1
00:00:04,620 --> 00:00:16,560
Determining Heart Rate on an ECG Strip, by
Dr. Douglas Mah.
2
00:00:16,560 --> 00:00:20,960
When looking at the rates, there are two different
ways of figuring out what a patient's heart
3
00:00:20,960 --> 00:00:23,439
rate is on an ECG tracing.
4
00:00:23,439 --> 00:00:28,529
The mathematical way is counting those number
of small squares between each QRS complex.
5
00:00:28,529 --> 00:00:31,260
Each small square is 40 milliseconds.
6
00:00:31,260 --> 00:00:36,160
Counting the number of squares between each
QRS complex and multiplying it by 40 milliseconds
7
00:00:36,170 --> 00:00:38,460
gives you the cycle length of a patient's
heart rate.
8
00:00:38,460 --> 00:00:43,300
You then divide 60,000 by the cycle length,
and this will give you the heart rate in
9
00:00:43,300 --> 00:00:45,320
beats per minute.
10
00:00:45,320 --> 00:00:47,460
Another way to do it is the estimation method.
11
00:00:47,469 --> 00:00:54,020
If you presume a QRS complex starts on a thick
line and then you count 300, 150, 100, 75,
12
00:00:54,020 --> 00:00:59,079
et cetera, you can then see where the next
QRS complex lands and get a rough estimation
13
00:00:59,079 --> 00:01:01,059
of what the patient's heart rate is.
14
00:01:01,059 --> 00:01:03,760
For example, what is this patient's heart
rate?
15
00:01:03,760 --> 00:01:09,160
If we do the mathematical method, we can count
21 small squares between each QRS complex.
16
00:01:09,160 --> 00:01:14,600
21 multiplied by 40 milliseconds gives you
840 milliseconds.
17
00:01:14,600 --> 00:01:19,340
If you divide 60,000 by 840, you get 71 beats
per minute.
18
00:01:19,340 --> 00:01:24,460
Now, if we do the estimation method, we then
find the QRS complex closest to a thick line
19
00:01:24,460 --> 00:01:26,250
on the EKG.
20
00:01:26,250 --> 00:01:32,890
You then count 300, 150, 100, 75, and you
can see the next QRS complex lands around
21
00:01:32,890 --> 00:01:34,930
this area.
22
00:01:34,930 --> 00:01:38,450
This gives an estimated heart rate of 75 beats
per minute, which is pretty similar to the
23
00:01:38,450 --> 00:01:41,430
71 beats per minute we calculated mathematically.
24
00:01:41,430 --> 00:01:46,390
Another way to do it is divide 300 by the
number of large squares between each QRS complex.
25
00:01:46,390 --> 00:01:49,060
For this example, divide 300 by 4.
26
00:01:49,060 --> 00:01:52,060
This gives an estimated heart rate of 75 beats
per minute.