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Pharmacology > Anti-Arrhythmias > Flashcards

Anti-Arrhythmias Flashcards

1
Q

Phase 4 of SA nodal cells

A

slow, spontaneous depolarization caused by an inward pacemaker current; these channels are relatively nonselective cation channels; K+ moves out of cells

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2
Q

Phase 0 of SA nodal cells

A

more rapid depolarization mediated by highly selective voltage-gated Ca++ channels that open to allow Ca++ in

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3
Q

Phase 3 of SA nodal cells

A

Ca++ channels slowly close and K+-selective channels open (K+ out), resulting in membrane repolarization

(there is also some involvement of Na+ channels closing during this phase)

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4
Q

Which phase define SA nodal cell firing

A

phase 4 –> phase 0 –> phase 3 –> phase 4, and so on

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5
Q

Phase 4 of ventricular myocytes

A

resting membrane potential; established by activation of time-independent K+ currents, which drive membrane potential close to K+ equilibrium potential

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6
Q

Phase 0 of ventricular myocytes

A

rapid depolarization; inward Na+ through voltage-gated Na+ channels

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7
Q

Phase 1 of ventricular myocytes

A

early phase of repolarization; decrease in outward Na+ d/t voltage-gated inactivation of sodium channels; and efflux of K+ ion through transiently opened K+ channels

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8
Q

Phase 2 of ventricular myocytes

A

plateau; balance between inward Ca++ thru Ca++ channels - both transient (T-type) and long-lasting (L-type) - and outward K+ through K+ channels

During this phase the cardiac cells are insulated electrically, allowing rapid propagation of AP w/ little current dissipation

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9
Q

Phase 3 of ventricular myocytes

A

late phase of rapid repolarization; decrease in inward Ca++ current and large increase in outward K+ current

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10
Q

Sinus tachycardia

A

supraventricular

rapid, but regular rate

increased sympathetic tone cz heart to race (100-160 bpm); depolarization originates from SA node

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11
Q

Atrial fibrillation

A

supraventricular

irregular rhythm

multiple ectopic foci of atrial cells generate 350-450 impulse per min; the ventricle responds to an occasional impulse

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12
Q

What is the MC type of SV arrhythmia?

A

Afib

risk is that blood becomes stagnant at times can can form clots; tx with anticoagulants

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13
Q

Atrial flutter

A

supraventricular

regular rhythm

atrial impulse reenters and depolarizes atrium; generates 250-350 impulse per min; ventricle responds to every 2nd or 3rd impulse

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14
Q

Multifocal atrial tachycardia

A

supraventricular

rate is rapid and irregular

depolarization originates from several atrial foci at irregular intervals; 100-200 bpm

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15
Q

premature atrial depolarization (PAT)

A

supraventricular

irregular rhythm

heat beats prematurely b/c a focus of atrial cells fires spontaneously before the SA node is ready to fire

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16
Q

sinus bradycardia

A

supraventricular

slow, but regular rhythm

increased parasympathetic (vagal) tone cz heart to beat at < 60 bpm; depolarization originates from SA node

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17
Q

A-V reentry

A

involves A-V junction
(notes say supraventricular)

AV node is split into a pathway that conducts twd the ventricle and a pathway that conducts the impulse back to the atrium; atrium and ventricles contract simultaneously; rate is 150-250/min

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18
Q

Wolf-Parkinson-White

A

involves A-V junction

impulses reaching the ventricle via the AV node circle back to the atrium via an accessory pathway that also links atrium to ventricles; this circuit may also be reversed; rate can exceed 300 bpm

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19
Q

Premature Ventricular Contractions (PVCs)

A

ventricular

spontaneous depolarization of ectopic focus in ventricle; benign if fewer than 6 per min.

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20
Q

Ventricular tachycardia

A

ventricular (duh!)

usu. 2’ to reentry circuit (i.e. AV reentry of WPW can progress to this)

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21
Q

Ventricular fibrillation

A

…ventricular

completely erratic

many ectopic foci in ventricle; rate is 350-350 bpm

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22
Q

What are some sx of arrhythmias?

A

palpitations, dizziness, SOB, chest pain, fatigue

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23
Q

What are some concerns with arrhythmias?

