EP

Question 1

Normal H-V interval

Answer 1

35-55 seconds
(class 1 indication for PPM if prolonged on EPS)

Question 2

Class Ia AADs & mechanism

Answer 2

Disopyramide, quinidine, procainamide
(Double Quarter Pounder)

Fast sodium channel blockade –> depresses phase 0 –> prolonged repolarization

Question 3

Class Ib AADs & mechanism

Answer 3

Lidocaine, mexelitine
(Lettuce & Mayo)

Fast sodium channel blockade –> selective depression of phase 0 in abnormal tissue –> decreases repolarization time

Question 4

Class Ic AADs & mechanism

Answer 4

Flecainide, propefanone
(Fries Please)

Fast sodium channel blockade –> Depresses phase 0 markedly, minimal effect on repolarization

(show use dependence)

Question 5

Class II AADs & mechanism

Answer 5

Beta blockers
Decrease slope of phase 4

Question 6

Class III AADs & mechanism

Answer 6

Sotoalol
Amiodarone
Dofetilide
Ibutilide

K+ channel blockade –> prolong phase 3
(show reverse use dependence)

Question 7

Class IV AADs & mechanism

Answer 7

CCBs
Prolongs phase 2

Question 8

Drugs for pre-excited AF

Answer 8

Procainamide
Ibutilide

Question 9

TdP invariably has a coupling interval of:

Answer 9

> 400 ms

Question 10

T wave alternans is associated with:

Answer 10

Long QT (congenital or acquired) with high risk of TdP