# Work out cardiac cycle and heart rate

1. Nov 11, 2015

I would just like to know if i have worked out one cardiac cycle and heart rate correctly.
I have attached the image of the ecg called 'after exercise'

here are my workings out:

1. CARDIAC CYCLE:

there are 4 cycles so:
9 (grids) x 0.05 = 0.45
9x 0.05 = 0.45
9x 0.05 = 0.45
9x 0.05 = 0.45

average = 0.45 x 4/4 = 0.45

so cardiac cycle = 0.45 seconds

2. HEART RATE:
60/0.45 =133 bpm

are these worked out correctly?

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Last edited: Nov 11, 2015
2. Nov 11, 2015

### Staff: Mentor

I'm seeing one heartbeat every 10 grid lines. Are you sure about your 9 grid lines number?

3. Nov 11, 2015

Oh, dammit i was counting the spaces between the lines.
So you have to count the lines? then yeah it should be 10.

so its:
1. CARDIAC CYCLE:
there are 4 cycles so:
10 (grids) x 0.05= 0.5
10x 0.05 = 0.5
10x 0.05 = 0.5
10x 0.05 = 0.5

average = 0.5 x 4/4 =0.5

so cardiac cycle = 0.5 seconds

2. HEART RATE:
60/0.5 = 120 bpm

is this right??

4. Nov 11, 2015

### Staff: Mentor

That's what I got as well.

5. Nov 11, 2015

i just uploaded another ECG called 'resting' as i cant tell how many grids there are. I counted 15 ? for each cycle, what about you?

6. Nov 11, 2015

### Staff: Mentor

Yep, I get 15 as well.