Page 192 - Critical Care Nursing Demystified

Chapter 4 CARE OF THE PATIENT WITH CRITICAL CARDIAC RHY THM DISTURBANCE NEEDS 177

FIGURE 4–5 • Rhythm strip.

can get a rough estimate using this method of what the rate is which will help
identify the heart’s pacemaker. This example is slightly on the tachycardic side
with a rate of 100. In the above rhythm strip the number of P waves in a
6-second strip is 10; so 10 times 10 = 100. So the atrial rate is 100.

Step Two: Rate—Counting the Ventricular Rate

You can use the same method as above, but this time count the number of QRS
complexes in a 6-second strip. There are more complicated methods, but for now,
let us stick with simple. In the rhythm strip above, the number of QRSs is 10, so
10 times 10 = 100. Okay, there were a lot of similarities in the last two, as you will Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
see in the next two steps. With a rate of 100, the nurse can identify the location of
the pacemaker, which is in the SA node as its natural rate is between 60 and 100.

Step Three: Rhythm—Determine the Atrial Rhythm

Determining the rhythm means you need to use some type of measuring tool.
You can use a blank piece of paper to make marks OR you can use a pair of
ECG calipers, which is a very accurate tool to measure tiny features from elec-
trical stimulation of the heart.
If you are using a blank piece of paper, place it underneath the ECG rhythm
strip along the isoelectric lines of the rhythm. Place a tiny mark at the beginning
of the P wave on the blank paper and another one at the P wave of the next
heartbeat. Then move the marks to the next P wave in the strip; this is some-
times called the P-to-P interval. It is also called “Marching out the P waves!” Do
they all come regularly? If so, your rhythm is regular.
Now, if you are fortunate enough to have a pair of calipers, take the left caliper
point and place it firmly at the beginning of the P wave and place the right caliper
point or tip at the beginning of next P wave. That is right, now you are right on
top of the ECG paper. Now lift the calipers and compare the distance between
each P wave. If the P waves all track out evenly from one caliper tip to the next,
the rhythm is regular. The atrial rhythm in Figure 4–5 is regular.