Heart & Diabetes Pharmacology III: Drugs and the Heart II Flashcards
1
Q
What are the FOUR classes of Vaughan Williams drugs?
A
- Class I - Na+ channel blockers
- Class II - β-blockers (target SA node)
- Class III - K+ channel blockers
- Class IV - Ca2+ channel blockers
2
Q
What are the effects of Class I drugs on action potentials?
A
Non-nodal
* slows Phase 0 depolarisation
* some alter APD & ERP
* slow conduction velocity
3
Q
What are the effects of Class II drugs on action potentials?
A
Decrease sinus rate (SA) and conduction through the AV node
4
Q
What are the effects of Class III drugs on action potentials?
A
Prolong Phase 3 dépolarisation (ERP & APD)
* slow conduction velocity
5
Q
What are the effects of Class IV drugs on action potentials?
A
- Main effects on SA & AV nodes
- Slow Phase 0 depolarisation
- Decrease sinus rate (SA) and conduction velocity