Tutorial 1: Rate

EKG machines generally calculate a rate by an automated algorithm. So the easiest way to get the rate is to read off the number the machine printed out. Sometimes this will give you the wrong answer: If for example the T-waves are huge as in hyperkalemia, the machine may confuse T-waves for QRS complexes and print out double the true rate. So it's worth practising getting the rate yourself - it'll come in handy.

There are 2 ways to read the rate on a standard EKG (standard means 5 big boxes = 1s):

1. Count big boxes with this sequence: 300,150,100,75,60,50 (this is Dubin's method)

So the rate in the above tracing is around 75 bpm. The trick here is to memorize the sequence 300,150,100,75,60,50 and then count the boxes with those labels as shown above.

2. The other method is 300/(number of big boxes between two QRS's)

Use whichever method you find easier ... they're really both the same. To be even more accurate, you can divide 1500 by the number of small squares. Now try it - what is the rate in the following tracing?

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If the rate is irregular, as in atrial fibrillation, there is a 3rd way to get the rate:

3. Count the number of QRS's across 1 page and multiply by 6 to get the rate.

Calculate the rate in the following EKG

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