antidysrhythmics

Question 1

what is a dysrhythmia

Answer 1

any deviation from the normal rate/rhythm of the heart

Question 2

what is arrhythmia

Answer 2

no rhythm of heart

Question 3

what is asystole

Answer 3

no heartbeat

Question 4

tachydysrhythmias

Answer 4

HR increased
- much more common

Question 5

bradydysrhythmias

Answer 5

HR slowed
- atropine is drug used (anticholinergic)

Question 6

causes of dysrhythmias

Answer 6

• ischemic heart disease
• myocardial infarction
• cardiomyopathy
• myocarditis
• electrolyte imbalances

Question 7

antidysrhythmics

Answer 7

drugs used for the treatment and prevention of disturbances in cardiac rate and/or rhythm
- most suppress abnormal electrical impulse formation or conduction

Question 8

cardiac electrical activity

Answer 8

SA noce, AV node, purkinje cells, ventricular cells
- movement of ions across the cardiac cell leads to AP generation
- AP leads to contraction of the myocardial muscle

Question 9

how does AP start in the SA and AV node

Answer 9

• Ca influx through calcium channels

Question 11

how does AP start in ventricular and atrial cardiac muscle cells

Answer 11

AP starts with Na influx (depolarization)

Question 12

how does AP end

Answer 12

AP ends with K efflux (repolarization)

Question 13

dysrhythmia symptoms

Answer 13

• palpitations, dizziness, fainting, dyspnea
• some are asymptomatic

Question 14

what are supraventricular tachycardias

Answer 14

problem originates in the atria and makes the ventricles beat faster
(120-125bpm)

• want to create AV block to regulate ventricles

Question 15

types of supraventricular tachycardias

Answer 15

paroxysmal: episodic, start suddenly, return to normal within 24 hrs

persistent: episodes longer than 7 days, treatment needed

permanent: lasts more than a year despite medication

Question 15

atrial flutter (SVT)

Answer 15

atria beats fast in a coordinated fashion, not all atrial beats cause a ventricular beat

Question 16

atrial fibrillation (SVT)

Answer 16

most common
- uncoordinated contraction of atria, originating from all over not just SA node, makes ventricle irregular too

Question 17

ventricular tachycardia (VT)

Answer 17

problem with ventricular muscle
- ventricular dysrhythmias are more dangerous than supraventricular

Question 18

ventricular fibrillation

Answer 18

contractions in uncoordinated fashion, originating from all over the ventricle, quivering, no blood being pumped out

Question 19

antidysrhythmic drug classification

Answer 19

vaughan williams classification
- categorized according to how drugs alter heart function

Question 20

class 1 antidysrhythmic drugs

Answer 20

Na channel blockers

Question 21

class 2 antidysrhythmic drugs

Answer 21

b blockers

Question 22

class 3 antidysrhythmic drugs

Answer 22

K channel blockers

Question 23

class 4 antidysrhythmic drugs

Answer 23

calcium channel blockers

Question 24

other antidysrhythmic drugs

Answer 24

adenosine, digoxin

Question 25

Na channel blockers

Answer 25

physically block Na channels
- slow depolarization
- 1a: quinidine (acute a fib)
- 1b: lidocaine (ventricular dysrhythmias - IV)

Question 26

b blockers

Answer 26

for supraventricular dysrhythmias
- help ventricle beat regularly
- stop Ca from entering cells
- works at the AV node (AV block)
- metoprolol

Question 27

potassium channel blockers

Answer 27

prolong AP and inhibit the next one because the first one cannot end (hold repolarization)
- amiodarone (serious adverse effects, not firstline treatment)

Question 28

calcium channel blockers

Answer 28

stop calcium from entering SA and AV node
- cause AV block
- less electrical activity spread to ventricule
- could still have atrial dysrhythmias
- diltiazem and verapamil

Question 29

digoxin

Answer 29

• AV block
• slows HR

Question 30

adenosine

Answer 30

• AV block
• used for SVT
• IV push
• may cause asystole for a few seconds
• very short half life (10-20 sec)

Question 31

antidysrhythmic adverse effects

Answer 31

all antidysrhythmics can cause dysrhythmias