2.5 mm.o It is easy to explain why it not getting wide than why it is gettingtaller.The atrial vector has two components.The initial RA vector, is directed anteriorly. The main reason is due to the anatomical proximity of RA to the chest wall. Further the atrial electrical dp/dt is fast, so the slope of forward limb is steep. Any R.4 voltage increase is easily picked up by the chest leads.LAE can not produce tall P waveo The left atrial vector which follows RA vector is mainly directed posteriorly and hence inscribe a descending limb ofP wave.o This causes the P terminal force.o So the direction of vector forces and the anatomical locality' make a tall and positive P deflection highly improbable in LAE.">