Antiarrythmic Drugs Flashcards
Name the 5 phases of an action potential
Phase 0: Upstroke
Phase 1: Early-fast repolarisation
Phase 2: Plateau
Phase 3: Repolarisation
Phase 4: Diastole
Define excitability
Cell can change its internal electrical balance to reach threshold
Define automaticity
Cell can generate an electrical impulse without itself being stimulated
Define conductivity
Cell can transfer an electrical impulse to the next cell
Name the 6 classes of antiarrythmic drugs
Class 1A
Class 1B
Class 1C
Class II
Class III
Class IV
Class I antiarrythmics are ____ blockers
Sodium channel
Class II antiarrythmics are ____ blockers
Beta
Class III antiarrythmics are ____ blockers
Potassium channel
Class IV antiarrythmics are ____ blockers
Calcium channel (Non-DHP)
State the duration of actions of class 1A, 1B and 1C antiarrhythmics
1A: Intermediate acting
1B: Fast acting
1C: Slow acting
Name a class 1A antiarrhythmic
Procainamide
Effect of procainamide on phases
Reduces rate of phase 0 rise
Effect of procainamide on conductivity
Reduces
Effect of procainamide on automaticity
Reduces
Effect of procainamide on ERP
Increases
Effect of procainamide on APD
Increases
Name a class 1B antiarrhythmic
Lidocaine
Effect of lidocaine on phases
- Reduces rate of phase 0 rise
- Shortens phase 3 repolarisation
Effect of lidocaine on conductivity
Little effect
Effect of lidocaine on automaticity
Reduces
Effect of lidocaine on ERP
No change
Effect of lidocaine on APD
Reduces
Name a class 1C antiarrhythmic
Flecainide