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26 Cards in this Set
- Front
- Back
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MOA of Class I?
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Decrease fast Na channel (depolarization) & increase refractory period vs ADP
Na Channel Blockers - slow the rate and amplitude of phase 0 depolarization, reduces cell excitability, and reduces conduction velocity |
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MOA of Class IA?
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High potency as sodium channel blockers (prolong QRS interval), and also usually prolong repolarization (prolong QT interval) through blockade of potassium channels
Depress phase 0 (sodium-dependent) depolarization, thereby slowing conduction (less than class IC) Moderate potassium channel blocking activity (which tends to slow the rate of repolarization and prolong action potential duration) |
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Quinidine
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Treats ventricular and supraventricular arrhythmias
Quinidine preferred over procainamide SE: QTc - slowing of conduction – torsades de pointes, diarrhea, drug fever, thrombocytopenia, cinchonism Can ↑ ventricular response – control AV conduction first with BB, NDHP-CC, or Digoxin Correct electrolyte imbalances: ↓ K+ or Mg++ |
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Procainamide
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Treats ventricular and supraventricular arrhythmias
SE: hypersensitivity reactions (fever, rash), SLE, Agranulocytosis CI: can cause a drug induced lupus; has a lupus-like syndrome side effect, so contraindicated in patients with lupus |
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Disopyramide
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Alternative to quinidine and procainamide for treating ventricular arrhythmias
Proarrhythmic – torsades de pointes, v-tach, v-fib; anticholinergic effects Avoid in patients with HF, renal dysfunction and hepatic dysfunction |
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Class IB
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Lowest potency as sodium channel blockers, produce little if any change in action potential duration (no effect on QRS interval) in normal tissue, and shorten repolarization (decrease QT interval)
Have no effect on conduction velocity and may shorten APD More effective in tachyarrhythmias |
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Lidocaine
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Used for ventricular arrhythmias (VA), second line after amiodarone
Cardiac arrest, cardiac dysrhythmia, heart block, loss of consciousness, methemoglobinemia, seizure, tremor Use with caution in patients with CHF, renal or hepatic dysfunction |
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Phenytoin
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Most commonly used to treat digitalis-induced VA and SVA
Most commonly used as anticonvulsant SE: hypersensitivity reactions (liver, skin, and hematologic) Use with caution in patients with CHF, renal or hepatic dysfunction, respiratory depression, or hypotension |
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Mexiletine
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Effective against VA not responding to other therapy
SE: hypotension, bradycardia and nausea (improved with food) |
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Class IC
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Most potent sodium channel blocking agents (prolong QRS interval), and have little effect on repolarization (no effect on QT interval)
Slows conduction and may prolong APD (mild) ***Proarrhythmic activity Can ↑ ventricular response – control AV conduction first with BB, NDHP-CC, or Digoxin Don’t use in patients with structural heart disease |
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Flecainide
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Used to convert A. Fib; prevents PSVT; treats PVCs and ventricular tachycardia; reserved for refractory life- threatening VA who do not have CAD SE: CNS and GI
Significant inotropic effect and may worsen CHF |
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Propafenone
Moricizine |
Useful for resistant arrhythmias
Propafanone also has beta-blocking actions SE: dizziness is a significant side effect May cause new or worsened arrhythmias Avoid in patients with structural heart disease Requires close monitoring |
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Class II – Beta Blockers
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Blocks beta adrenergic receptors - inhibit sympathetic activity
Reduces sympathetic stimulation of the heart Slows conduction through the AV node Depress sinus node automaticity Lengthens the refractory period Heart rate slows, decreasing myocardial oxygen demand Effective alone or in combination with other antiarrhythmic agents for: ventricular tachycardia, premature ventricular contractions (PVCs), ventricular fibrillation, sinus tachycardia, atrial fibrillation, atrial flutter, atrial tachycardia. Beneficial in acute coronary syndrome where there exists high sympathetic tone Controls ventricular rate in A.Fib; terminates or prevents PSVT |
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Atenolol
Metoprolol |
Reduce the incidence of VF significantly in post-MI patients
SE: hypotension, bradycardia, cardiac arrest D/C by tapering over 3-7 days as sudden withdrawal may lead to acute MI, arrhythmias, or angina CI: sinus bradycardia, severe CHF, asthma |
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Esmolol
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Supraventricular arrhythmias (incl. PSVT) and rate control in A. fib after cardiac surgery
