Antiarrhythmic Drugs

This is a brief overview of antiarrhythmic agents, or drugs used to resolve abnormal cardiac rhythms. I created this presentation with Google Slides. Image were created or taken from Wikimedia Commons I created this video with the YouTube Video Editor. ADDITIONAL TAGS Class IA antiarrhythmic agent Moderate sodium s, which s action potential duration Quinidine side effects blocks hERG , which results long QT and can cause torsades de pointes Procainamide Less prolongation QT segment, less TdP Disopyramide s force contraction heart Side effects: constipation, urinary retention, glaucoma IB antiarrhythmic Mild sodium s, which s action potential duration Lidocaine Intravenous only Mexiletine Can be administered orally IC antiarrhythmic Marked sodium s, doesn’t change action potential duration Flecainide Possibly produces an ventricular arrhythmias Propafenone Some beta er effects (bradycardia and cardiac inotropy) addition to changing AP duration by changing Na influx, Is also: phase 4 depolarization threshold potential sub degree Na+ AP duration change Beta-adrenergic receptor ers (beta ers) catecholamines (norepinephrine, epinephrine, dopamine) Reduces myocardial need for oxygen, can ischemia slope phase 4 depolarization s self-generated rhythmic firing heart (s automaticity) Prolong repolarization AV node → reentry Effectively s refractory period III antiarrhythmic s potassium s (delayed-rectifier potassium (DRK) s) Prolongs repolarization (phase 3) Amiodarone, Sotalol, Ibutilide, D etilide, Dronedarone III: Amiodarone Wide range effects through many mechanisms s sinus node firing s automaticity s reentrant circuits s Na, K, and Ca s ( I, III, IV antiarrhythmics) s alpha and beta ( II) adrenergic receptors → vasodilation and d intropy Treats many tachyarrhythmias: atrial flutter, atrial fibrillation, vtach, ventricular flutter, SVT Pharmacokinetically unique: absorbed slowly, deposits adipose tissue Half life 25-60 days → cannot easily diminish or reverse effects Side effects: pulmonary (pneumonia, pul fibrosis); cardiac (brady, arrhythmias, long QT, TdP); thyroid (due to iodine); GI; CNS Amiodarone Wide range effects through many mechanisms sinus node firing; s automaticity; s reentrant circuits; Na, K, and Ca alpha and beta adrenergic receptors vasodilation and intropy Treats many tachyarrhythmias: atrial flutter, atrial fibrillation, vtach, ventricular flutter, SVT Pharmacokinetically unique: absorbed slowly, deposits adipose tissue Half life 25-60 days Side effects: pulmonary (pneumonia, pul fibrosis); cardiac (brady, arrhythmias, long QT, TdP); thyroid (due to iodine); GI; CNS High rates torsades de pointes Dronedarone (amiodarone analog without iodine) Gastrointestinal side effects but not TdP Sotalol Calcium L-type Ca2+ Most effective cells dependant on Ca (SA, AV nodes) transmission through AV node (for rapid atrial pulses) Terminates reentrant rhythms Treats AV nodal reentrant tachycardia (primary treatment) Side effects: hypotension and heart failure pts taking beta-ers Diltiazem and Verapamil Digoxin Inhibits activity sodium potassium pump (Na+-K+ ATPase inhibitor) Treats heart failure complicated with atrial fibrillation (by decreasing heart rate) s vagal tone; reduces sympa tic activity Opens potassium (K+ activator) Intravenously with saline flush (short 10 s half life) Hyperpolarizes cells Allows for rapid termination reentrant supraventricular tachycardia chemical defibrillator