antiarrhythmics

Question 1

3 reason a person may get an arrhythmia?

Answer 1

1. disease
2. cardiac injury
3. drugs

Question 2

Cardiac arrhythmias result from

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

Answer 2

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

Question 3

name 8 types of arrhythmias

Answer 3

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

Question 4

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

Answer 4

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

Question 5

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

Answer 5

Complete

Question 6

generally, why are antiarrhythmias used?

Answer 6

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

Question 7

What are the 3 pharmacologic effects of antiarrhythmias?

Answer 7

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

Question 8

What are 4 NON- pharmacologic effects for arrhythmias?

Answer 8

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

Question 9

what are 4 contraindications to giving an antiarrhythmia?

Answer 9

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

Question 10

5 indications that a person needs an antiarrhythmia

Answer 10

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

Question 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?

Answer 11

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

Question 12

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

Answer 12

Phases 0, 1, 2, and most of 3

Question 13

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

Answer 13

Relative refractory period

Question 14

What happens in the absolute refractory period?

synonymous with depolarization

Answer 14

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

Question 15

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

Answer 15

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

Question 16

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

Answer 16

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

Question 17

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

Answer 17

Non refractory phase

Question 18

What drives automaticity?

Answer 18

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

Question 19

What 3 areas of the heart have pacemaker activity?

Answer 19

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

Question 20

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

Answer 20

Informs neighboring cells that something is happening

Question 21

Why are threshold and resting membrane potentials important?

Answer 21

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

Question 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 ______.

Answer 22

pacemaker
longer
repolarize
firing
depolarize
lengthened or shortened

Question 23

when do you want to induce an arrhythmia?

Answer 23

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

Question 24

What are 3 drugs that can induce an arrhythmia?

Answer 24

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

Question 25

rate of contraction

Answer 25

chronotropic

Question 26

force of contraction

Answer 26

inotropic

Question 27

6 toxic reactions to antiarrhythmics

Answer 27

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

Question 28

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

Answer 28

Vagal anticholinergics tachycardia

Question 29

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

Answer 29

potassium | hypokalemia