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NAPLEX > Chapter 32: Arrhythmias > Flashcards

Chapter 32: Arrhythmias Flashcards

1
Q

What are the 3 ways an arrhythmia can be caused

A
  • The SA node can be firing at an abnormal rate or rhythm
  • Scar tissue from a prior heart attack can block and divert signal transmission
  • Another part of the heart may be acting as the pacemaker
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2
Q

What is used to diagnose arrhythmias

A

ECG

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3
Q

A ____ monitor is an ambulatory ECG device that records the heart’s electrical activity for 24-48 hours to detect intermittent arrhythmias

A

Holter

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4
Q

A normal sinus rhythm (NSR) beings in the ____ node

A

SA (the heart’s natural pacemaker)

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5
Q

Which pacemaker cells have automaticity, meaning they initiate their own action potential

A

SA (pacemaker) cells

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6
Q

In phase 0 of the action potential, rapid, ventricular depolarization initiates a heartbeat in response to influx of __, causing ventricular contraction

A

Na

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7
Q

In phase 2 of the action potential, there is a plateu in response to an influx of __ and efflux of ___

A

Ca

K

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8
Q

In phase 3 of the action potential, there is rapid ventricular repolarization in response to an efflux of __

A

K

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9
Q

The most common cause of arrhythmias

A

Myocardial ischemia or infarction

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10
Q

Which non-cardiac conditions can trigger or predispose a patient to arrhythmias

A
  • electrolyte imbalances (esp K, Mg, Na and Ca)
  • elevated sympathetic states (e.g., hyperthyroidism, infection)
  • drugs (including illicit drugs and antiarrhythmics)
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11
Q

What is the most common type of arrhythmia

A

AFib

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12
Q

In AFib, the atria are not able to adequately contract, leading to

A

blood stagnation in the atria, which increases the risk of clot formation. The clot can embolize to the brain and cause a stroke

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13
Q

Patients with AFib may require what medication class

A

Anticoagulants to reduce the risk of blood clots

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14
Q

Common ventricular arrhythmias include

A

Premature ventricular contractions (PVCs)

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15
Q

PVCs are referred to as

A

a skipped heart beat

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16
Q

In some people, PVCs can be related to

A

too much stress or caffeine, nicotine or exercise

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17
Q

A series of PVCs in a row, resulting in HR of > __ BPM, is known as ____

A

> 100 BPM

Ventricular tachycardia

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18
Q

Untreated ventricular tachy can degenerate into ____

A

Vfib (a medical emergency)

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19
Q

Which drug is used frequently for the treatment of Ventricular arrhythmias

A

IV lidocaine

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20
Q

Which key drugs can increase or prolong the QT interval

A
  • Antiarrhythmics: Class I (especially Class Ia) and Class III
  • Antibiotics: Quinolones and macrolides
  • Azole Antifungals: All except isavuconazonium
  • Antidepressants: TCAs (e.g., amitriptyline, clomipramine, doxepin); SSRIs (e.g., citalopram, escitalopram) – sertraline is preferred in cardiac patients; SNRIs, mirtazapine and trazadone
  • Antiemetic drugs: 5-HT3 RA, droperidol, and phenothiazines
  • Antipsychotics (most): chlorpromazine, clozapine, haloperidol, olanzapine, paliperidone, quetiapine, risperidone, thioridazine, ziprasidone
  • Other drugs: Donepezil, fingolimod, methadone, tacrolimus
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21
Q

Prolongation of the QT interval is a risk factor for ___, a particularly lethal ventricular tachyarrhythmia which can cause ____

A

TdP

sudden cardiac death

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22
Q

The risk of drug-induced QT prolongation increases with:

A
  • Higher doses
  • multiple QT-prolonging drugs
  • reduced drug clearance with renal or liver disease
  • drug interactions that decrease clearance (with enzyme inhibitors)
  • with hypokalemia and/or hypomagnesemia
  • other cardiac conditions
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23
Q

Which drugs are used in arrhythmias per Vaughan Williams Classification

A
  • Remember Double Quarter Pounder, Lettuce, Mayo, Fries Please! Because Dieting During Stress Is Always Very Difficult*
  • Class I
  • Ia: Disopyramide, Quinidine, Procainamide
  • Ib: Lidocaine, Mexiletine
  • Ic: Flecainide, Propafenone

