EKG Rhythms: Accurate Interpretation in 3 Easy Steps Pt 2

Female doctor standing with arms crossed with heart rate background

Whether you’ve been out of school for 30 years or more, or finishing your nursing school but still have no idea how to do proper EKG interpretation and how the concepts work, this is for you.

For anyone of you who has trouble understanding the basics, Mike has made it uncomplicated to comprehend and remember the fundamentals of EKG rhythms. Guaranteed, you’ll be able to interpret EKG rhythms in three minutes or less!

Before getting into the core of this topic, let’s focus first on what an EKG is.

EKG is short for electrocardiogram; which simply means a picture of your heart or basically the activities of your heart.

The four-bedroom suite

In SimpleNursing.com, we make sure that you are able to relate every concept to what you are already familiar with. With EKG, it’s the heart. Consider your heart as a four-bedroom suite because it has four chambers and every chamber is divided by valves. These valves are like the French doors to your heart. 

The atriums

So, in the heart, there are upper rooms called atriums. The atriums are small upper chambers of the heart. These chambers, you can call refer to them as the attic or the guest rooms, they are the first ones to squeeze blood to the other chambers because the atriums are the rooms that first takes in the blood from the veins.

Remember: In all the chambers of the heart, the atriums are responsible for receiving unoxygenated blood which is blood that already circulated the body and have depleted oxygen supply.

The ventricles

Now, from the atriums, blood gets pushed down to the other chambers like the master’s bedroom or the living room. These chambers that are located below the atriums are referred to as the ventricles. 

EKG application

By keeping in mind the concept above, you can easily determine how the heart works in an EKG strip. What does each wave represent?

  • P wave – appears first, signifies your atriums pumping blood
  • QRS wave – next to appear, signifies your ventricles squeezing blood
  • T wave – relaxation or repolarization of the ventricles

So this set-up is like the principle in physics: what goes up must come down. That’s basically what you’ll see on your EKG paper.

Zooming in 

Medically speaking, the “atrial squeeze” seen on your P wave is called atrial depolarization. Depolarization is simply sending a charge away by pushing the blood out of the heart. Once the blood goes into ventricles, it takes all the blood in, making those chambers swell. The ventricles need to squeeze the blood out of their chambers which is basically your ventricle depolarization. 

After the ventricles have depolarized blood out of it chambers, it needs to re-polarize or relax. So basically your T wave is medically referred to as ventricular repolarization. 

Oxygen distribution

Here’s a quick question. Before the left ventricle has squeezes blood out of its chamber and into the aorta, where should blood go first to be oxygenated before it gets distributed to the different parts of the body?

So, here’s how the blood flows in the heart:

The right atrium receives unoxygenated blood then in pumps the blood to the right ventricle. The right ventricle is expected to be big enough to get the necessary pressure to pump the blood into the lungs. From the lungs, as we inhale oxygen and exhale carbon dioxide, blood becomes oxygenated. Oxygenated blood from the lungs goes into the left atrium and finally, it gets pumped into the left ventricle. The left ventricle, being a big chamber, is basically responsible for squeezing oxygenated blood from its area into the aorta to the different parts of the body.


Quick recap

P wave – atrial depolarization

QRS wave – ventricular depolarization

T wave – ventricular repolarization

To apply what you now know, here’s a critical thinking question:

Why isn’t there a P wave repolarization on your EKG strip (“earthquake paper” as Mike likes to call it)?

There is actually P wave relaxation; however, it doesn’t appear on your EKG strip because the QRS wave is covering it.

That’s a little trivia for you.

So this is how the heart normally works. In the next segment, you will be able to learn what goes amiss in your heart conduction. There is still tons of nursing information in our SimpleNursing.com database. Aside from more EKG content, you can also drop by to check out on our wide variety of topics on anatomy and physiology, nursing fundamentals, and more.