A

stroke, heart failure, sudden cardiac death

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24
Q

Vaughan-Williams class I drugs

A

Na+ channel blockers

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25
Q

Vaughan-Williams class Ia

A

have little effect on SA node automaticity (most anti-arrhythmic drugs do effect SA); moderate block of both Na+ and K+ channels; slow phase 0 depolarization; prolong AP and slow conduction

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26
Q

Vaughan-Williams class Ib

A

Mild blocking or inactivating Na+ channels; shorten phase 3 repolarization; decrease duration of AP

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27
Q

Vaughan-Williams class Ic

A

Block open Na+ channels; markedly slow phase 0 depolarization

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28
Q

Vaughan-Williams class II

A

antagonize adrenergic receptors (block catecholamines at AV node); decrease slope of phase 4 depolarization; prolong repolarization in AV node (block reentry)

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29
Q

Vaughan-Williams class III

A

tend to prolong phase 3 repolarization without altering phase 0

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30
Q

Vaughan-Williams class IV

A

block slow inward (L-type calcium channels) current; decrease AV node conduction and increase refractory period

(similar action to class II, but does not block adrenergic sx)

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31
Q

Class Ia drugs

A

Double Quarter Pounder

Disopyramide
Quinidine
Procainamide

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32
Q

Which type of arrhythmias can you tx with class Ia drugs?

A

1) ventricular tachycardia
2) Paroxysmal recurrent Afib
3) Wolff-Parkinson-White (procainamide)

33
Q

Class Ib drugs

A

Lettuce, Pickles, Mayo

Lidocaine
Phenytoin
Mexiletine

34
Q

Which type of arrhythmias can you tx with class Ib drugs?

A

ventricular tachycardias

35
Q

Class Ic drugs

A

Fries Please

Flecainide
Propafenone

36
Q

Which type of arrhythmias can you tx with class Ic drugs?

A

paroxysmal Afib

37
Q

Class II drugs

A

Propranolol (beta-blocker)

38
Q

Which type of arrhythmias can you tx with class II drugs?

A

sinus (SV) tachycardia

39
Q

Class III drugs

A 
Amiodarone
Sotalol
Ibutilide
Dofetilide
Dronedarone
40
Q

Which type of arrhythmias can you tx with class III drugs?

A

1) Wolff-Parkinson-White (sotalol)
2) Ventricular arrhyth.
3) Sinus tachycardia

41
Q

What is the half-life of amiodarone?

A

2 months

**be mindful of this when adding other medications

42
Q

Class IV drugs

A

Non-dihydropyridine
CCBs
Verapamil
Diltiazem

43
Q

Which type of arrhythmias can you tx with class IV drugs?

A

1) prevent recurrence of paroxysmal SV tachycardias

2) control ventricular rate in afib

44
Q

Which drugs work on rate control?

A

class II, class IV, and digoxin

**studies show that rate is a better way to target tx than rhythm

45
Q

Which drugs work on rhythm control?

A

class Ia, class Ic, class III

46
Q

Which drug is indicated for Afib, Aflutter, paroxysmal SVT, ventricular arrhythmias? Has drug interactions with warfarin and digoxin

A

Quinidine; Propafenone

47
Q

Which drug is indicated only for paroxysmal SVT, and is C/I in glaucoma?

A

Disopyramide

48
Q

Which drugs is indicated for ventricular arrhythmias and is commonly used as an add-on to amiodarone rather than as a sole agent. It is also C/I in 3rd degree AV block

A

Mexiletine

49
Q

Which drug has been seen to increase digoxin and is increased by haloperidol, cimetidine, and fluoxetine?

A

Flecainide

50
Q

Which drug is indicated for Afib, Aflutter, paroxysmal SVT, ventricular arrhythmias? C/I with severe sinus bradycardia or heart block?

A

Beta blockers

51
Q

Which drug is indicated for supraventricular and ventricular arrhythmias, but is C/I in iodine hypersensitivity, hyperthyroidism, and 3rd degree AV heart block? Also has DI with warfarin, digoxin, and statins

A

Amiodarone

52
Q

Which drug is indicated for paroxysmal or persistent Afib and Aflutter?