-Class II: Beta-blockers

  • Class III
  • Dronedarone, Dofetalide, Sotalol, Ibutilide, Amiodarone

-Class IV: Verapamil, Diltiazem

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24
Q

What is rate control and which drugs are used for it

A

Patient remains in AFib and takes meds to control the ventricular rate (HR)
• BB or non-DHP CCBs (sometimes digoxin)

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25
Q

What is the goal for rhythm control and which drugs are used

A

Goal is to restore and maintain NSR

• Class Ia, Ic, or III antiarrhythmic or electrical cardioversion

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26
Q

If AFib is permanent, avoid ___-control antiarrhythmic drugs

A

rhythm

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27
Q

Which anticoags are preferred for non-valvular Afib

A

DOACs (e.g, apixaban, rivaroxaban)

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28
Q

The goal resting HR is < __ BPM in patients with symptomatic AFib, however, a more lenient rate-control strategy of < __ BPM may be reasonable in patients who are asymptomatic and have preserved LV function

A

80

110

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29
Q

Patients with HFrEF should NOT receive which drug class

A

non-DHP CCB

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30
Q

AFib has a high rate of thromboembolism. If the pt is not already using therapeutic anticoagulation, it should be started at least __ weeks before cardioversion & continued for at least __ weeks after successful cardioversion to NSR

A

3

4

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31
Q

Class I antiarrhythmics are ____ blockers

A

Na-channel

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32
Q

Class II antiarrhythmics are ____ blockers

A

Beta-blockers (remember: 2 Bs)

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33
Q

Class III antiarrhythmics are ____ blockers

A

K-channel

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34
Q

Class IV antiarrhythmics are ____ blockers

A

Calcium-channel (non-HDP)

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35
Q

Digoxin is a ____ blocker

A

Na-K-ATPase

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36
Q

Na-channel blockers have _____ inotrope potential, which ↓ the force of the heart’s contraction

A

Negative

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37
Q

Which 2 Calcium-channel blockers are preferentially used in HF

A

Amiodarone and dofetalide

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38
Q

Which medication is a beta-blocker but blocks K channels

A

Sotalol

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39
Q

MOA of digoxin

A

Decreases HR by enhancing vagal tone and increases force of contraction (positive inotrope)

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40
Q

Which drug class used for arrhythmias has a positive inotrope

A

Digoxin

41
Q

Which drug class used for arrhythmias has a negative inotrope

A

non-DHP CCBs

42
Q

Which drug is used for paroxysmal supraventricular tachyarrhythmias (PSVTs)

A

adenosine

43
Q

Amiodarone brand names

A

Nexterone, Pacerone

44
Q

Amiodarone BW

A
  • Pulmonary toxicity, hepatotoxicity

- For life-threatening arrhythmias only; proarrhythmic, must be hospitalized for IV loading dose

45
Q

Amiodarone CI

A

Iodine hypersensitivity

46
Q

Amiodarone warnings

A
  • Hyper- and hypothyroidism (hypo is more common) – amiodarone partially inhibits peripheral conversion of T4 to T3
  • optic neuropathy (visual impairment)
  • photosensitivity (slate-blue skin discoloration)
  • peripheral neuropathy
47
Q

Amiodarone SE

A

Hypotension, bradycardia, corneal microdeposits, photosensitivity

48
Q

Amiodarone infusions > __ hours require ____

A

2

non-PVC container (e.g. polyolefin or glass) - PVC tubing is OK

49
Q

Which amiodarone brand comes in a premixed bag, which has advantages like longer stability, non-PVC, non-DHP, in common concentrations

A

Nexterone

50
Q

Which antiarrhythmic is the DOC in HF

A

Amiodarone, dofetalide

51
Q

What should be done with amiodarone if hypotension or bradycardia occurs

A

Decrease infusion rate or d/c

52
Q

IV amiodarone: use ___ micron filter, ____ line preferred

A

0.22

central

53
Q

Amiodarone IV is incompatible with which drug

A

Heparin

54
Q

Amiodarone half-life

A

40-60 days

55
Q

Amiodarone is a CYP ___, ___, ___ and ___ inhibitor

A

2C9, 2D6, 3A4, P-gp

56
Q

When starting amiodarone, ↓ digoxin by ___% and ↓ warfarin by ___%.

