Purkinje fibres are the terminal portions of the conduction system of the heart. The electrical signals reach the lower chambers of the heart (ventricles) through the conduction bundle known as the bundle of His. The bundle of His divides into the left and right bundle branches which go to the respective ventricles. The left bundle branch further subdivides into two divisions (anteriror and posterior – to the front and back of the left ventricle). The bundle branches further divide into multiple small branches which finally connect with the heart muscle fibres to activate them in a periodic fashion during each heart beat. These terminal branches of the conduction system are known as Purkinje fibres.