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Anti-Arrhythmias Flashcards

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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
Vaughan-Williams class Ia
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
26
Vaughan-Williams class Ib
Mild blocking or inactivating Na+ channels; shorten phase 3 repolarization; decrease duration of AP
27
Vaughan-Williams class Ic
Block open Na+ channels; markedly slow phase 0 depolarization
28
Vaughan-Williams class II
antagonize adrenergic receptors (block catecholamines at AV node); decrease slope of phase 4 depolarization; prolong repolarization in AV node (block reentry)
29
Vaughan-Williams class III
tend to prolong phase 3 repolarization without altering phase 0
30
Vaughan-Williams class IV
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)
31
Class Ia drugs
Double Quarter Pounder Disopyramide Quinidine Procainamide
32
Which type of arrhythmias can you tx with class Ia drugs?
1) ventricular tachycardia 2) Paroxysmal recurrent Afib 3) Wolff-Parkinson-White (procainamide)
33
Class Ib drugs
Lettuce, Pickles, Mayo Lidocaine Phenytoin Mexiletine
34
Which type of arrhythmias can you tx with class Ib drugs?
ventricular tachycardias
35
Class Ic drugs
Fries Please Flecainide Propafenone
36
Which type of arrhythmias can you tx with class Ic drugs?
paroxysmal Afib
37
Class II drugs
Propranolol (beta-blocker)
38
Which type of arrhythmias can you tx with class II drugs?
sinus (SV) tachycardia
39
Class III drugs
``` Amiodarone Sotalol Ibutilide Dofetilide Dronedarone ```
40
Which type of arrhythmias can you tx with class III drugs?
1) Wolff-Parkinson-White (sotalol) 2) Ventricular arrhyth. 3) Sinus tachycardia
41
What is the half-life of amiodarone?
2 months **be mindful of this when adding other medications
42
Class IV drugs
Non-dihydropyridine CCBs Verapamil Diltiazem
43
Which type of arrhythmias can you tx with class IV drugs?
1) prevent recurrence of paroxysmal SV tachycardias | 2) control ventricular rate in afib
44
Which drugs work on rate control?
class II, class IV, and digoxin **studies show that rate is a better way to target tx than rhythm
45
Which drugs work on rhythm control?
class Ia, class Ic, class III
46
Which drug is indicated for Afib, Aflutter, paroxysmal SVT, ventricular arrhythmias? Has drug interactions with warfarin and digoxin
Quinidine; Propafenone
47
Which drug is indicated only for paroxysmal SVT, and is C/I in glaucoma?
Disopyramide
48
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
Mexiletine
49
Which drug has been seen to increase digoxin and is increased by haloperidol, cimetidine, and fluoxetine?
Flecainide
50
Which drug is indicated for Afib, Aflutter, paroxysmal SVT, ventricular arrhythmias? C/I with severe sinus bradycardia or heart block?
Beta blockers
51
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
Amiodarone
52
Which drug is indicated for paroxysmal or persistent Afib and Aflutter?
Dronedarone
53
Which drug is indicated for ventricular arrhythmias and maintenance of Afib and Aflutter? But has a increased risk of arrhythmias with other antiarrhythmics
Sotalol
54
Risk of proarrhythmia
- higher in Class I - not in Class II **dose-related with solatlol, Class IC, and N-acetyl procainamide (NAPA)
55
Class Ia s/e
Anticholinergic effects
56
Quinidine s/e
cardiac: negative inotropic, vagolytic, syncope, torsades non-cardiac: cinchonism, GI, thrombocytopenia, DILE
57
Type of pro-arrhythmia that demonstrates twisting of the QRS complex; **can result in sudden cardiac death
Torsades de pointes
58
Procainamide s/e
cardiac: weak ganglionic blocking, NAPA metabolite non-cardiac: DILE
59
What is DILE?
drug induced lupus erythematosus
60
Class Ib s/e
neurologic (stimulation or depression, convulsions)
61
Lidocaine s/e
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
Propafenone (Rhythmol) s/e
Cardiac: proarrhythmia in pt. with ischemic heart dz, beta-clocking leading to 1st or 2nd degree AVN blcok Non-cardiac: metallic taste, dizziness
63
When is Propafenone (Rhythmol) C/I?
heart failure stage III-IV, liver dz, valvular dz (torsades), CAD, VTach
64
Propanolol s/e
bradycardia, hypotension, left ventricular HF, AVN block, bronchospasm
65
Amiodarone s/e
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
Which drugs is similar to amiodarone but lacks iodine and thyroid s/e?
Dronedarone
67
Sotalol s/e
non-selective beta-blockade (one enantiomer is a beta-blocker but other blocks Ikr (K+ channel) Torsades
68
Verapamil and Diltiazem s/e
Cardiac: negative inotropic, AVN block, sinus arrest Non-cardiac: peripheral vasodilation, constipation, dizziness, flushing, HA, hypotension, gingival hyperplasia (benign but common)
69
Adenosine MOA
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
Adenosine s/e
transient hypotension and chest pain
71
Type(s) of arrhythmia(s) that Adenosine tx
1) AV re-entrant tachy | 2) AV nodal re-entrant tachy
72
Atropine MOA
competitive inhibitor of muscarinic acetylcholine receptors
73
Type(s) of arrhythmia(s) that Atropine tx
bradycardia
74
Atropine s/e
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
Atropine antidote
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
Digoxin MOA
inhibit the Na+/K+ ATPase in the myocardium - decr. membrane sodium gradient - decr. sodium-calcium xchange - incr. intracellular Ca++
77
Type(s) of arrhythmia(s) that Digoxin tx
1) Afib | 2) Aflutter with RVR heart failure
78
Digoxin s/e
bradycardia, partial or complete heart block, GI, drowsiness and fatigue, visual disturbances

Pharmacology (14 decks)

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