Flashcards in Chapter 23: Cardiac Rhythm Deck (46)
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1
MOA of Class IA Anti-arrhythmics
Block Na + channels
Block K+ channels
in ventricular myocytes
--> decreases conduction velocity thru myocardium
2
Class IA have what effect on AP duration, refractory period, and QT interval?
Increases all 3
3
Class IB effect on AP duration?
Decreases AP duration
4
What is Class IC MOA and effect of AP duration?
Marked (most) block of Na+ channels
Does not change AP duration
5
What are Class II drugs?
B-blockers...LOL!
6
MOA of Class III? Effect on AP duration, QT and refractory period?
K+ channel blockers
Increase AP duration
Increase refractory period
Increase QT interval
7
When do you use Class III?
When other anti-arrythmics fail
8
Class IV MOA? What do they do to conduction velocity, refractory period, and PR interval?
Ca2+ channel blockers
decrease conduction velocty
increase refractory
increase PR interval
9
Adenosine MOA?
opens G protein coupled K+ channel and suppress Ca dependent AP
--> increases K OUT of cell....suppress Ca AP
= inhibits SA node, atrial, and AV nodal conduction
10
Name the class IA drugs
quinidine
procainimide
disopyramide
11
Name the class IB drugs
Lidocaine
Mexiletine
Phenytoin
12
Name the class IC drugs
Flecainide
Propafenone
13
Name the class III drugs
Ibutilide
Dofetilide
Sotalol
Bretylium
Amiodarone
Dronedarone
14
Name the class IV drugs
Verapamil
Diltiazem
15
Quinidine toxicity?
cinchonism (impaired hearing, headache, dizziness)
16
Procainamide toxicity?
lupus like syndrome (almost all chronic users get this...think increase ANAs)
17
Disopyramide toxicity?
heart failure
18
All class IAs can cause what serious adverse effect?
Torsades des pointes
19
What should be used in conjunction with quinidine?
An agent that will slow AV nodal conduction
- Ca channel blocker or B blocker
20
What drug may be used in hypertrophic cardiomyopathy because it decreases cardiac contractility?
dispyramide
21
Quinidine induced ____ toxicity may occur in a fraction of patients
digoxin
22
What is the drug used to maintain normal sinus rhythm after conversion of atrial flutter?
procainamide
23
What is the class IA drug for paroxysmal supraventricular tachycardia? What if this fails?
quinidine (class IA)
if fails, try a class IC --> used as last resort drugs
= Flecainide or Propafenone
24
_____ suppresses purkinje automaticity without affecting the SA node
Lidocaine
25
Clinical use of lidocaine/mixiletine?
Ventricular arrythmias in context of MI, cardiac manipulation or cardiac glycosides
26
Class IB has an effect on what type of tissue?
INJURED/DISEASED myocardium
27
What drug is used for local anesthesia of skin or mucous membranes?
lidocaine
28
Clinical use of phenytoin?
tonic-clonic seizures
status epilepticus
non epileptic seizures
29
IB is Best ____
IC is Contraindicated _____
post MI
post MI/structural heart disease
30
What drugs are associated with excessive mortality and nonfatal cardiac arrest? (restrict these drugs to people who have failed other measures)
Class IC
= flecainide
propafenone
31
What type of drug would you give to decrease the likelihood for mortality and re-infarction after MI?
B blockers!
32
Ibutilide clinical use?
conversion of atrial fibrillation/atrial flutter to normal sinus rhythm
33
What must you do if giving ibutilide? Why?
monitor QT interval during administration
Bc 2% develop torsades des pointes and need cardioversion
34
Sotalol clinical use?
life threatening ventricular arrhythmias when patients can't tolerate amiodarone
35
Adverse effects of sotalol? So don't use in pts that have a hx of __?
bradycardia
bronchospasm --> dont use in pts with asthma!!
36
When v. arrythmias don't respond to lidocaine or defibb, what drug should you try?
Bretylium (no effect on atrial tissue)
37
What drugs targets the entire lipid membrane and can thus be considered a multi-class anti-arrhythmic?
amiodarone
38
Co-administration of amiodarone with what drug would decrease amiodarone levels?
phenytoin
39
Amiodarone toxicity?
severe pulmonary toxicity
thyroid dysfunction (40% iodine by weight)
Corneal deposits
Blue-gray skin discoloration
photosensitivity
40
Which of the class III drugs can cause torsades des pointes?
sotalol
ibutilide
41
Drug used for a fibb/a flutter that is similar to amiodarone, but has a shorter half life and less thyroid toxicity?
dronedarone
42
Don't use dronendarone in patients with what?
systolic heart failure!
43
What is the drug of choice for paroxysmal supraventricular tachycardia?
adenosine
44
Is adenosine short or long acting? What are the toxicities?
VERY short acting - 15sec
Facial flushing
Chest pressure
Diaphoresis
45
Do not use adenosine to treat ____
atrial fibb or atrial flutter
46
