02.03 Calculating Heart Rate

Hey guys, in this lesson we are going to talk about how to calculate a heart rate on an EKG strip
So I am going to show you guys how to calculate a heart rate on an EKG strip with 3 different methods. Counting the QRS, 300 method and 1500 method. It sounds a lot worse than what it really is I promise. You will all be pros’ by the time we are done!

The first method I am going to show you is counting the QRS, you need to identify the marks above the strip, mainly you are looking for the 3 second marks, which are every 15 big boxes. So they would be here and here. So this is a 6 second strip- you need to always try to identify 6 second strips. Here you will count the QRS complex, so we have 7. You would multiply 7 x 10 = 70, your heart rate is 70 beats per minute. Why 10 you ask? Well that is because it is a 6 second strip, so 6x10 is 60 seconds or a full minute. That is why you have to have a 6 second strip in order to count a heart rate using this method. If the patient is having an irregular heart rhythm, this method is a little harder to do.

The second method I am going to show you is called the 300 method or rule of 300. Let’s make life simple and simplify this! FIrst thing you do is pick 2 QRS complex, so we would pick from here to here. Then you count the number of large boxes in between the QRS complex, so here we have 4 large boxes. So we would divide 300/4 and get 75 beats per minute. Why 300 you ask? That is because there are 300 large boxes in 60 seconds. Remember that each large box is 0.20 seconds so 300 x 0.20 is 60 seconds. This method is more accurate, however, if the rhythm is not regular, it is a little harder to count only 2 QRS complex and get the number of boxes when the QRS is not regular with each beat. If you remember on the previous slide when we counted the QRS and multiplied by 10, we got 70, here we are getting 75 so it shows to be more accurate.

The third method I am going to show you is the 1500 method. Like the last one you pick 2 QRS complex, so we would pick these 2. Now you count the number of small boxes in between the 2 QRS complex. So here we have 20 small boxes. So then we divide 1500 by 20 and get 75 beats a minute. And like before, why 1500 you ask. Well let me tell you! Keep this simple guys, there are 1500 small boxes in 60 seconds. Each small box is 0.04 seconds so 1500 x 0.04 is is 60 seconds. This method is a lot more accurate, but like the others if the rhythm is irregular, it is a little more difficult to count a heart rate. So what is the best thing to do if your patient has an irregular heart beat? Check the apical pulse and count for a full minute!



So to recap, these are the key points you need to remember to calculate a heart rate on an EKG. If you are counting the QRS make sure you have a 6 second strip and multiply by 10. If you are using the 300 method count the large boxes in between the QRS and divide 300 by that number. And the 1500 method you count the small boxes in between 2 QRS and divide 1500 by the number of small boxes. Honestly guys most nurses count the QRS and multiply by 10, however it is always best to check that apical pulse when in doubt or when the patient has an irregular heart rate!

I hope this has helped you guys and make sure you keep this simple, we have some sample strips on the cheat sheets, try to practice all 3 methods to get better at calculating the heart rates. Also make sure that you check out all of the resources attached to this lesson. Now, go out and be your best self today! And, as always, happy nursing!