A

Dronedarone

53
Q

Which drug is indicated for ventricular arrhythmias and maintenance of Afib and Aflutter? But has a increased risk of arrhythmias with other antiarrhythmics

A

Sotalol

54
Q

Risk of proarrhythmia

A
  • higher in Class I
  • not in Class II

**dose-related with solatlol, Class IC, and N-acetyl procainamide (NAPA)

55
Q

Class Ia s/e

A

Anticholinergic effects

56
Q

Quinidine s/e

A

cardiac: negative inotropic, vagolytic, syncope, torsades

non-cardiac: cinchonism, GI, thrombocytopenia, DILE

57
Q

Type of pro-arrhythmia that demonstrates twisting of the QRS complex; **can result in sudden cardiac death

A

Torsades de pointes

58
Q

Procainamide s/e

A

cardiac: weak ganglionic blocking, NAPA metabolite

non-cardiac: DILE

59
Q

What is DILE?

A

drug induced lupus erythematosus

60
Q

Class Ib s/e

A

neurologic (stimulation or depression, convulsions)

61
Q

Lidocaine s/e

A

Non-cardiac: CNS excitation and/or depression, nausea, tremor, vertigo, metallic taste, numb lips, visual and hearing disturbances

**high concentrations > 9 mcg/mL may cz convulsions, respiratory depression, seizures

62
Q

Propafenone (Rhythmol) s/e

A

Cardiac: proarrhythmia in pt. with ischemic heart dz, beta-clocking leading to 1st or 2nd degree AVN blcok

Non-cardiac: metallic taste, dizziness

63
Q

When is Propafenone (Rhythmol) C/I?

A

heart failure stage III-IV, liver dz, valvular dz (torsades), CAD, VTach

64
Q

Propanolol s/e

A

bradycardia, hypotension, left ventricular HF, AVN block, bronchospasm

65
Q

Amiodarone s/e

A

corneal microdeposits (pt. need to get eyes checked), peripheral neuropathy, pulmonary fibrosis (rare), disturbed thyroid fn, photosensitivity w/ blue-gray discoloration (d/t iodine content); may precipitate HF, vary rare incidence of torsades

66
Q

Which drugs is similar to amiodarone but lacks iodine and thyroid s/e?

A

Dronedarone

67
Q

Sotalol s/e

A

non-selective beta-blockade (one enantiomer is a beta-blocker but other blocks Ikr (K+ channel)

Torsades

68
Q

Verapamil and Diltiazem s/e

A

Cardiac: negative inotropic, AVN block, sinus arrest

Non-cardiac: peripheral vasodilation, constipation, dizziness, flushing, HA, hypotension, gingival hyperplasia (benign but common)

69
Q

Adenosine MOA

A

acts of adenosine receptors (GPCR) to decrease adenylyl cyclase to decrease cAMP –> INCREASE potassium efflux –> cell hyperpolarization –> transient heart block of AV node

(this medication works w/in 15 seconds)

70
Q

Adenosine s/e

A

transient hypotension and chest pain

71
Q

Type(s) of arrhythmia(s) that Adenosine tx

A

1) AV re-entrant tachy

2) AV nodal re-entrant tachy

72
Q

Atropine MOA

A

competitive inhibitor of muscarinic acetylcholine receptors

73
Q

Type(s) of arrhythmia(s) that Atropine tx

A

bradycardia

74
Q

Atropine s/e

A

blurry vision, dry mouth, tachycardia

“dry as a bone, red as a beet, hot as a hare, blind as a bat, mad as a hatter”

75
Q

Atropine antidote

A

Physostigmine

given as slow IV injection of 1-4 mg (0.5-1 mg in kids) - rapidly abolishes delirium and coma cz by large doses of atropine

76
Q

Digoxin MOA

A

inhibit the Na+/K+ ATPase in the myocardium

  • decr. membrane sodium gradient
  • decr. sodium-calcium xchange
  • incr. intracellular Ca++
77
Q

Type(s) of arrhythmia(s) that Digoxin tx

A

1) Afib

2) Aflutter with RVR heart failure

78
Q

Digoxin s/e

A

bradycardia, partial or complete heart block, GI, drowsiness and fatigue, visual disturbances

Pharmacology (14 decks)

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