Cardiac channelopathies

Question 1

Occurrence of sudden cardiac death

Answer 1

70000UK, 60% ischaemic heart disease, 40% no detectable cause

Question 2

Speed of normal, long and short ventricular action potentials?

Answer 2

Normal-0.36s, long-0.45s, short-0.34s

Question 3

What is ventricular fibrillation?

Answer 3

Lack of coordination of cells in ventricles

Question 4

Cause of death for Long QT

Answer 4

Torsades de pointes and ventricular fibrillation

Question 5

Occurence of long QT

Answer 5

1:10000 to 1:15000

Question 6

LQT4 cause.

Answer 6

Ankyrin B protein for the sodium and potassium currents (loss of function)

Question 7

LQT5 cause.

Answer 7

Loss of function in Mink (B subunit protein which regulation Kv7.1a)

Question 8

What is the gene for Mink?

Answer 8

E1 gene

Question 9

How does a gain in function of calcium channels result in LQT?

Answer 9

Increase plateau

Question 10

Treatment for Long QT?

Answer 10

B blockers- class 2 antidysrhythmic e.g. atenolol a B1 (cAMP linked) selective receptor antagonist which slows down heart rate and has negative inotropic effects

Question 11

Who does short QT effect?

Answer 11

75% men- are adolescence

Question 12

What channels cause SQT,2,3,4,5?

Answer 12

Kv11.1a, Kv7.1a, Kir2.1a, Cav1.2a, Cav12B2

Question 13

Treatment for short QT.

Answer 13

Implant defibrillation, research suggests quinidine (K channel blocker)