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DNURS 836 Advanced Pharmacology for Anesthesia II > Antiarrhythmics - Quiz 4 > Flashcards

Antiarrhythmics - Quiz 4 Flashcards

1
Q

What happens in Phase 0 of the Cardiac Action Potential?

A

At -70mV, Na+ rushes in and causes Ventricular Contraction until +65mV when the Na+ channels inactivate

Phase 0:
Voltage-gated Na+ channels: Na+ flush into the cell  Rapid depolarization

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2
Q

What happens in Phase 1 of the Cardiac Action Potential?

A

Early Rapid Repolarization
Phase 1:
Voltage-gated K+ channels: Inactivation of Voltage gated Na+ channels and activation of voltage gated K+ channels that will leak K+ out of the cell
–>Initial repolarization.

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3
Q

What happens in Phase 2 of the Cardiac Action Potential?

A

Plateau

Slow Ca2+ Influx balances out K+ Efflux and maintains +10 to -20 mV

Phase 2:
L-type Ca++ channels: Allow Ca++ to go into the cell while K+ keeps leaking out of it –>Plateau.
Ca++ release from sarcoplasmic reticulum and myocyte contraction (coupling).

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4
Q

What happens in Phase 3 of the Cardiac Action Potential?

A

Rapid Repolarization

Inactivated Ca2+ Channels & BIG K+ Efflux

Phase 3:
Closure of Voltage-gated Ca++ channels
Opening of voltage-gated slow delayed-rectifier K+ channels: Massive K+ efflux –>Rapid repolarization

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5
Q

What happens in Phase 4 of the Cardiac Action Potential?

A

Spontaneous Depolarization

ATP Pumps resets all electrolytes back

Phase4:
High K+ efflux through K+ channels –>Resting state.

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6
Q

What is the diference between Muscle Cell Action Potentials & Automatic SA/AV Cell Action Potentials?

A

Muscle Cell: Sodium-Dependent Deplarization

SA/AV Cell: Calcium-Dependent Depolarization

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7
Q

How does an Automaticity Reduction in the Higher Pacemaker Sites affect the Lower Pacemaker Sites?

A

Automaticity will favor Lower Pacemaker Sites

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8
Q

What factors reduce the automaticity of higher pacemaker sites?

A

Vagal Responses

Digitalis Drugs

Parasympathomimetics

Halothane

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9
Q

What causes Ectopic Foci?

A

Enhanced Automaticity near the SA Node

Sympathomimetics

Hypercarbia

Hypoxia

Dig. Toxicity

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10
Q

What can cause Arrythmias from Re-Entry?

A

Unidirectional Impulse Block from Injury

&

Alternate Pathway

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11
Q

In regards to Arrhythmias, where can Re-Entry occur?

A

SA

AV

Atrium

Ventricle

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12
Q

What are Type I Antiarrhythmics?

A

Na+ Channel Blockers - Slows Conduction & Prolongs QRS

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13
Q

What are Type IV Antiarrhythmics?

A

Ca2+ Channel Blockers -

Slows Atrial Rate via SA Node

&

Slows Conduction via AV Node prolonging P-R Interval

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14
Q

What are Type III Antiarrhythmics?

A

K+ Channel Blockers -

Slows Conductions & ↑Refractory Period to prolong QT Interval

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15
Q

What meds are Class Ia Antiarrhythmics and how do they affect the Action Potential?

A

Slows 0 & Prolongs 3 - Blocks Na+ & K+ Channels

Quinidine

Procainamide

Disopyramide

Moricizine

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16
Q

What meds are Class Ib Antiarrhythmics and how do they affect the Action Potential?

A

Slows 0 & Shortens 3

Lidocaine

Mexilitine

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17
Q

What meds are Class Ic Antiarrhythmics and how do they affect the Action Potential?

A

Very Slow Phase 0 - Potent Na+ Channel Blocker

Flecainide

Propafenone

MOST PRO-ARRHYTHMIC

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18
Q

What meds are Class II Antiarrhythmics and how do they affect the Action Potential?

A

Reduces Phase 4 Slope - ↓Depolarization Rate

Beta-Blockers

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19
Q

What meds are Class III Antiarrhythmics and how do they affect the Action Potential?

A

Prolongs Phase 3 - Inhibits K+ Channels

Amiodarone

Dronedarone

Sotalol

Ibutilide

Dofetilide

Bretylium

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20
Q

What meds are Class IV Antiarrhythmics and how do they affect the Action Potential?

