3.2.10- Electrocardiograms

Question 1

What is electrocardiography used for?

Answer 1

Electrocardiography can be used to monitor and investigate the electrical activity of the heart
Electrodes that are capable of detecting electric signals are placed on the skin
These electrodes produce an electrocardiogram (ECG)
An ECG shows a number of distinctive electrical waves produced by the activity of the heart
A healthy heart produces a distinctive shape in an ECG

Question 2

What is the P wave?

Answer 2

Caused by the depolarisation of the atria, which results in atrial contraction (systole)

Question 3

What is the QRS complex?

Answer 3

Caused by the depolarisation of the ventricles, which results in ventricular contraction (systole)
This is the largest wave because the ventricles have the largest muscle mass

Question 4

What is the T wave?

Answer 4

Caused by the repolarisation of the ventricles, which results in ventricular relaxation (diastole)

Question 5

What is the U wave?

Answer 5

The U wave
Scientists are still uncertain of the cause of the U wave, some think it is caused by the repolarisation of the Purkyne fibres

Question 6

What is Tachycardia?

Answer 6

When the heart beats too fast it is tachycardic
An individual with a resting heart rate of over 100 bpm is said to have tachycardia

Question 7

What is Bradycardia?

Answer 7

When the heart beats too slow it is bradycardic
An individual with a resting heart rate below 60 bpm is said to have bradycardia
A lot of fit individuals or athletes tend to have lower heart rates and it is usually not dangerous

Question 8

What is an ectopic heartbeat?

Answer 8

This condition is caused by an early heartbeat followed by a pause
It is common in the population and usually requires no treatment unless very severe

Question 9

What is fibrillation?

Answer 9

An irregular heartbeat will disrupt the rhythm of the heart
Severe cases of fibrillation can be very dangerous, even fatal