Now that we understand what a PQRST is, the anatomy function that occurs to produce each letter, and some actual rhythms, let's try to understand an EKG and what leads affect what part of the heart.  On a 12-lead EKG, there are 6 limb leads which include 3 standard leads and 3 augmented leads. The 3 standard leads are: Lead I, Lead II, and Lead III by placing 2 electrodes, one on each arm and 2 electrodes, one on each leg.  The 3 augmented leads are somewhat different.  Any of the three leads can be positive and the other two negative with their average serving as the negative electrode or common ground.  Lead AVL, Lead AVR, and Lead AVF.  Lead AVL is created with left arm positive and the other limb leads negative, lead AVR is created with right arm positive and the other limb leads negative, and AVF is created with the legs being positive and the other limb leads negative.   There are also 6 precordial or chest leads arranged across the chest in a horizontal plane.  They are: V1, V2, V3, V4, V5, and V6 and are placed in specific areas on the chest.  V1is placed 4th intercostal space (ICS) to the right of the sternum, V2 placed 4ICS to the left of the sternum, V3 between V2 and V4, V4 placed 5ICS at midclavicular line, V5 placed between V4 and V6, and V6 placed 5ICS at the midaxillary line.  I understand this is a lot of information but please watch the video and you will understand better.  When the video is finished, please try on your own to mark the areas where the leads should be placed.  We will continue the 12-lead EKG in the next session.  If you have any questions please feel free to ask Marna!