A

Reduces Phase 4 Slope - Inhibits Slow Ca2+ Channels

Diltiazem

Verapamil

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21
Q

Although Amiodarone & Sotalol are Class III Antiarrhythmics that Block K+ Channels, what other channels do they block?

A

Na+ (Class I)

Beta Receptors (Class II)

Ca2+ (Class IV)

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22
Q

Which class of Antiarrhythmics do Adenosine & Digoxin belong to?

A

Unclassified

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23
Q

How does Procainamide work?

A

Ia Antiarrhythmic

Blocks Na+ & K+ Channels

Converts Unidirectional to Bidirectional Blcok to prevent Re-Entry

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24
Q

What type of Arrhythmias does Procainamide treat?

A

Any type of Arrhythmia

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25
Q

What is the concern when giving Procainamide?

A

Myocardial Depression

Hypotension

QT Prolongation

Heart Block

Ventricular Ectopy

Lupus

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26
Q

What the risk of giving multiple doses of Procainamide?

A

NAPA Metabolite w/ Longer half-life & MORE cardiac side effects

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27
Q

How does Quinidine work?

A

Ia Antiarrhythmic

↑Excitability Threshold

↓Automaticity

Prolongs Action Potential & Refractory

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28
Q

Why does Quinidine also cause Hypotension, Tachycardia, and Atrial Arrhythmias?

A

It also has Alpha Blockade effects & Vagal Inhibition

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29
Q

When is Quinidine indicated?

A

A-Fib/Flutter

&

V-Fib/V-Tach

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30
Q

What are signs of Quinidine Toxicity?

A

QT Prolongation

V-Tach

Diarrhea

Thrombocytopenia

Cinchonism (Tree Bark) - Heachache & Tinnitus

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31
Q

How does Lidocaine Work?

A

Ib Antiarrhythmic

Blocks Na+ Channels

↓Phase 0 Slope & reduce Automaticity

Used for V. arrhythmias, particularly reentry dysrhythmias

No effect on QT

toxicity: nystagmus and speech changes

32
Q

How does Disopyramide compare to the other Ia Antiarrhythmics?

A

Same as Quinidine, but WITHOUT Alpha Effects and WITH Anticholinergic Effects

33
Q

What are signs of Disopyramide Toxicity?

A

Acute CHF

QT Prolongation

Thrombocytopenia

Anticholinergic Side Effects

34
Q

When is Lidocaine used?

A

Ventricular Arrhythmias

&

Re-Entry Dysrhythmias

(NOT effective for SVT)

35
Q

What are the side effects of Lidocaine?

A

Depression to Seizure

LV Dysfunction

Nystagmus

Speech Changes

Does NOT prolong QT

36
Q

When should Lidocaine dosages be reduced?

A

In patients w/ CHF & Liver Disease

37
Q

How does Phenytoin work as an Antiarrhythmic?

A

Ib Antiarrhythmic

Blocks Na+ Channels

Stops Digitalis-Induced Dysrhythmias

38
Q

What happens if Phenytoin is given too quickly?

A

Respiratory Arrrest

Hypotension

Ventricular Ectopy

Death

39
Q

What are the CNS effects of Phenytoin?

A

Drowsiness

Nystagmus

Nausea

Vertigo

40
Q

How does Flecainide Work?

A

Ic Antiarrhythmic

Blocks Na+, K+, & Ca2+ Channels

↓Phase 0

Supresses SA node like B-Blockers & CCBs

41
Q

What are indications for Flecainide?

A

PVCs

Wolf-Parkinsons White

Atrial Tachydysrhthmias

42
Q

When should Flecainide NOT be used due to its Negative Inotropic Effects?

A

CAD

LV Failure

V-Tach

43
Q

How do Beta-Blockers work as Anti-Arrhythmics?

A

Type II Antiarrythmic

Britton: Beta blockade leads to slowing of the S-A node (decreased slope of phase 4 depolarization)
Slow the rate depolarization of ectopic pacemakers
Prolonged A-V nodal conduction
Increased refractoriness of A-V node

↓Phase 4
Therefore, β-blockers decrease the conduction velocity of action potentials throughout the AV node
decreases the slop of phase 4 and slower phase zero in AV node
Rate control in a fib aflutter and svt

44
Q

What are the side effects of Flecainide?

A

Vertigo

Vision Problems

Highly Pro-Arrhythmic

45
Q

Which arrhythmias are Beta-Blockers used for?

A

SVT

A-Fib/Flutter

NO Ventricular Arrythmias Effects

46
Q

What does Amiodarone do?

