Left bundle branch block

What it is

Left bundle branch block is one of the bundle branch blocks. It is when the left bundle-branch is unable to conduct impulses to the left ventricle. The right bundle-branch therefore depolarizes the right ventricle first, then the impulse travels to the left ventricle causing it to depolarize, so the ventricles depolarize consecutively rather than simultaneously. Right bundle-branch block runs the other way: the right bundle-branch is unable to conduct impulses to the right ventricle, so the left bundle-branch depolarizes the left ventricle first and the impulse then travels to the right ventricle.