Arrhythmias II Flashcards

1
Q

What phase of AP = Automaticity?

A

phase 4

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2
Q

What phase of AP = conduction velocity

A

phase 0

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3
Q

What phase of AP = refractory period

A

phase 2 & 3

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4
Q

what phase of AP’s do BB’s effect?

A
Phase 4 (slows automaticity)
- also slows SAN & AVN
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5
Q

which node do CCB’s slow more?

A

AVN> SAN

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6
Q

Mech of Class I antiarrhythmics

A

Na+ blockers

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7
Q

Class Ia anti arrhythmic and mech

A

Procainamide (Quinidine, Disopyramide)

Na+ blocker

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8
Q

Class Ib anti arrhythmic and mech

A

Lidocaine (IV) and Mexilitine (PO)

Na+ blockers

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9
Q

Class IC anti arrhythmic and mech

A

Flecainide and Propafenone

Na+ blockers

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10
Q

Mech of Class III antiarrhythmics

A

K+ blockers

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11
Q

Class III antiarrhythmics

A

Amio
Sotalol
(Ibutilide, Dofetilide, Dronedarone)

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12
Q

What phase do class I antiarrhythmics effect mainly?

A

Phase 0 (and 2 & 3)

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13
Q

What to watch out for w/ class Ia drugs (procainamide, disopyramide, quinidine)

A

QT prolonging

Renal dysfunction

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14
Q

Most common use for class Ia drugs

A

VT (monomorphic)

[also SVT]

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15
Q

are class Ib (lido/mex) use dependent? What does that mean?

A

Yes, better effect at faster HR

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16
Q

Do lido/mex effect QT?

A

No!
Can use for afterdepolarizations (dig-induced VT)
Can use for torsades

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17
Q

2 cautions for lido/mex

A

CHF

Hepatic dysfunction

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18
Q

Which antiarrhythmics are the most potent Na+ blockers?

A

Class Ic (flecainide, Propafenone)

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19
Q

Because they are the most potent Na+ blockers, what widens on ECG with Propafenone/flec?

A

QRS (not QT)

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20
Q

Used for a fib or refractory SVTs (refused ablation, other meds didn’t work)?

A

Class Ic (flec/propafenone)

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21
Q

When is mortality increased with Class Ic (flec/propafenone)

A

structural heart dz (LV dysfxn, LVH, MI, ischemia)

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22
Q

what is a common/serious pro arrhythmic effect of class Ic? what is the Rx for it?

A

Can slow Aflutter and cause 1:1 AV conduction.

Use with AVN blockers

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23
Q

which trial showed that class Ic meds (flecainide, propafenone) had increased mortality with structural heart dz?

A

CAST

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24
Q

Even thoughts it a Class III (phase 3), what phases of AP does Amio effect?

A

Phase 0, 3, 4.

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25
Q

can you get sinus brady with amio?

A

yes!

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26
Q

What is mech of class III? What are its 2 clinical uses?

A

K+ channel blockers
Afib
VT

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27
Q

**Side effects of Class III drugs? Why?

A

Long QT/Torsades;, exacerbated by hypo Mg/K. Reverse-use dependence (works at slower HR—> torsades)

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28
Q

What to monitor with Class III meds?

A
Renal dysfxn (contraindicated)
QT
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29
Q

most effective drug for preventing recurrent AF and for VT/VF?

A

Amio

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30
Q

Cardiac and Neuro side effects of Amio

A
bradycardia
Long QT/Torsades
Hypotension
ATAXIA (falling)
TREMOR 
NEUROPATHY
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31
Q

Pulm/Thyroid/GI Side effects of Amio

A

pneumonitis/fibrosis
hyper/hypothyroidism
increased LFTs/nausea

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32
Q

Ocular/Derm side effects of Amio

A

corneal deposits
retinopathy
photosensitivity/blue skin

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33
Q

*Important Drug interactions w/ Amio

A

warfarin, Dig (have to decrease their dosing)

statins

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34
Q

Dronedarone indications and contraindications

A

Indication: PAF w/ 1 assoc. risk factor (age, HTN, LA>5cm, EF<40%)
Contraindication: Chronic AF- inc. mortality/CVA/HF!
Acute/severe CHF
cirrhosis

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35
Q

Class IV agents, mech

A

diltiazem
verapamil
L-type CCB’s (phase 0 and 4)

36
Q

what do Class IV CCB’s do to AVN?

A

prolong conduction and refractoriness

37
Q

Dig mech.

A

1) BLOCKS Na-K ATPase -> increases intracellular Ca–>inotropy
2) increases vagal tone in central CNS
3) decreases AVN conduction/increases refractoriness

38
Q

Best use for Dig

A

AF w/ RVR in CHF

39
Q

what arrhythmia can dig overdose cause?

A

SVT
Bidirectional VT
PAT w/ variable AVB

40
Q

*Adenosine mech

A
  • binds to Adenosine (A1) receptor
  • causes compete AVB transiently (dec. cAMP–> dec Ca/Na into cells)
  • reduces automaticity (hyperpolarizes cell men by inc. K+ outward)
41
Q

*what is adenosine’s action in the atria? What is Rx?

A

shortens atrial refractoriness–> propensity for AF (b/c of inc’d outward K+ flow).

