What are causes of right bundle branch block?

Many. It can be congenital. It is often present with right ventricular or right atrial pressure or volume overload such as occurs with atrial or ventricular septal defect. Hypertension causes many cases. Pulmonary artery hypertension, as occurs in advanced lung disease or pulmonary embolism, can cause it. Finally, it's present in many healthy people for no reason at all.
Variety of things. Right bundle branch block is due to a conduction problem within the electrical system of the heart. This can be an isolated electrical problem or a reflection of structural heart disease.

Related Questions

I have an incomplete right bundle branch block is it dangerous nd can cause a cardiac arrest?

Irbbb usually safe. Irbbb is usually an ECG anomaly that may speak of some right sided enlargement or strain (can occur in atrial septal defect or in pulmonary processes with right heart strain ). It can also occur innocuously and unrelated to cardiac structural changes. It does not typically imply impending conduction system collapse and is not a predictor for cardiac arrest or sudden cardiac death. Read more...
No and no. By itself a rbbb is not a problem unless it is associated with structural heart disease. An echo would answer the question. Read more...