There is now a terminal vector (3) directed superiorly and to the right with an axis of -150 degrees (or +210 degrees). This represents the electrical forces associated with the development of right bundle branch block. The initial (1) and main (2) vectors remain similar to those in the tracing recorded prior to the development of the right bundle branch block (see previous page). The loop encompassing these spatial vectors is inscribed in a counter-clockwise direction.