Right bundle branch block

Right bundle branch block [*]

• Left bundle depolarizes normally
1. Initial QRS is normal
• Right ventricular depolarization is delayed
1. Late portions of QRS are abnormal
2. Late R wave in right precordial leads
3. Wide, slurred S wave in left precordial leads
• T waves are abnormal due to abnormal depolarization induced changes in repolarization

Diagnostic criteria for RBBB [*]

• QRS 0.12 seconds or greater
• Secondary R’ in lead V1 or V2
• Wide, slurred S wave in leads I, V5 and V6
• Secondary inversion of T waves in right precordial leads
• Causes of RBBB
1. Rheumatic heart disease
2. Right ventricular hypertrophy
3. Myocardial disease
4. Ischemic heart disease
5. Degeneration of the conduction system
6. Pulmonary embolism
7. Congenital diseases such as atrial septal defects