You perform an ECG in a 45 year old woman that has presented to you with left sided chest pain.

 You perform an ECG in a 45 year old woman that has presented to you with left sided chest pain.

Her ECG Is given below :

1 . What are the findings in the ECG ?

There is a qR complex in lead V1.

There is "Appropriate discordance " which refers to abnormal depolarisation being followed by abnormal repolarisation, which appears discordant to the preceding QRS complex.

In RBBB, this manifests as ST depression and/or T-wave inversion in leads V1-3.

2 . What is the most likely diagnosis?

Right bundle branch block.

3 . What are the causes of this condition?

Causes of Right Bundle Branch Block :

Right ventricular hypertrophy / cor pulmonale

Pulmonary embolus

Ischaemic heart disease

Rheumatic heart disease

Congenital heart disease (e.g. atrial septal defect)

Myocarditis

Cardiomyopathy

Lenègre-Lev disease: primary degenerative disease (fibrosis) of the conducting system.

4. What is the pathiphysiology of this disease.

In normal cardiac conduction, impulses travel equally down the left and right bundles, with the septum activated from left to right and the formation of small Q waves in lateral leads

In RBBB, the left ventricle is activated normally, thus the early part of the QRS complex correlating to septal depolarisation is unchanged.

There is delayed activation of the right ventricle as depolarisation originates from the left ventricle across the septum. This produces a secondary R wave (R’) in the precordial leads, and a wide, slurred S wave in lateral leads.

Normal activation of the left ventricle means that cardiac axis remains normal in isolated RBBB