A

50%

30-50%

57
Q

Do not exceed __ mg/day of simvastatin or __ mg/day of lovastatin with amiodarone; statin levels will increase

A

20

40

58
Q

Which drug can enhance the bradycardic effect of amiodarone and should not be used together

A

Sofosbuvir

59
Q

Diltiazem brand names

A

Cardizem, Cardizem CD, Cardizem LA, Cartia XT, Tiazac

60
Q

Verapamil brand name

A

Calan SR

61
Q

Non-DHP CCB warning

A

May worsen HF symptoms; do not use

62
Q

Side effects of non-DHP CCBs

A

Edema, arrhythmias, constipation (more with verapamil), gingival hyperplasia

63
Q

All CCBs are CYP ___ substrates

A

3A4

64
Q

Do not use ____ with any CCB

A

grapefruit juice

65
Q

Diltiazem and verapamil are ___ substrates and ___ inhibitors

A

P-gp substrates

3A4 inhibitors

66
Q

Patients who take which 2 statins with non-DHP CCBs should use lower doses or use a different statin

A

Simvastatin and lovastatin

67
Q

Digoxin brand names

A

Digitek, Digox, Lanoxin

68
Q

Typical dose of digoxin

A

0.125-0.25 mg PO daily

69
Q

Therapeutic range of digoxin for Afib

A

0.8-2 ng/mL (remember it is 0.5-0.9 for HF)

70
Q

Digoxin dose should be decreased or frequency should be decreased if CrCl < ___ mL/min

A

50

71
Q

When going from oral to IV digoxin, decrease the dose by __-__ %

A

20-25%

72
Q

Initial s/sx of digoxin toxicity

A

N/V, loss of appetite and bradycardia

73
Q

Severe s/sx of digoxin toxicity

A

blurred/double vision, greenish-yellow halos

74
Q

Digoxin is usually given with which two drug classes for rate control (not usually given alone)

A

BB or CCB

75
Q

Digoxin antidote

A

DigiFab

76
Q

Which electrolyte abnormalities can increase the risk of digoxin toxicity

A

Hypokalemia, hypomagnesemia, and hypercalcemia

77
Q

Disopyramide SE

A

Anticholinergic SE

78
Q

How should quinidine be taken

A

with food

79
Q

Quinidine warnings

A

Hemolysis risk (avoid in G6PD deficiency), can cause a positive Coombs test

80
Q

Quinidine SE

A

DILE, diarrhea (35%), stomach cramping (22%), cinchonism (e.g., overdose; sx include tinnitus, hearing loss, blurred vision, HA, delirium)

81
Q

Procainamide formulation

A

Injection

82
Q

What is the active metabolite of procainamide and how is it cleared

A

NAPA

Renally

83
Q

Procainamide therapeutic level

A

4-10 mcg/mL

84
Q

Procainamide BW

A
  • agranulocytosis

- Long-term use leads to positive antinuclear antibody (ANA), which can result in DILE

85
Q

Which two drugs used for arrhythmias can cause DILE

A

Quinidine and procainamide

86
Q

Metabolism of procainamide to NAPA occurs by ____

A

acetylation (slow acetylators are at risk for drug accumulation and toxicity)

87
Q

Lidocaine injection is used for

A

Refractory VT/cardiac arrest

88
Q

Flecainide, propafenone CI

A

HF, MI

89
Q

propafenone SE

A

metalic tase disturbance

90
Q

Dronedarone BW

A

Increased r/o death, stoke and HF in pts with decompensated HF or permanent AFib

91
Q

Dronedarone CI

A

Concurrent use of strong 3A4 inhibitors and QT-prolonging drugs

92
Q

Dronedarone warnings

A

Hepatic failure, pulmonary disease (including pulmonary fibrosis)

93
Q

Dronedarone SE

A

QT prolongation

94
Q

T/F: Dronedarone does not contain iodine and has little effect on thyroid function

A

True

95
Q

Decrease frequency of sotalol with CrCl < __ mL/min

A

60

96
Q

Which drug do you need to correct hypokalemia and hypomagnesemia prior to use and throughout treatment

A

Ibutilide

97
Q

Which antiarrhythmic must be initiated in a setting with continuous ECG monitoring

A

Dofetalide

98
Q

Which antiarrhythmic needs assessment of CrCl for a minimum of 3 days

A

Dofetalide

99
Q

Adenosine half-life

A

less than 10 seconds

NAPLEX (74 decks)

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