Normal Chest X-ray
 


Left Atrial Dilatation 
Prominence of left atrial appendage (straightening or convex) with double atrial shadow
  
Right Atrial Dilation 
Right boarder of the heart projecting into the right lower lung field.
  
Electrocardiogram Results :~ 
a. An electrocardiographic criterion of left atrial enlargement is a 
P wave (>0,12sec) that is too wide  or inverted in lead II and V1 :  
P mitrale
*normal PR interval 0,12-0,20 sec 


b. An electrocardiographic criterion of right atrial enlargement is a 
P wave (>0,28sec) that is high amplitude in lead II and V1 : P pulmonal


c. An electrocardiographic criterion of biatrial enlargement is a 
P wave that is too tall and too wide in lead II.
 


The conclusion for atrial investigations :)~

Left Atrial Enlargement (LAE)
Right Atrial Enlargement (RAE)