Normal ECG

Question 1

Smallest square =

Answer 1

0.04 s, 1 mm

Question 2

Large square=

Answer 2

0.2s, 5mm

Question 3

Normal P wave

Answer 3

Negative in AVR

Positive in II

Question 4

Normal variations of P wave

Answer 4

Biphasic in V1 but more + than -

Question 5

P wave duration and amplitude

Answer 5

120 ms (3 small squares)
0.25 mV (2.5 small squares)

Question 6

PR interval definition

Answer 6

Beginning of P to beginning of Q

Question 7

Normal PR interval duration

Answer 7

110-200 ms

2.5 to 5 small squares

Question 8

Normal Axis

Answer 8

-30 to +90 degrees

Question 9

Axis:

I + and II +

Answer 9

Normal

Question 10

Axis:

I + and II -

Answer 10

LAD

Question 11

Axis:

I - and II +

Answer 11

RAD

Question 12

Axis:

I - and II -

Answer 12

Extreme RAD

Question 13

Normal QRS duration

Answer 13

<120 ms (3 small squares)

Question 14

Normal R or S amplitude

Answer 14

25 mm

Question 15

Normal point of polarity change for precordial leads

Answer 15

V3, V4

Question 16

Normal QT

Answer 16

F Less than 460 ms
M Less than 450 ms

More than 500 ms- risk of VT

Question 17

Variation of QT between leads

Answer 17

QT dispersion- evidence of myocardial disease

Question 18

Normal T wave

Answer 18

negative in aVR and V1 (if in V1, may also be in V2)