Article 1

Question 1

What is brugada syndrome caused by?

Answer 1

Loss of function mutations in the cardiac sodium channel gene
South Asian populations

Question 2

Long QT syndrome

Answer 2

Distorted form of ECG
Rare mutation in HERG potassium channel 
The heart doesn’t pump blood as effectively 
Brain deprived of oxygen 
Abrupt loss of consciousness

Question 3

What is LQT precipitated by?

Answer 3

Stress
Fear
Excitement

Question 4

Drug: terfendine

Answer 4

Prolongation of QT interval
Sudden death
Blocks HERG potassium channels

Question 5

Nitroglycerin

Answer 5

Releases nitric oxide
Stimulate the production of cyclic GMP
Causes blood vessels to relax

Question 6

Beta blockers

Answer 6

Block the action of adrenaline
Prevent it binding to beta-adrenoceptor in the heart membrane
Speed up heart

Question 7

What is the maximum human heart rate

Answer 7

200 beats per minute

Question 8

Why does potassium chloride stop the heart?

Answer 8

At high concentration, it depolarises the heart cells so much that sodium and calcium channel are switched off
No action potentials are generated
Heart simply stops