Anti-Arrhythmics Flashcards

1
Q

what’s the goal of arrhythmia drugs?

A

reduce ectopic pacemaker activity
modify conduction or refractory to disable reentry

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2
Q

what do class I anti-arrhythmics do?

A

block Na+ channels

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3
Q

what do class IA anti-arrhythmics do?

A

blocks OPEN/ACTIVATED Na+ channels

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4
Q

what do class IB anti-arrhythmics do?

A

blocks INACTIVE Na+ channels

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5
Q

what do class IC anti-arrhythmics do?

A

blocks both open and closed Na+ channels

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6
Q

what do class II anti-arrhythmics do?

A

reduce adrenergic activity of heart

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7
Q

what do class III anti-arrhythmics do?

A

K+ channel block

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8
Q

what do class IV anti-arrhythmics do?

A

Ca2+ channel block

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9
Q

Quinidine is a class ___, ___ block

A

class IA
Na+ block
**also blocks M and alpha receptors

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10
Q

Quinidine indications

A

supraventricular and ventricular arrhythmias
Tx re-entrant arrhytmia (atrial fibrillation)
in dogs and horses

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11
Q

Quinidine binds to Na+ ___ channel to slow AP

A

active Na+ channels

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12
Q

what are the adverse effects of Quinidine based on each receptor it affects (alpha, M)?

A

alpha - hypotension, reflex tachy
M - increases HR, increase AV conduction

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13
Q

Quinidine adverse effects on dog vs horse

A

dogs - anorexia, V, negative inotropism
horse - colic, ataxia, nasal swell

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14
Q

Quinidine contraindications

A

myasthenia gravis
AV block
digitalis toxicity or on digotoxin

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15
Q

Procainamide is a class ___, ___ block

A

class IA
active Na+ block

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16
Q

Procainamide indications

A

ventricular arrhythmia
*NOT very effective in horse

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17
Q

Procainamide metabolite has class ___ activity before excretion

A

class III

18
Q

which drug does more vagal (M and alpha) blocks, Procainamide or Quinidine?

A

QUINIDINE

19
Q

Lidocaine is a class ___ , ____ block

A

class IB
INACTIVE Na+ block

20
Q

Lidocaine indications

A

local anesthetic
Tx ventricular arrhythmia (NOT supra)

21
Q

why does Lidocaine decrease AP duration and shorten ERP?

A

due to block of slow Na+ window currents

22
Q

does Lidocaine decrease contractility?

A

NO

23
Q

Lidocaine adverse effects

A

CNS signs in dogs - drowsy, muscle twitch, convulsions
hypotension
cardiac suppression and CNA excitation in cats

24
Q

Propanolol is a class ___, ___ block

A

class II
Beta block

25
Q

Propanolol indications

A

supraventricular tachycardia
atrial fibrillation
hypertension
ventricular tachy (horses, if not lidocaine)

26
Q

Propanolol contraindication

A

concurrent RAO in horses

27
Q

Atenolol is a class ___, ___ block

A

class II
Beta block

28
Q

Atenolol indications

A

supraventricular tachyarrhythmias
hypertension
hypertrophic CM in ferrets

29
Q

Atenolol is ___ acting than Propanolol

A

longer

30
Q

Esmolol is a class ___, ___ block

A

class II
Beta block

31
Q

Esmolol indications

A

ACUTE management of supraventricular tachy
decreases HR in dogs with ventricular tachy
**use this to test if long acting beta block would work better

32
Q

Esmolol is ___ acting

A

VERY SHORT

33
Q

Sotalol and Amiodarone are class ___, ___ blockers

A

class III
K+ block

34
Q

Sotalol indication

A

arrhythmiogenic CM in boxers

35
Q

Sotalol and Amiodarone effect on cardiac AP

A

prolongs AP and refractory period
decreased efficacy

36
Q

Sotalol contraindication

A

asthma
since a beta block

37
Q

Diltiazem is a class ___, ___ block

A

class IV
Ca2+ block aka CCB

38
Q

Diltiazem indications

A

atrial fib
supraventricular tachy
hypertrophic CM
hypertension

39
Q

Diltiazem blocks ___ channels

A

Ca2+ L type

40
Q

Diltiazem effect on HR, AV conduction, periphery

A

decrease HR
decrease AV
dilate periphery

41
Q

Diltiazem adverse effects

A

vasodilation, NO reflex tachycardia (since blocks AV)
bradycardia
GI/CNS issues
increase liver enzymes
negative inotropic effect

42
Q

Diltiazem causes ___ bioavailability of Propanolol

A

increased