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79 Cards in this Set
- Front
- Back
Which types of A-A's can be used for supraventricular arrhythmias?
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Class Ia, Ic, II, III, and IV
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Which types of A-A's can be used for ventricular arrhythmias?
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Class Ia,b,c, and III (bretylium- VF only)
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Whats the (pharmacological) definition of arrhythmia?
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abnormal impulse initiation, conduction, or both
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Class I blocks mainly what?
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Na+ channels
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Class II blocks mainly what?
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beta-blockade
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Class III blocks mainly what?
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K+ channels
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Class IV blocks mainly what?
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Calcium channels
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What are the class IA drugs (3)?
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quinidine, procainamide, and disopyramide
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What are the class 1B drugs (4)?
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Lidocaine, Mexiletine, tocainide, phenytoin (technically)
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What are the class 1C drugs (2)?
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Flecainide & propafenone
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What is the main difference of the subclasses of Class I A-A's?
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extent of Na+ blockade
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What are the general outcomes of Class I A-A actions?
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slow conduction time (dec. phase 0 slope, inc. QRS time), decrease automaticity (inc. threshold for AP), dec. phase 4 slope in pacemaker cells
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What class is Quinidine in and what are two common/characteristic AE's associated with it?
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Class IA; diarrhea, and Cinchonism (from tree bark; HA, dizziness, and tinnitus)
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What drugs can cause torsade de pointes (2)?
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quinidine and sotalol
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What electrolyte abnormalities can cause torsade de pointes (3)?
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hypo- kalemia, magnesemia, calcemia
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What A-A drug can decrease clearance of digoxin?
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Quinidine
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What drug can cause the AE, "lupus-like syndrome"?
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Procainamide
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What is the characteristic AE of procainamide?
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lupus-like syndrome
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Of class IA drugs, which has the most pronounced anti-cholinergic effects?
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disopyramide (> quinidine > procainamide)
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What grouping of AE's is common to disopyramide?
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anticholinergic effects (dry mouth, constipation, etc.)
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What is the MOA of lidocaine?
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"frequency dependent" rapid blockade of activated and inactivate (not resting) Na channels
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In what tissues does lidocaine have greatest effect?
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ischemic or rapidly driven tissues (purkinje fibers and ventricular cells)
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Do class IB A-A's affect AP duration?
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none to a little
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What clinical situations call for lidocaine?
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V-fib prevention after cardioversion, NOT for atrial arrhythmias
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What is the DOC for V-tach?
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Lidocaine
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What is the DOC for prevention of V-fib after cardioversion in acute MI?
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Lidocaine
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Why is lidocaine given only via IV?
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extensive first-pass metabolism
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What is the orally active derivative of lidocaine?
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mexilitine
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Which A-A drug is primarily used as an anticonvulsant?
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phenytoin of Class IB
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Which subclass of A-A has a STRONG inhibition of Na channels?
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Class IC
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What are the effects of class IC drugs on phase 0 depol, conduction, and AP duration
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marked depression of depol. in phase 0, slows conduction velocity in purkinje/ventricles, and has NO effect o AP duration
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What is the critical warning associated with flecainide use?
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treat SVT arrhythmias in pts. WITHOUT structural heart disease
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Which drug can be used as ORAL therapy in life-threatening ventricular arrhythmias?
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propafenone of class IC
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AE taste disturbance associated with what drugs?
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propafenone and moricizine
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What is the characteristic AE of propafenone?
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propafenone and moricizine
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Rank Class 1 subtypes in phase 0 depolarization depression
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IC > IA > IB
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Describe class I subtypes in respect to effect on repolarization
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IA- prolonged, IB- shortened, IC- no effect
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Describe class I subtypes in respect to AP duration
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IA- inc., IB- dec., IC- no effect
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What are the effects on ventricular AP by Class IA drugs?
