Anesthesiology and Intensive Care

    In left bundle branch block there is a delay or blockage of conduction in the main left bundle  branch. This affects the normal depolarisation in the ventricles.     In left bundle branch block, the impulse begins in the SA node and depolarises the atria, then  travels through the AV node to the left and right bundle branches. On finding the left bundle branch  blocked, the impulse travels down the right bundle branch.