Anti-Arrhythmic Drugs

Question 1

Class 1
Quinidine
Procainamide
Lidocaine

Answer 1

MOA: Na channel inhbitor
Effect: decrease Na current, thereby prolonging QRS phase, reducing HR and cardiomyocyte excitability
Use: mostly for ventricular arrhythmias, particularly tachycardias - some use in supraventricular arrhythmias too

Question 2

Class 2
Metoprolol
Atenolol

Answer 2

MOA: B1 adrenergic antagonist, few side effects
Effect: negative chronotropic, dromotropic, inotropic
Use: supraventricular tachycardias, particularly where excessive sympathetic stimulation is the cause

Question 3

Class 3
Amiodarone
Bretylium
Sotalol

Answer 3

MOA: K channel inhibitor
Effect: decrease K current, thereby prolonging repolarization phase and reducing HR
Use: refractory ventricular tachycardias, especially those arising from reentry

Question 4

Class 4
Verapamil
Diltiazem

Answer 4

MOA: Ca channel inhibitor
Effect: decrease Ca current; main effect as a negative chronotropic is its effect to slow spontaneous depolarization in pacemaker cells
Use: supraventricular tachycardias; good choice in HCM