Antiarrhythmics Flashcards Preview

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Flashcards in Antiarrhythmics Deck (66)
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1
Q

which class of drugs decreases cardiac automaticity?

A

B-blockers

2
Q

which class of drugs decreases AV conduction?

A

Ca channel blockers

3
Q

natural pacemaker in the heart

A

SA node

4
Q

Fast AP occurs in … and …

A

purkinje fibers and muscle fibers

5
Q

the … is determined by the steepness of phase 0

A

conduction velocity (Vmax)

6
Q

phase 2 also constitutes the … during which another impulse cannot be generated

A

effective refractory period

7
Q

the steeper the slope of phase 4, the higher the rate of …

A

automaticity

8
Q

… is the time that the cell is depolarized

A

action potential duration

9
Q

… protects heart against arrhythmias

A

effective refractory period

10
Q

slow AP occurs in … and …

A

SA and AV nodes

11
Q

increased/decreased SA node firing

A

altered automaticity

12
Q

abnormal generation of impulses; spontaneous depolarization in another portion of heart leading to generation of AP

A

ectopic pacemaker

13
Q

a unidirectional conduction block

A

reentrant arrhythmia

14
Q

Class IA: Na channel blockers

A

disopryamide, quinidine, procainamide

15
Q

Class IA blockers are most effective with …

A

atrial arrhythmias

16
Q

IA blockers are myocardial depressants that reduce … and … and increase …

A

reduce automaticity and responsiveness (Vmax) and increase ERP

17
Q

most important Class IA Na channel blocker

A

disopryamide

18
Q

Class IA Na channel blockers block … and inhibit rabid inward Na current

A

rapid Na channels

19
Q

Class IA Na channel blockers slow … thereby abolishing ectopic foci

A

phase 4 depolarization (decreases automaticity)

20
Q

Class IA Na channel blockers depress … in slow and fact action potentials

A

the rate of phase 0 depolarization

21
Q

side effects of which drug?: anticholinergic action (urinary retention, dryness of mouth, constipation); generalized cardiac depression; reduction in myocardial contractility

A

disopyramide

22
Q

which class IA Na channel blocker?: IV administration only

A

procainamide

23
Q

Class IB Na channel blockers

A

lidocaine and mexiletine

24
Q

Class IB Na channel blocker used for ventricular arrhythmias in ICUs that arise from myocardial infarctions or digitalis toxicity

A

lidocaine

25
Q

lidocaine is effective only on … and is not effective in the treatment of atrial arrhythmias

A

ventricular arrhythmias

26
Q

Lidocaine will suppress ventricular ectopic foci and will decrease … by decreasing slope of phase 4

A

automaticity of purkinje fibers

27
Q

lidocaine shortens duration of … and …

A

AP and ERP

28
Q

Class IC Na channel blockers

A

flecainide and propafenone

29
Q

Class IC Na channel blockers used for ventricular arrhythmias

A

propafenone

30
Q

Class II B1 Blockers

A

metoprolol, acebutolol, esmolol, propranolol

31
Q

B-blockers are utilized to treat:

A

arrhythmias (heart rate)

32
Q

B1 blockers are used primarily with …

A

atrial arrhythmias

33
Q

Bl blockers reduce … by slowing the transmission of impulses through the AV node

A

ventricular rate

34
Q

B blockers will decrease … of discharge and the conduction velocity

A

the SA node rate

35
Q

primary effect of B blockers is to decrease rate of conduction through … (increases ERP)

A

the AV node

36
Q

B-blockers and … slow conduction through AV node

A

verapamil

37
Q

Class III K channel blockers

A

amiodarone, sotalol, dofetilide, ibutilide

38
Q

K channel blockers prolong the AP and ERP of …

A

purkinje and muscle fibers

39
Q

what has replaced lidocaine as drug of choice in cardiac resuscitation?

A

IV amiodarone

40
Q

Unlike amiodarone and sotolol, … and … are “pure” class III with no Class I, II or IV activity

A

ibutilide and dofetilide

41
Q

Class IV Ca channel blockers

A

verapamil and diltiazem

42
Q

Ca channel blockers used to treat …

A

atrial arrhythmias

43
Q

verapamil is used to reduce ventricular response to atrial flutter or fibrillation by slowing … through AV node

A

conduction

44
Q

Verapamil will depress …

A

Ca dependent action potentials

45
Q

the key effect of verapamil is to … conduction velocity through the AV node

A

depress

46
Q

Verapamil will also slow … of SA and AV nodes

A

slow pacemaker activity (automaticity)

47
Q

both verapamil and diltiazem reduce

A

HR, SA node automaticity, AV conduction, myocardial contractility

48
Q

side effects of which class?: severe bradycardia stemming from AV block, depressive effect on myocardial contractility, contraindicated in patients with sick sinus syndrome, AV block and CHF

A

Class IV Ca channel blockers

49
Q

verapamil and … together may cause AV block

A

Bl Blockers

50
Q

verapamil can increase blood levels of …

A

digoxin

51
Q

Adenosine is a

A

Ca blocker

52
Q

elimination half life of amiodarone is …

A

25 to 100 days

53
Q

digoxin useful for atrial …, … or … because it slows conduction through AV node

A

tachycardia, flutter or fibrillation

54
Q

MoA: digoxin inhibits … and increases intracellular Ca concentration

A

Na/K ATPase

55
Q

Digitalis increases …

A

cardiac contractility

56
Q

direct effects of digoxin on AV node: will have increased … and decreased conduction velocity

A

ERP

57
Q

indirect effects of digoxin: will increase … to the heart and slow HR by increasing baroreceptor firing

A

the vagal activity

58
Q

MoA of digoxin is increased … for muscle contraction and enhanced contractility

A

intracellular Ca availability

59
Q

the other clinical use of digoxin is to reduce …

A

atrial arrhythmias

60
Q

side effect of digoxin increased automaticity of purkinje fibers and elevated risk of …

A

ventricular arrhythmias

61
Q

T1/2 of digoxin is …

A

1.5 days

62
Q

cardiac side effects of digoxin: abnormalities in the cardiac rhythm including …, slowing of the heart rate and …

A

AV block

Ventricular arrhythmias

63
Q

hypercalcemia will … digoxin effects

A

enhance

64
Q

old age will … digoxin clearance

A

decrease

65
Q

hypokalemia … sensitivity to digoxin

A

increases

66
Q

myocardial infarction- digoxin should …

A

not be used