Exam 6 - Antiarrhythmic Drugs Flashcards
Causes of arrhythmias: abnormal automaticity
- enhanced automaticity of SA node
- damaged myocardial cells
- after-depolarization (abnormal impulses) triggered by abnormal calcium influx provoked by digoxin toxictiy
Causes of arrhythmias: abnormalities in impulse conduction
- reentry (most common cause of arrhythmias)
- unidirecitonal
Drug induced arrhythmias
- Sympathetic drugs
- Hypokalemia increase automaticity
- Digoxin
- Antiarrhythmic, antipsychotic drugs (ziprasadone)
- DO NOT USE ANTIARRHYTHMICS IN HF
Drug induced arrhythmias: Sympathetic drugs
- increase automaticity of SA and AV
- produces tachyarrhythmia
Drug induced arrhythmias: Digoxin
- evokes after-depolarization (abnormal impulses) by increasing calcium influx into cardiac cells - can lead to extrasystole and tachycardia (toxic concentration)
- impair AV node conduction
Drug induced arrhythmias: antiarrythmias, antipsychotic drugs
slow ventricular repolarization and cause QT prolongation evokes torsade de pointes
When should you not use antiarrhythmic?
Do not use antiarrhythmic in HF (except Amiodarone and Dofetilide)
Class IA
Na+ channel blocker
K+ channel blocker
Class IB
Na+ channel blocker
Class IC
Na+ channel blocker
Class II
B-adrenergic blocker
Class III
K+ channel blocker
Class IV
Ca2+ channel blocker
Procainamide
Class I Na+ channel blocker
Procainamide MOA
binds to sodium and potassium channels
Procainamide indiations
ACLS guidelines
- stable Wide-QRS tachycardia (ventricular arrhythmia
Procainamide adverse effects
- systemic lupus erythematosus
- Torsade de pointes
Lidocaine
Class IB
What is Lidocaine?
Local anesthetic and has antiarrhythmic activity (more pronounced effect on ischemic tissue)
Lidocaine indications
- ACLS guidelines
- ALTERNATIVE TO AMIODARONE IN VENTRICULAR FIBRILLATION (VF)
- pulseless ventricular tachycardia (PVT)
Propafenone
Class IC
Propafenone pharmacokinetics
Beta-blocker properties
Propafenone indications
Atrial fibrillation (AF)
Propafenone adverse effects
Bronchospasms