antiarrhythmics Flashcards Preview

Pharm II > antiarrhythmics > Flashcards

Flashcards in antiarrhythmics Deck (29):
1

3 reason a person may get an arrhythmia?

1. disease
2. cardiac injury
3. drugs

2

Cardiac arrhythmias result from
1. abnormal impulse _____ - arise from non-traditional ____
2. abnormal impulse _____ - abnormal pathways due to _____
3. _______ of both

1. formation - locations
2. conduction - blockages
3. combination

3

name 8 types of arrhythmias

1. at nodal level
2. at conduction level
3. premature contractions
4. tachycardia
5. flutters
6. fibrillations
7. bradycardia
8. heart block

4

At the conduction level, there are 4 types of arrhythmias, what are they?

1. normal pattern of conduction but conduction splits and goes two ways
2. re entry
3. unidirectional block
4. prolonged refractory period

5

_____ heart block = His/Purkinje system cut in half, atria and ventricles work indpendently

Complete

6

generally, why are antiarrhythmias used?

Used to modify/restore aberrant electrophysiologic properties of cardiac muscle to normal aka depress parts of the heart that are beating abnormally

7

What are the 3 pharmacologic effects of antiarrhythmias?

1. change slope of depolarization
2. raise threshold for depolarization
3. alter conduction velocity in different parts of the heart

8

What are 4 NON- pharmacologic effects for arrhythmias?

1. electrical cardioversion
2. automatic implantable cardioverter devices
3. ablation therapy
4. pacemakes

9

what are 4 contraindications to giving an antiarrhythmia?

1. complete AV heart block
2. CHF
3. hypotension
4. known hypersensitivity to the drug

10

5 indications that a person needs an antiarrhythmia

1. paroxysmal atrial tachycardia
2. paroxysmal ventricular tachycardia
3. atrial fibrillation
4. ventricular ectopic arrhythmias
5. digoxin-induced arrhythmias

11

antiarrhythmic medications work on 1 of 5 trans membrane phases of the cardiac cycle which alter the phases to control rhythm, what are the 5 phases?

Phase 0 - influx of Na ions -> depolarization
Phase 1 - partial repolarization through efflux of K ions
Phase 2 - plateau where net influx of Ca is slightly more than the efflux of K
Phase 3 - efflux of K
Phase 4 - restoration of ionic concentrations via Na/K & Na/Ca exhange pumps

12

What phases of the cardiac cycle are part of the absolute (effective) refractory period? (-50mV)

Phases 0, 1, 2, and most of 3

13

What is the name in the cardiac cycle during the middle of phase 3 to beginning of phase 4?

Relative refractory period

14

What happens in the absolute refractory period?
(synonymous with depolarization)

cells cannot respond to a stimulus, its a mechanism that protects the heart from all other ectopic impulses

15

When is the only time that a strong stimulus can cause depolarization?

Relative refractory period - occurs when repolarization is almost complete (cells may all respond differently)

16

The length of time between refractory periods varies between individuals, what 6 things affect it?

1. medications
2. recreational drugs
3. disease
4. electrolyte imbalance
5. myocardial ischemia
6. myocardial injury

17

In what phase are all the cells repolarized and ready to respond in a normal fashion?

Non refractory phase

18

What drives automaticity?

Spontaneous opening and closing of K channels (the net flow of these ions repolarized the cell, then depolarizes to threshold

19

What 3 areas of the heart have pacemaker activity?

1. SA node (main)
2. AV node
3. Purkinje Fibers

20

Why is the rate of depolarization (Phase 0) important?

Informs neighboring cells that something is happening

21

Why are threshold and resting membrane potentials important?

Determines how easily and how frequently cells can depolarize, the further away from these potentials that the cell is maintained, the harder it will be to get the cell to depolarize

22

.Effective Refractory Period in cells in ____ areas is ___ than in myocardial cells. Myocardial cells _____ quickly and have to wait for the pacemakers to repolarize before ___ again. Ensures that all cells are repolarized before being told to _____ again. Different arrhythmias require that the ERP be _____ or ______.

pacemaker
longer
repolarize
firing
depolarize
lengthened or shortened

23

when do you want to induce an arrhythmia?

For temporary heart block until a pacemaker is inserted and with ventricular arrhythmias due to AV node block

24

What are 3 drugs that can induce an arrhythmia?

1. Epinephrine
2. Isoproterenol - beta 1 and beta 2 agonist
3. hypokalemic diuretics

25

rate of contraction

chronotropic

26

force of contraction

inotropic

27

6 toxic reactions to antiarrhythmics

1. hypersensitivity
2. hypotension
3. shock
4. paradoxical arrhythmias
5. GI disorders
6. Cinchonism

28

The ___ blocking effects of antiarrhythmic drugs and ______ (eg atropine) can act synergistically and lead to _____.

Vagal
anticholinergics
tachycardia

29

Therapeutic effects of antiarrhythmics are increased by ____ (and reduced in _____)

potassium
hypokalemia