Flashcards in Arrhythmia Deck (60)
How do anti-arrhythmic drugs generally work?
By affecting either specialized ion channels or sympathetic tone
What are the three main I-a class drugs? (Double Quarter Pounder)
What is the MOA of class I-a drugs?
Moderate block of both open Na+ and K+ channels
-slow phase 0 depolarization
-prolong action potential and slow conduction
What conditions do class I-a drugs treat?
Paroxysmal recurrent afib
Wolff-Parkinson-White syn. (procainamide)
What are the three I-b drugs? (Lettuce Pickles Mayo)
What is the MOA for class I-b drugs?
Mild blocking or inactivating Na+ channels
-shorten phase 3 repolarization
-decrease the duration of the action potential
What conditions do class I-b drugs treat?
What are the two I-c drugs? (Fries Please)
What is the MOA for class I-c drugs?
Block open Na+ channels
-markedly slow phase 0 depolarization
What conditions do class I-c drugs treat?
Paroxysmal atrial fibrilation
What is the class II drug?
What is the MOA of Propranolol (II)?
Block catecholamines at the AV node
-decrease slope of phase 4 depolarization
-prolong repolarization in AV node > block reentry
What conditions does Propranolol (II) treat?
What are the five class III drugs?
What is the MOA of Class III drugs?
Blocking IKr (rapid K+ delayed reaction, outflow)
-prolong phase 3 repolarization without altering phase 0
What conditions do class III drugs treat?
Wolff-Parkingons-White syn. (sotalol)
What makes Amiodarone different from other Class III drugs?
It blocks like other classes
Has a two month half-life
Treats atrial flutter, afib, vtach, vflutter, SVT
What are the class IV drugs?
What is the MOA of class IV drugs?
Block L-type Ca++ channels, decrease AV node conduction and increase refractory period
-similar to class II but does not block the adrenergic system
What conditions do the class IV drugs treat?
Prevent recurrence of paroxysmal supraventricular tachycardias
Control ventricular rate in afib
What treatments control rate?
Class II, IV, digoxin
What treatments control rhythm?
Class I-a, I-c, III
What are two nonpharmacologic treatments for rate and rhythm control?
Ablation and pacing
What are the drug interactions or contraindications for Quinidine?
Warfarin and digoxin
What are the drug interactions or contraindications for Disopyramide?
What are the drug interactions or contraindications for Mexiletine?
3rd degree AV block
What are the drug interactions or contraindications for Propafenone?
Heart failure, liver disease, valvular disease, CAD, Vtach
May increase digoxin concentrations
May decrease warfarin metabolism, BB properties
What are the drug interactions or contraindications for Flecainide?
Increased by haloperidol, cimetidine, fluoxetine
What are the drug interactions or contraindications for beta blockers?
Severe sinus bradycardia or heart block