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Flashcards in Arrhythmias II Deck (86):
1

What phase of AP = Automaticity?

phase 4

2

What phase of AP = conduction velocity

phase 0

3

What phase of AP = refractory period

phase 2 & 3

4

what phase of AP's do BB's effect?

Phase 4 (slows automaticity)
- also slows SAN & AVN

5

which node do CCB's slow more?

AVN> SAN

6

Mech of Class I antiarrhythmics

Na+ blockers

7

Class Ia anti arrhythmic and mech

Procainamide (Quinidine, Disopyramide)
Na+ blocker

8

Class Ib anti arrhythmic and mech

Lidocaine (IV) and Mexilitine (PO)
Na+ blockers

9

Class IC anti arrhythmic and mech

Flecainide and Propafenone
Na+ blockers

10

Mech of Class III antiarrhythmics

K+ blockers

11

Class III antiarrhythmics

Amio
Sotalol
(Ibutilide, Dofetilide, Dronedarone)

12

What phase do class I antiarrhythmics effect mainly?

Phase 0 (and 2 & 3)

13

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

QT prolonging
Renal dysfunction

14

Most common use for class Ia drugs

VT (monomorphic)
[also SVT]

15

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

Yes, better effect at faster HR

16

Do lido/mex effect QT?

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

17

2 cautions for lido/mex

CHF
Hepatic dysfunction

18

Which antiarrhythmics are the most potent Na+ blockers?

Class Ic (flecainide, Propafenone)

19

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

QRS (not QT)

20

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

Class Ic (flec/propafenone)

21

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

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

22

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

Can slow Aflutter and cause 1:1 AV conduction.
Use with AVN blockers

23

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

CAST

24

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

Phase 0, 3, 4.

25

can you get sinus brady with amio?

yes!

26

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

K+ channel blockers
Afib
VT

27

**Side effects of Class III drugs? Why?

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

28

What to monitor with Class III meds?

Renal dysfxn (contraindicated)
QT

29

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

Amio

30

Cardiac and Neuro side effects of Amio

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

31

Pulm/Thyroid/GI Side effects of Amio

pneumonitis/fibrosis
hyper/hypothyroidism
increased LFTs/nausea

32

Ocular/Derm side effects of Amio

corneal deposits
retinopathy
photosensitivity/blue skin

33

*Important Drug interactions w/ Amio

warfarin, Dig (have to decrease their dosing)
statins

34

Dronedarone indications and contraindications

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

35

Class IV agents, mech

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

36

what do Class IV CCB's do to AVN?

prolong conduction and refractoriness

37

Dig mech.

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

38

Best use for Dig

AF w/ RVR in CHF

39

what arrhythmia can dig overdose cause?

SVT
Bidirectional VT
PAT w/ variable AVB

40

*Adenosine mech

-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

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

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

Do nothing

42

*adenosine contraindication/indication

asthma/diagnose and treat SVT

43

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

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

44

which patients cannot get adenosine due to hypersensitivity?

OHT

45

Dig tox Rx?

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

46

atropine mech

acetylcholine blocker

47

atropine indications

bradycardia
AVB

48

ocular side effect of atropine

glaucoma

49

which gender is more likely to get a fib?

male

50

A/C protocol for AF DCCV

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

51

at CHADS=2, what is annual stroke rate?

4% (start A/C)

52

CHADSVASC score = CHADS of 2?

4

53

what age gets a point in CHADSVASC?

65

54

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

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

55

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

Dabigatran (Pradaxa)
No

56

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

-Factor Xa Inhibitor
- ROCKET-AF
- 20 BID
- Noninf. to warfarin/dec. ICH

57

how are the NOAGs mainly excreted?

renal and feces

58

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

-Factor Xa
- ARISTOTLE
-5 BID
-superioir to warfarin/marked dec. in major bleeding/dec. ICH

59

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

ICH

60

who do you rhythm control in a fib?

young
highly symptomatic
PAF
CHF from AF

61

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

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

62

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

Class III or ablation
(no flecainide/propafenone)

63

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

Class III/Ic drugs
**if bad LVH (>1.5cm thick): have to use AMIO or ablation

64

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

Amio
Dofetilife (not if on HD)
ablation

65

contraindicated meds in AF w/ bypass tracts

BB
CCB
Dig

66

Treatment for AF w/ bypass tracts

DCCV
PROCAINAMIDE
IBUTILIDE
sotalol
amio
ablation

67

why ablate AF?

sxs

68

which patients do you never send for AVN ablation?

young

69

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

1 procedure: 60-80%
2nd procedure: >80%

70

major complication rate s/p AF ablation?

2-12%

71

which pts do best after AF ablation?

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

72

ibutilide use and monitoring protocol?

-acute conversion of afib (better for AFl)
- >4hrs of monitoring QT.

73

at what QTc is dofetilide (Tikosyn) contraindicated?

440ms

74

what is the dosing algorithm for dofetilide accoridng to CrCl?

60ml/min: 500 BID

75

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

D/C dofetilide

76

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

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

77

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

Bradycardia
Hypomagnesemia
Hypokalemia

78

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

Yes

79

Antiarrhythmic to Rx torsades

Lidocaine

80

When is no anticoagulatuon or ASA OK in afib?

Age<60
No heart dz

81

HAS-BLED

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

82

What HAS-BLED score indicates high risk?

3

83

Which NOAG can actually reduce mortality c/t warfarin?

Apixaban

84

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

In CHF or Severe LVH (>1.5cm)

85

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 ?

Warfarin

86

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

No