The ECG

Question 1

What does a normal QRS complex look like?

Answer 1

Question 2

What is the P wave?

Answer 2

Atrial depolarisation

Question 3

What is the PR interval

Answer 3

The time from atrial depolarisation to ventricular depolarisation. It runs from P wave to the start of the QRS

Normal = 0.12 - 0.20s (3-5 little squares)

1 little square = 0.04ms

Question 4

What is the QRS complex?

Answer 4

Complete depolarisation of ventricle

Normal is <0.12s

Question 5

What is the T wave?

Answer 5

Ventricular repolarisation

Question 6

What is the QT interval?

Answer 6

Whole electrical activity of the ventricle

Question 7

How long does 1 large square represent?

Answer 7

0.2seconds

Question 8

How long does 5 large squares represent?

Answer 8

1s

Question 9

How do you calculate HR?

Answer 9

300/large squares R-R

Question 10

What is the cardiac axis?

Answer 10

The route of depolarisation

Question 11

How do you work out the cardiac axis?

Answer 11

Look at lead 1 and AVF R WAVE

Use 1 first, count up or down for left and right

Use avf, use up to go toward it and down to go away

http://en.ecgpedia.org/wiki/QRS_axis

Question 12

What is a cause of LAD?

Answer 12

Left ventricular hypertrophy due to aortic stenosis

Question 13

What is a cause of RAD

Answer 13

Right ventricular hypertrophy due to lung disease

Question 14

What causes U waves?

Answer 14

Hypokalaemia