Understanding rhythm strips. EKG or ECG
both stand for Electrical Cardio Graph. Let’s break this word down. Electrical current moving from one area to another. Cardio referring to the heart. Graphic displays electricity moving through the heart. This video will focus on a graph part and future videos will build on top of this foundation. The graph shows time horizontally and amplitude vertically. The graph has smaller boxes inside larger boxes. Twenty-five small boxes (five columns in five rows.) are in one large box. The reason for these boxes is to make it easy to count the time between electrical events. When we get into measuring the ECG waves, knowing how to measure the time interval between electrical events will help in diagnosing heart abnormalities. Let me say this another way. A metronome keeps consistent rhythm. If we graph a rhythm from a metronome it’ll be easy to see and hear when the metronome malfunctioned. A normal ECG recording should keep a consistent rhythm, very much like the metronome. An abnormal ECG shows where the rhythm is off. And is used to diagnose where the abnormality in electrical current has occurred. So first let’s focus on how to use the graph to measure electrical impulses. The rhythm strip has smaller boxes within a larger box. Each small box represents 0.04 of a second. Five small boxes are one large box, so 0.04 times five small boxes equals 0.20 seconds in one large box. And just like five twenty-dollar bills equals one hundred dollars. Five large boxes equals one second. Now let’s discuss the six second method of calculating heart rate. Which is preferred by many medical professionals. The reason this method is preferred is because counting one minute would be a very long strip and would get confusing. But six seconds is a manageable length of time. After counting the number of beats in six seconds and multiply that by ten, that number is your heart rate. Let’s do one. Here is a six second strip. How many beats are in this strip? … Five times ten equals fifty beats per minute. Let’s do another one just because this is so much fun. How many beats in this six second strip? … Eight beats times ten the heart rate is eighty. There’s another method commonly used but this one you just have to memorize. And you should skip this part if you’re still working on what we’ve just talked about. You could always come back later if you want. But learning what we’ve already talked about will get you going. The square counting method is used to get a quick estimate and all that is needed is two beats. However, I will not go into great detail on why this method works, There are many explanations online if you want
that much detail. Later videos I will bring up the square counting method again where it is more relevant. To use this method locate the tall waveform and find the one that lines up on the edge of a large box. The first large box after the one that you’ve lined up is considered to be 300 beats per minute. The second
large box represents 150 beats per minute. And the third large box equals 100, the fourth box equals 75, and the fifth large box is 60 beats per minute. This is just straight memorization of the value for each box and it can get more complex if you like doing math. but if you have two beats you can get an
estimate of the heart rate. Let’s do two examples. First locate the tall waveform and find the one that lines up on the edge of a large box. Add the values of each box between the tall wave forms. And you’ll have a rate of 150. Let’s do one more. Locate the tall waveform and find the one that lines up on the edge of the large box. Now add the values of each box. Then where the second tall wave lands give it an estimate about 75 beats per minute. So this is a foundation that we will build on. The next video will start explaining the record pattern produced by the ECG machine. Understanding the concepts in this video be key to continuing your ECG education.