Do nothing

42
Q

*adenosine contraindication/indication

A

asthma/diagnose and treat SVT

43
Q

*adenosine response for:
AVNRT/AVRT
Focal AT
AF/Flutter

A

AVNRT/AVRT - terminates
Focal AT- AV block can inc./doesnt usu. terminate
AF/Flutter- unmasks AF/FL/AVB can inc.

44
Q

which patients cannot get adenosine due to hypersensitivity?

A

OHT

45
Q

Dig tox Rx?

A

Digibind

Do NOT check dig levels after (they will be very high)

46
Q

atropine mech

A

acetylcholine blocker

47
Q

atropine indications

A

bradycardia

AVB

48
Q

ocular side effect of atropine

A

glaucoma

49
Q

which gender is more likely to get a fib?

A

male

50
Q

A/C protocol for AF DCCV

A

TEE-guided or 3 weeks w/ INR>2.

51
Q

at CHADS=2, what is annual stroke rate?

A

4% (start A/C)

52
Q

CHADSVASC score = CHADS of 2?

A

4

53
Q

what age gets a point in CHADSVASC?

A

65

54
Q

Dabigatran (Pradaxa) mech/trial/dose/M&M

A
  • direct thrombin inhibitor
  • RE-LY
  • 150 BID
  • superior to warfarin (dec mortality, ICH) but more GIB
55
Q

which NOAG is potentially dialyzable? does it have a reversal agent?

A

Dabigatran (Pradaxa)

No

56
Q

Rivaroxaban (Xarelto) mech/trial/dose/M&M

A
  • Factor Xa Inhibitor
  • ROCKET-AF
  • 20 BID
  • Noninf. to warfarin/dec. ICH
57
Q

how are the NOAGs mainly excreted?

A

renal and feces

58
Q

Apixaban (Eliquis) mech/trial/dose/M&M

A
  • Factor Xa
  • ARISTOTLE
  • 5 BID
  • superioir to warfarin/marked dec. in major bleeding/dec. ICH
59
Q

what type of bleeding do all the NOAGs decrease c/t warfarin?

A

ICH

60
Q

who do you rhythm control in a fib?

A

young
highly symptomatic
PAF
CHF from AF

61
Q

if no cardiac dz, what antiarrhytmics do you use for a fib?

A
Class III (all but ibutilide: dronedarone/sotalol/amio for refractory AF/dofetilide
Class Ic (flecainide/propfenone)
62
Q

if pt. has CAD, best rhythm control strategy for AF?

A

Class III or ablation

no flecainide/propafenone

63
Q

If pt. has HTN, best rhythm control strategy for AF?

A

Class III/Ic drugs

**if bad LVH (>1.5cm thick): have to use AMIO or ablation

64
Q

*if pt. has CHF, rhythm control strategy for AF?

A

Amio
Dofetilife (not if on HD)
ablation

65
Q

contraindicated meds in AF w/ bypass tracts

A

BB
CCB
Dig

66
Q

Treatment for AF w/ bypass tracts

A
DCCV
PROCAINAMIDE
IBUTILIDE
sotalol
amio
ablation
67
Q

why ablate AF?

A

sxs

68
Q

which patients do you never send for AVN ablation?

A

young

69
Q

AF ablation success rates after 1st and 2nd procesure?

A

1 procedure: 60-80%

2nd procedure: >80%

70
Q

major complication rate s/p AF ablation?

A

2-12%

71
Q

which pts do best after AF ablation?

A
young, 
very symptomatic, 
PAF, 
normal EF, 
LA < 5cm, 
no pulm dz/OSA.
72
Q

ibutilide use and monitoring protocol?

A
  • acute conversion of afib (better for AFl)

- >4hrs of monitoring QT.

73
Q

at what QTc is dofetilide (Tikosyn) contraindicated?

A

440ms

74
Q

what is the dosing algorithm for dofetilide accoridng to CrCl?

A

60ml/min: 500 BID

75
Q

what happens if, after 2nd dose of dofetilide, QTc>500ms

A

D/C dofetilide

76
Q

after checking QTc 2h after dofetilide, what is protocol?

A

if QTc inc’d >15% or is >500ms, decrease dose

77
Q

Name 3 factors that can make a prolonged QT turn into torsades

A

Bradycardia
Hypomagnesemia
Hypokalemia

78
Q

Do you treat torsades with IV mag even if Mag level is normal?

A

Yes

79
Q

Antiarrhythmic to Rx torsades

A

Lidocaine

80
Q

When is no anticoagulatuon or ASA OK in afib?

A

Age<60

No heart dz

81
Q

HAS-BLED

A
HTN (uncontrolled)
Abnormal liver or kidneys (Cr>2.6)
Stroke
Bleeding
Labile INR
Elderly (>65)
drugs or alcohol
82
Q

What HAS-BLED score indicates high risk?

A

3

83
Q

Which NOAG can actually reduce mortality c/t warfarin?

A

Apixaban

84
Q

When is Amio a first line agent as an antiarrhythmic in afib?

A

In CHF or Severe LVH (>1.5cm)

85
Q

If a pt with multiple comorbidities (76y, HTN, DM, etc) comes in to clinic with afib and sxs but stable, what is your initial recommendation ?

A

Warfarin

86
Q

Are lidocaine or Ibutilide in the algorithm for antiarrhythmic treatment of afib?

A

No