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lengthen AP (via inc. repol)
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What are the effects on ventricular AP by Class IC drugs
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NONE
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Name 2 main effects of beta-blockers as A-A drugs? (hint: two effects of opposition of beta-adrenergic system)
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decrease contractility and decrease heart rate (via dec. automaticity of ectopic pacemakers)
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Beta blockers prolong the refractory period of AV node, preventing what?
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re-entry
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What class of A-A is the only one that decreases incidence of sudden death w/ previous MI?
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beta-blockers (class II)
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Which class II drug is good for short-term emergency tx of SVT's?
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esmolol
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What is a critical AE of class II A-A's?
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AV block
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What one drug fits into class II and Class III?
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sotalol
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What drug blocks K, Na, Ca, and beta-ads?
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amiodarone
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What drug can cause serious AV nodal block and bradycardia?
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amiodarone
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What are four common uses for amiodarone?
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1. sustained VT, 2. V-fib; 3. oral use for maintaining normal sinus rhythm in a-fib and (4.) for long-term management of SVT
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Pt. presents with asymptomatic AV block , rapid pulmonary fibrosis, and corneal midrodeposits. suspect what?
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amiodarone toxicity
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What are the 7 AE's of amiodarone? (hint?: 1 cardio, 1 resp, 2 eye, 1 endo, 1 metabolic, 1 neuro)
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asymptomatic AV block, rapid pulmonary fibrosis, corneal midrodeposits, hepatic dysfunction, neuromuscular symptoms, photosensitivity, and thryoid dysfunction
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amiodarone is structurally similar to what hormone?
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thryoxine
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What drug is a non-selective beta-blocker and K-channel blocker?
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sotalol
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What class of A-A's have dose-related AE of torsade de pointes?
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Class III (K)
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What mechanism leads to torsades de pointes?
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prolongation of QT interval
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What two Class III drugs are commonly used to convert a-fib or a-flutter to normal rhythm?
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Ibutilide and dofetilide
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Which CCB is likely to cause reflex tachycardia?
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nifedipine (b/c of marked vasodilation)
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Which CCB has the greatest cardiac effect?
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verapamil, then diltiazem
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What is the common complaint of pts on verapamil?
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constipation
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What CLASS (entire) of A-A's can increase serum digoxin?
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class IV (verapamil and diltiazem)
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What is the main A-A clinical use of CCB's?
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prevent nodal arrhythmias (SVT)
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What drug activates K+ channels, hyperpolarizing atrial tissues?
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adenosine
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What is the DOC for re-entrant arrhythmias (AVNRT, AVRT)?
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adenosine
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What are the 3 main effects of digoxin?
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1. positive inotrope
2. dec. automaticity via activation of the PSNS 3.slow AV node conduction |
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What are the two main clinical uses for digoxin?
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HF and A-fib
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What is the general therapeutic range of digoxin (in ng/ml)?
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0.5-0.8 ng/ml
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What are the 3 main general AE's of digoxin?
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GI (nausea, vomitting, diarrhea), CNS (yellow vision, HA,m dizzy), and arrhythmias (v-fib)
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What are 4 steps to Tx digoxin toxicity?
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hold digoxin, correct electrolyte abnormalities, emesis, and give digibind (Ab)
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First line of treatment for drug-induced torsade de pointes?
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Mg-sulfate
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1st line for PVCs?
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beta-blockers for symptomatic pt.
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1st line for NON-sustained V-tach?
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beta-blockers for symptomatic pt.
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1st line for sustained v-tach?
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lidocaine!
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1st line for V-fib?
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amiodarone
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DOC for a-fib/flutter rate control?
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CCBs, beta-blockers, digoxin
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DOC for pt. w/ a-fib and CHF?
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digoxin
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DOC to maintain sinus rhythm (5)?
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amiodarone, sotalol, flecainide, propafenon, dofetilide
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DOC for chronic AVNRT/AVRT?
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CCBs, BBs, fecainide, propafeonon, amiodarone, digoxin
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Two major AE's of adenosine?
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bronchospasm and shortness of breath
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Most likely choice of drug for a-fib/flutter rate control?
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diltiazem
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