Antiarrhythmics Flashcards
What are the class Ia antiarrhythmics?
Quinidine, Procainamide, Disopyramide
What is the MOA of Quinidine?
Blocks cardiac Na channels to increase excitation threshold
What are the EKG manifestations of Quinidine?
Increase in QRS and QT; PR changes can be variable
When would you use Quinidine?
Supraventricular (AV node and above) and Ventricular Arrhythmias; PO, can block alpha receptors, decreases digoxin clearance and increases Digoxin toxicity;
What are the side effects of Quinidine?
NVD, Cinchonism, Torsade de Pointes, Prolongs RP; hyperkalemia may increase toxicity
What is the MOA of Procainamide?
Blocks cardiac Na channels to increase excitation threshold
What are the EKG manifestations of Procainamide?
Increase in QRS and QT, PR changes can be variable
When would you use Procainamide?
Ventricular Arrhythmias; Good PO and available IV; No alpha receptor interference; Half excreted, half converted to class 3 arrhythmic metabolite (NAPA); short (3-4hr) half life; sustained release preparations
What are the side effects of Procainamide?
Formation of ANA, Lupus-like syndrome; Prolongs RP; hyperkalemia may increase toxicity
What is the MOA of Disopyramide?
Blocks cardiac Na channels to increase excitation threshold
What are the EKG manifestations of Disopyramide?
Increase in QRS and QT; PR changes can be variable
When would you use Disopyramide?
Ventricular arrhythmias when other drugs dont work; use cautiously
What are the side effects of Disopyramide?
High anticholinergic effects; Prolongs RP; hyperkalemia may increase toxicity
What are the class Ib antiarrhythmics?
Lidocaine, Mexiletine, Tocainide
What is the MOA of Lidocaine?
Acts on inactivated Na Channels, esp those that are ischemic or rapidly-driven; minimal K channel blockade; phase 4 automaticity and afterpotentials decreased
What are the EKG manifestations of Lidocaine?
Decrease in QT; Decreased APD; ERP/ADP increased
When would you use Lidocaine?
Ventricular arrhythmias; IM via LidoPen
What are the side effects of Lidocaine?
Lidocaine toxicity (cardiac depression, bradycardia, asystole)
What is the MOA of Mexiletine?
Acts on inactivated Na channels, esp those that are ischemic or rapidly-driven; minimal K channel blockade; phase 4 automaticity and afterpotentials decreased
What are the EKG manifestations of Mexiletine?
Decrease in QT; Decreased APD; ERP/ADP increased
When would you use Mexiletine?
Ventricular arrhythmias
What are the side effects of Mexiletine?
GI/CNS disturbances
What is the MOA of Tocainide?
Acts on inactivated Na channels, esp those that are ischemic or rapidly-driven; minimal K channel blockade; phase 4 automaticity and afterpotentials decreased
What are the EKG manifestations of Tocainide?
Decrease in QT; Decreased APD; ERP/ADP increased
When would you use Tocainide?
Ventricular Arrhythmias; need periodic blood cell counts
What are the side effects of Tocainide?
GI/CNS disturbances, agranulocytosis and blood dyscrasias
What are the class Ic antiarrhythmics?
Flecainide, Propafenone, Moricizine
What is the MOA of Flecainide?
Decreases depolarization/conduction, especially in BoH-PF system
What are the EGK manifestations of Flecainide?
Increase PR and QRS; unchanged QT
When would you use Flecainide?
Serious supraventricular arrhythmias
What are the side effects of Flecainide?
Potential for lethal arrhythmias; > increased morbidity post-MI
What is the MOA of Propafenone?
Decreases depolarization/conduction esp in BoH-PF system; weak beta-blocking activity
What are the EKG manifestations of Propafenone?
Increase in PR and QRS; QT unchanged