EKG

What does EKG actually stand for?
Electrocardiography.
EKG is an interpretation of the electrical activity of your heart over a certain period of time!
During this test, the doctors (or whoever is doing it) takes electrodes and places them on parts of your body such as your arms, legs, head, and stomach. Then, the recordings from the electrodes goes into a graph that is shown below!

The P Wave is the first wave on the EKG. It represents the span of electrical impulse through the atrial musculature. This would be activation or depolarization. 

The normal duration for the P wave is .11 seconds, 3mm in length, and it is positive.

Then comes the P-R interval. This is measured from the beginning of the P wave through the beginning of the QRS wave. What is happening here is the EKG is measuring the time it takes the heart to travel from the SA node all the way to the ventricular muscle fibers. The normal duration of this ranges from .12 - .2 seconds and is faster when the heart is beating faster. 

Probably the most important and complex of the EKG would be the QRS Wave. It represents the spread of impulse through the ventricular muscle or depolarization. If the first deflection if negative, it is then labeled the Q wave. The first positive wave is labeled the R wave (doesn't matter if it follows the Q wave). Then the second negative duration detected following the Q wave is labeled the S wave. This duration should not last longer then .05-.10 seconds.

The S-T Segment comes next and it always follows the QRS segments. This begins at the J(junction) point. The point that is measured is the elevation or depression and the shape is also examined. 

Last comes the T Wave! This represents the period of time it takes for the recovery of the ventricles. During this wave the direction, shape, and height is examined. 

This can be used for many things! Such as to detect abnormalities in the heart. If certain waves are longer then normal or abnormally shaped, doctors can examine the EKG to figure out exactly what the heart is doing that it's not supposed to be doing!

We actually had the chance to do this in class! Here is an example of one of the EKG's in the group that I worked with!