Electrocardiograms (ECG)

Question 1

What are ECGs used to record?

Answer 1

The electrical activity of the heart as it contracts

Question 2

How do ECGs measure the heart contractions?

Answer 2

Measure tiny little electrical differences in your skin measured by sticking electrodes to skin

Signals picked up + fed into machine + an ECG trace is produced

Question 3

What does the P wave represent?

Answer 3

Atrial depolarisation

Question 4

What does the QRS complex represent?

Answer 4

Ventricular depolarisation

Question 5

What is the R wave?

Answer 5

The initial positive deflection

Question 6

What is the S wave?

Answer 6

The negative deflection following the R wave

Question 7

What is the Q wave?

Answer 7

The first downward wave of the QRS complex (often absent)

Question 8

What does the T wave represent?

Answer 8

Ventricular repolarisation

Question 9

What is bradycardia?

Answer 9

When heart rate slows down to below t0bpm

• People has]ve this bc theyre fit, training makes body beat slower + efficiently
• Severe bradycardia may need pacemaker to keep heart beating steadily

Question 10

What is an ectopic heartbeat?

Answer 10

Extra heartbeats that are out of normal rhythm

• Most ppl have at least 1 a day
• Usually normal but can be linked to serious conditions when frequent

Question 11

What is tachycardia?

Answer 11

When. heartbeat is very rapid, over 100bpm

• Often normal, e.g. when u exercise, have a fever, angry, etc
• If abnormal, may be caused by problems in electrical control of heart + may need to be treated by medication or surgery

Question 12

What is atrial fibrillation?

Answer 12

Example of an arrhythmia = abnormal rhythm in heart

Question 13

What happens during atrial fibrillation?

Answer 13

Rapid electrical impulses generated in atria + contract fast (fibrillate) upto 400 times a minute

However, they dont contract properly + only some impulses passed onto ventricles, which contract less often

As result, heart doesnt pump blood efficiently