Right bundle branch block - Conduction disturbances

Right bundle branch block

Definition

Block to the right branch of the bundle of His, which normally facilitates transmission of impulses to the right ventricle.

Aetiology/pathophysiology

Right bundle branch block is often due to a congenital abnormality of little significance, but may be associated with atrial septal defects. In older patients it is commonly caused by ischaemic heart disease, fibrosis of the bundles or pulmonary disease. Acute onset right bundle branch block may be associated with pulmonary embolism or a right ventricular infarct.

Clinical features

Right bundle branch block is asymptomatic and is often an incidental finding. There is widened splitting of the heart sounds with the pulmonary sound occurring later than normal.

Investigations

The characteristic RsR’ is seen best in lead V1 and a late S wave is seen in V6. Complete block of the bundle results in a QRS complex of greater than 0.12 seconds (see Fig. 2.14).

Complications

Syncope due to intermittent complete heart block.

Management

Treatment is not necessary.

Prognosis

Isolated right bundle branch block, particularly in a young person is generally benign. Concomitant left or severe right axis deviation may indicate block in one of the fascicles of the left bundle, which can occur as a pre-cursor to complete heart block which in turn carries a worse prognosis.

Management

Treatment is not necessary.

Prognosis

Isolated right bundle branch block, particularly in a young person is generally benign. Concomitant left or severe right axis deviation may indicate block in one of the fascicles of the left bundle, which can occur as a pre-cursor to complete heart block which in turn carries a worse prognosis.