ECG changes

 P mitrale-

seen in left atrial enlargement

 broad p wave occupying >0. 11 sec in lead 2 or biphasic in V1

P pulmonale -

 seen in right atrial enlargement 

Tall p wave > 2.5 mm in lead 2

LVH - 

1.sum of s waves in lead V1 and sum of R wave in lead V6 more than 35 mm

2.S wave in V1 20mm or more in depth

3.R wave in V6 more than 25 mm

Right axis deviation

P wave negative in in lead 1 and positive in lead 3

Left axis deviation

P wave  positive in lead 1 and negative in lead 3

Normal axis 

P wave positive in lead 1 and positive in lead 3