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
When would you use Propafenone?
Serious supraventricular arrhythmias
What are the side effects of Propafenone?
Potential lethal arrhythmias
What is the MOA of Moricizine?
Decreases depolarization/conduction, esp in BoH-PF system
What are the EKG manifestations of Moricizine?
Increase in PR and QRS; QT unchanged
When would you use Moricizine?
Serious ventricular arrhythmias
What are the side effects of Moricizine?
Potential lethal arrhythmias; increased morbidity post-MI
What are the class II antiarrhythmics?
Propranolol, Metoprolol, Atenolol, Esmolol
What is the MOA of Propranolol?
Decrease SNS stimulation of SA node, AV node, PFs, and ventricles; beta blocker
What are the EKG manifestations of Propranolol?
Increased PR; QRS and QT unchanged
When would you use propranolol?
Supraventricular and ventricular tachyarrhythmias, PVCs
What is the MOA of Metoprolol?
Decrease SNS stimulation of SA node, PFs, and ventricles; Beta blocker
What are the EKG effects of Metoprolol?
Increased PR; QRS and QT unchanged
When would you use Metoprolol?
Supraventricular and ventricular tachyarrhythmias PVCs
What is the MOA of Atenolol?
Decrease SNS stimulation of SA node, AV node, PFs and ventricles; beta blocker
What are the EKG manifestations of Atenolol?
Increased PR; QRS and QT unchanged
When would you use Atenolol?
Supraventricular and ventricular tachyarrhythmias, PVCs
What is the MOA of Esmolol?
Decrease SNS stimulation of SA node, AV node, PFs and ventricles; beta blocker; metabolized by RBC esterases
What are the EKG manifestations of Esmolol?
Increased PR; QRS and QT unchanged
When would you use Esmolol?
Supraventricular and ventricular tachyarrhythmias; PVCs; emergency IV treatment for A Flutter/AFib and sinus tachycardia; 9min half life
What are the class III antiarrhythmics?
Sotalol, Bretylium, Ibutilide, Dofetilide, Amiodarone
What is the MOA of Sotalol?
Non-selective beta-blocker that also has class III action; K channel blocker
When would you use Sotalol?
Ventricular arrhythmias
What are the side effects of Sotalol?
Proarrhythmias possible
What is the MOA of Bretylium?
Blocks K channels and depletes neuronal release of catecholamines
When would you use Bretylium?
Serious ventricular fibrillation; as emergency IV
What is the MOA of Ibutilide?
Blocks K channels
When would you use Ibutilide?
Rapid conversion of AFib/AFlutter to NSR; IV
What is the MOA of Dofetilide?
Blocks K Channels
When would you use Dofetilide?
Maintains NSR in AFib patients; inpatient due to ADR potential
What are the side effects of Dofetilide?
Proarrhythmias possible
What is the MOA of Amiodarone?
Has Class 1-4 effects; structural analog of thyroxine; K channel blocker
What are the EKG manifestations of Amiodarone?
Increased PR, QRS, and QT; increased RP, ERP, APD
When would you use Amiodarone?
Supraventricular and ventricular arrhythmias; >50day half life
What are the side effects of Amiodarone?
Blue deposits in eyes/skin; pulmonary fibrosis, GI disturbances, thyroid issues, cardiac issues; increases toxicity of digoxin and warfarin
What are the class IV antiarrhythmics?
Verapamil, Diltiazem
What is the MOA of Verapamil?
Blocks Ca channels to slow SA rate and AV conduction
What are the EKG manifestations of Verapamil?
Increased PR
When would you use Verapamil?
Suppress ventricular rate in AFlutter/AFib
What are the side effects of Verapamil?
Constipation, hypotension, bradycardia, AV block; Increased dose decrease myocardial contractility
What is the MOA of Diltiazem?
Blocks Ca channels to slow SA rate and AV conduction
What are the EKG manifestations of Diltiazem?
Increased PR
When would you use Diltiazem?
Suppress Ventricular rate in AFlutter/AFib
What are the side effects of Diltiazem?
Hypotension, bradycardia, AV block; increased doses decrease myocardial contractility
What is the MOA of Adenosine?
Stimulates P-1 purinergic receptor to open K channels; decreases Ca2 influx; decreases automaticity of and conduction through AV node
What are the EKG manifestations of Adenosine?
Short “flatline” prior to NSR
When would you use adenosine?
Emergency IV bolus to halt SVT
What are the side effects of Adenosine?
Vasodilation > hypotension; maybe brief bronchospasm
What is the MOA of Magnesium Sulfate?
Adds Mg2+ ions to counteract arrhythmias
When would you use Magnesium Sulfate?
Torsade de Pointes, digitalis-induced ventricular Arrhythmias, Mg-Deficient Arrhythmias
What are the side effects of Magnesium Sulfate?
Can cause other arrhythmias