.
• Chronic cor pulmonale.
• Pulmonary embolism.
• Cardiomyopathy.
• Conduction system fibrosis.
Fascicular Block (Hemiblock)
Left bundle divides into anterior and posterior fascicles.
• Anterior fascicle spreads in anterior and superior part of left ventricle.
• Posterior fascicle spreads in posterior and inferior part of left ventricle.
• Fascicular block is diagnosed by looking at the axis deviation.
Fascicular block are of two types:
• RBBB with left anterior hemiblock (block in anterior fascicle).
• RBBB with left posterior hemiblock (block in posterior fascicle).
ECG in RBBB with Left Anterior Hemiblock
• RBBB with left axis deviation.
ECG in RBBB with Left Posterior Hemiblock
• RBBB with right axis deviation.