ECG theory

Question 1

What is the size of a ‘big’ square on an ECG?

Answer 1

5mm by 5mm

Question 2

What is the size of a ‘small’ square on an ECG?

Answer 2

1mm by 1mm

Question 3

Time is shown by what axis of the ECG graph?

Answer 3

X -axis

Question 4

What is the normal paper speed recording set at?

Answer 4

25mm/s

Question 5

If the paper speed is set at 25mm/s then what is the duration of one small square?

Answer 5

0.04s

Question 6

How many milliseconds are in one second?

Answer 6

1000

Question 7

If one second = 1000ms each small square is? in ms

Answer 7

40ms

Question 8

When would you want to change the paper speed of 25mm/s?

Answer 8

Tachycardia - Speed up paper speed - to see the complexes clear/ spread them out - cuts tracing to 5 seconds of information

Bradycardia- Speed up paper speed to see more complexes - Increases recording by 10 seconds

Question 9

What does the y-axis measure?

Answer 9

Amplitude in mV

Question 10

What is the standard wave forms for amplitude of the Y-axis measured at?

Answer 10

10mm/mv

Question 11

What is the amplitude of one small square is the amplitude is set at 10mm/mV?

Answer 11

0.1mV

Question 12

When would you want to change the standard setting of amplitude from 10mm/mV?

Answer 12

If complexes overlap