15-Second EKG Interpretation: Atrial Fibrillation Pt 1 of 2

We will be talking about atrial rhythms and how to appropriately interpret them. We will determine if what you see on your monitor is atrial fibrillation or something entirely different.

Atrial Fibrillation

What happens when your client’s atrium runs wild or isn’t acting the way it’s supposed to be? Well, the most common rhythm that you’ll see in a clinical setting is something that’s called A-Fib or atrial fibrillation. Atrial fibrillation is the rapid firing of impulses in the right atrium with about 350 to 650 beats or impulses per minute.

Impulses are regulated by the atrioventricular (AV) node which mainly controls the number of impulses that passes along the ventricles. Without the presence of the AV node, and if the ventricles are beating at 650 a minute, there’s not enough amount of time to repolarize and get blood inside the ventricles, resulting to almost a full contraction.

This scenario is similar to the administration of potassium directly to your heart which would cause full contraction; meaning, the heart will contract and no longer open. If that happens, the heart will no longer receive and circulate blood with oxygen.

So, the main thing that you have to remember is that your heart’s primary function is to distribute oxygenated blood throughout the body and the AV node is there to regulate the number of impulses that are coming through inside the heart.  

Five Steps of Rhythm Interpretation

Step 1: Look for a P-wave

With your atrial fibrillation, the first sign to look for when interpreting heart rhythms is if there is the presence of a P-wave. If there’s NO P-wave in a rhythm, that’s a possibility for atrial fibrillation. The P-wave will not be present during atrial fibrillation because there is increased action or fibrillation happening around the node.

Step 2: Look for a PR wave

Since there is NO P-wave in your A-fib, a PR wave will also be absent. So you can easily count that out and move on to the next step.

Step 3: Look for a QRS wave

Typically, a QRS complex wave is between one to three boxes and is around 0.12 seconds. If this is a bit confusing for you, all you need to remember is that the QRS wave must be less than three boxes on your ECG or EKG paper and should be less than 0.12 seconds for an interpretation of atrial fibrillation.

Step 4 – Know the Rate

If the SA node inside the atriums is shooting out 350 to 650 beats per minute and the AV node will not allow that many to go through, the result is tachycardia. Your client will become tachycardic most of the time with atrial fibrillation. The rate will definitely increase, usually more than 100 beats per minute.

Step 5:  Know the Regularity

With atrial fibrillation, you will not have a regular rhythm – the EKG strip will show atypical rhythms popping all over the place; like a DJ throwing beats at parties. The rhythms will be irregular, sporadic, and will not be perfused, unlike the normal ones. This is due to the increased contractions happening within a minute and the AV node not allowing them to go through.

A Summary

As a quick review, the five criteria to take note of when identifying atrial fibrillation rhythms on your EKG strip are the following:

1. No P-wave
2. No PR wave
3. QRS wave is less than three boxes and is below 0.12
4. Tachycardia – more than 100 beats per minute
5. Regularity – all over the place or sporadic

If all of these are present on your EKG strip, you can be 99% sure that it’s atrial fibrillation.  

On our next discussion, we will focus on the therapeutic modalities that nurses should do with their clients that have atrial fibrillation. For more useful nursing information, visit us at SimpleNursing.com.