SE: hypotension occurs in 30% of patients, reversible by dosage reduction or D/C CI: severe LV failure, severe sinus bradycardia, hypoperfusion For short-term use only – replace with long-acting antiarrhythmic after heart stabilized |
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Class III
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Potassium channel blockers – prolong repolarization, refractory period, and action potential duration
Prolongs APD and has no effect on conduction |
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Amiodarone
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Controls ventricular and supraventricular arrhythmias
Most effective agent in preventing recurrences of A. fib and VT and VF Agent of choice if cardiac function impaired Supraventricular arrhythmia use: – Most effective anti-arrhythmic for maintenance of sinus rhythm in A. fib – Also offers ventricular rate control of rapid A. fib – Shown to reduce mortality, improve QOL, increase exercise tolerance Ventricular arrhythmia use – Control (treatment and prevention) of hemodynamically stable VT, polymorphic VT and wide-complex tachycardia – Increase survival with out-of-hospital VT – After defibrillation and epinephrine in cardiac arrest with persistent VT or VF – Adjunct to electrical cardioversion SE: peripheral neuropathy, pulmonary toxicity, especially in dose >400 mg/day, Corneal microdeposits form 1-4 months after initiating therapy, hepatic dysfunction, thyroid disorders, photosensitivity, bradyarrhythmias (torsades uncommon) CI: bradycardia |
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Bretyllium
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Solely to treat life-threatening refractory ventricular arrhythmias (VT and VF). Only given in ICUs. Not responsible for knowing Bretylium for exam; will not ask us anything about this drug on exam
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Sotalol
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Prevention of recurrences of A. fib; used with AICDs (Automatic Implanted Cardiac Difibrillators). Nonselective b-blocking activity; works by delaying atrial and ventricular repolarization SE: transient hypotension, bradycardia, myocardial depression, and bronchospasm
Side effects directly related to b-blockade and prolongation of repolarization CI: asthma, bradycardia |
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Dolfetilide
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Cardioversion of A.Fib/A. Flutter and to maintain NSR afterwards SE: headache, sinus tachycardia, and muscle cramps (uncommon due to pharmacologic selectivity)
Must be started in the hospital to monitor renal function and QT interval. Can induce or worsen ventricular arrhythmias (torsade de pointes) |
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Ibutilide
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Acute conversion of A. fib/flutter
Prolongs action potential and refractory period Minimal effects on BP and HR Relatively high incidence ventricular proarrhythmia (TdP) |
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Dronedarone
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Reduce the risk of cardiovascular hospitalization in patients with A. fib/flutter SE: GI: diarrhea/nausea – 5-9%, Renal: ≥10% increase in SCr in 51% of pts
CI: Concomitant use with strong CYP 3A4 inhibitors, bradycardia <50, concomitant use with other QTc prolonging medications – CI: oncomitant use with strong CYP 3A4 inhibitors, bradycardia <50, concomitant use with other QTc prolonging medications |
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Class IV – NDHP CCBs
Verapamil Diltiazem |
Inhibit AV node conduction by depressing the SA and AV nodes, where calcium channels predominate
Use: To treat Atrial Fibrillation/Flutter or Paroxysmal supraventricular tachycardia; Treatment and Prophylaxis Treat and prevent supraventricular arrhythmias Rapidly controls ventricular response to atrial flutter and fibrillation First line to suppress PSVTs from AV nodal re-entry SE: constipation, bradycardia, CHF worsening CI: atrial fibrillation/flutter associated with accessory bypass tract (Wolff-Parkinson-White, Lown-Ganong-Levine) or short PR syndromes, ventricular tachycardia, wide-complex (QRS 0.12 seconds or greater), Caution: CHF, SSS, hepatic/renal impairment, bradycardia, w/digoxin & beta-blockers |
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Digoxin
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Prolongs the refractory period of atrial tissue and reduces number of impulses conducted through AV node; positive inotropic effect, enhanced vagal tone, and decreased ventricular rate to fast atrial arrhythmias
Supraventricular arrythrmia- slows the ventricular rate in atrial fibrillation and atrial flutter Usually used with concomitant HF SE: GI, Ocular, CNS CI: Ventricular fibrillation |
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Atropine
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Blocks the action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands, and the CNS; increases cardiac output,
Therapeutic for symptomatic sinus bradycardia Promotes conduction through AV node and increases HR due to vagal blockade SE: Anticholinergic effects, hypertension, arrhythmias CI: narrow-angle glaucoma, obstructive gastrointestinal disease, ulcerative colitis or toxic megacolon , unstable cardiovascular status in acute hemorrhage or thyrotoxicosis |
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Adenosine
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Converts acute supraventricular tachycardia to normal sinus
Slows AV conduction, interrupts re-entry, restores normal sinus from PSVTs SE: Flushing, chest pain, brief period of asystole or bradycardia, hypotension CI: Poison/drug-induced tachycardia Less effective in pts taking theophylline / caffeine |
