The electrical conduction system of the heart is responsible for the EKG tracing you see on a patient. In order to be able to analyze a rhythm strip, you must first learn how the electrical system of the heart works. As I’ve said many times before, this was my least favorite thing learning in nursing school. I found the heart to be too complicated, but I finally found out that I was the one being complicated and the heart is actually easy to learn.
In this article, I want to share with you my knowledge on how the electrical system of the heart works and give you some study tips to help guide you for when you are preparing for your lecture exams or NCLEX. The electrical system of the heart is just as easy to learn as the blood flow of the heart, once you know the important areas to study.
First, I think to learn the electrical system of the heart, you have to be able to visualize it. Here is a drawing on how to the electrical system is set-up in the heart.
Let’s go through the order of how the electric impulses flow through the heart muscle to make the PQRST wave you see on the EKG tracing.
1.) Impulse starts in the SA NODE (Sinoatrial node)
Study Tip: On exams, you will most likely be asked what is the “pacemaker” of the electrical system and the answer is the SA node. The SA node beats at 60-100 bpm. Furthermore, the SA node represents the P-wave (atrial contraction) on the EKG tracing.
2.) Travels down through the internodal pathways to the AV NODE (Atrioventricular node)
Study Tip: For exams, know that the AV node is known as the “gatekeeper“. The AV node is known for causing a delay so the atrium can fully empty into the ventricles. If there wasn’t a delay the atriums would not fully empty into the ventricles which would cause problems. The AV node beats at 40-60 bpm.
3.) Then the impulse travels through the BUNDLES OF HIS which branches out into the RIGHT & LEFT BRANCH BUNDLES
4.) Lastly, the impulse travels to the PURKINJE FIBERS and then starts all over.
Study Tip: The purkinje fibers beat at 20-40 bpm.
Video Explanation on the Electrical System of the Heart
Now test your knowledge on how well you grasp the material. The quiz will assess if you know the electrical system and how it works. Here is the quiz.