EP

Question 1

Dofetilide

Answer 1

Class 3
Blocks k efflux, prolongs refractoriness
Reverse use dependence - increased effects at lower rate

Question 2

AV block

Answer 2

AV block may be due to failure of impulse propagation:

• in the AV nodal tissues (narrow QRS complex). Mobitz 2 type 1
• within the His-Purkinje system (intra- or infra-Hisian block). Mobitz 2 type 2 —>Associated with a wide QRS complex with right or left bundle branch or fascicular block.

Exercise (sympathetic) will improve AV nodal conduction and worsen His Purkinje conduction