A

Type III Anti-Arrhythmic

Blocks Na+, K+, Ca2+ Channels

Blocks Abnormal Automaticity

Anti-Adrenergic (Alpha & Beta)

Converts Atrial Arrhythmias to NSR

Prolongs PR, QRS, & QT

47
Q

What kind of Arrhythmias does Amiodarone treat?

A

Recurrent V-Fib

Unstable V-Tach

Wolf-Parkinsons White

Atrial Arrhythmias

48
Q

What happens to the Half-Life of Amiodarone when there is prolonged use?

A

Half-Life Increases

49
Q

How does Amiodarone affect Anticoagulants?

A

Increases INR & Bleeding

50
Q

How does Amiodarone affect Meds that Prolong QT?

A

Futher Prolongs QT and causes Torsades

51
Q

How does Amiodarone affect Digoxin & Lidocaine?

A

Increases Toxicity of Both

52
Q

How does Amiodarone affect Statins?

A

Increases Myalgias

53
Q

How does Amiodarone affect Suggamadex & AV Nodal Blockers?

A

↑Bradycardia

↑AV Block

Sinus Arrest

54
Q

How does Amiodarone affect Versed?

A

Prolongs Sedation

&

↑Respiratory Depression

55
Q

What are the Respiratory complications from Amiodarone?

A

ARDS

&

Pulmonary Fibrosis

56
Q

What are the CV complications from Amiodarone?

A

Bradycardia

Hypotension

Dysrhythmias

Heart Failure

Heart Block

Sinus Arrest

57
Q

How does Amiodarone affect the Liver?

A

Elevated LFTs

&

Liver Failure

58
Q

What are the Endocrine complications from Amiodarone?

A

Hyper/Hypothyroidism

59
Q

What is Dronedarone?

A

PO med
Indication: For atrial fibrillation to maintain NSR

60
Q

Why is Dronedarone not used in patients w/ Heart Failure or Permanent A-Fib?

A

Worsens HF

↑Stroke

↑Death

61
Q

When is Dronedarone contraindicated?

A

2nd & 3rd Degree Blocks

Prolonged QT

Pregnancy

Liver Disease

62
Q

What is Ibutilide/Dofetilide?

A

Class III Antiarrhythmic used to convert A-Fib

63
Q

What is the main Complication of Ibutilide/Dofetilide??

A

Torsades & V-Tach

Class III
Used for conversion of atrial fibrillation to NSR
High incidence of Torsades and ventricular tachyarrythmias

64
Q

How does Verapamil work as an Antiarrhythmic?

A

Class IV that blocks slow Ca2+ channels to prolong SA & AV Nodal Conduction

65
Q

Which arrhythmias is Verapamil used for?

A

Atrial Arrhythmias

SVT

NO effects on accessory paths

66
Q

What are Verapamil’s side effects?

A

Hypotension

Bradycardia

Asystole

67
Q

How does Diltiazem compare to Verapamil as an Antiarrhythmic?

A

Same, but less significant and MORE DRUG INTERACTIONS

68
Q

What kind of Arrhythmias does Digoxin treat?

A

Atrial Arrythmias

69
Q

When is use of Digoxin as an Antiarrhythmic contraindicated?

A

Accessory Pathways - WPW Syndrome

70
Q

How does Adenosine work?

A

Activates K+ channels for Nodal Hyperpolarization causing a transient 3rd degree block and increases refractory

71
Q

What do the A1 Adenosine receptors do?

A

Negative Dromotrope

&

Beta Sympatholytic

72
Q

What do the A3 Adensoine receptors do?

A

Negative Inotrope & Dromotrope

73
Q

When is Adenosine used?

A

Paroxysmal SVT (including accessory pathways)

NO effect on A-Fib/Flutter or Arrhythmias distal to AV Node

74
Q

Which class of Anti-Arrhythmic is most likely to cause Torsades?

A

Class Ia & III - blocks K+ channels & prolongs QT

75
Q

What NON Antiarrhythmic meds prolong QT Intervals?

A

Antipsychotics

Diuretics

Antifungals

Methadone

Aricept

Anesthetic Gas

Nausea Meds

76
Q

Which antibiotics prolong QT intervals?

A

Macrolides

&

Fluoroquinolones

77
Q

Which Class of Antiarrhythmics might be the cause of Incessant V-Tach?

A

1a & 1c

DNURS 836 Advanced Pharmacology for Anesthesia II (12 decks)

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