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anti- arr
block 2 951
63
Science
Professional
10/14/2011

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Cards

Term
state dependent blockade concept
Definition
antiarrhythmics have a higher affinity for channels in the activated or inactivated state because these are the channels most likely to be excessively stimulated (causing the problem).  The channels at rest are not the problem.
Term
What is the common property of the Class I drugs?
Definition

to slow conduction in myocardial tissues in which conduction velocity is controlled by sodium channels

 

(so, myocytes)

Term
t/f: class IA are less effective and less well tolerated than drugs like amiodarone for prevention of AF
Definition
true
Term
Class IA are CI in what condition?
Definition
left ventricular hypertrophy
Term

Which NA channel blockers are 2/3rd line therapy for long term treatment of atrial arrythmias? 

 

(they are considered safe in patients with implantable defibrillator)

Definition

Class IA

 

quinidine, procainamide, disopyramid

Term
What is the first line treatment for Wolff Parkinson White syndrome?
Definition

Procainamide

 

Class IA

Term
Where are Class IB's greatest effects?
Definition
depolarized tissue where it depresses conduction
Term
Where does lidocaine (IB) soar?
Definition
arrhythmias associated with MI
Term

How do flecainide and propafenone work?

 

what are they used for?

Definition

most potent na channel blockers of class I

 

prolong the ap potential at faster rates??

 

suppress PVCs

Term
What are flecainide and propafenone CI in?
Definition

MI

 

heart failure

Term
Flecainide and propafenone cause greater prolong of action potential duration at faster rates.  Why does this matter?
Definition
Contributes to the efficiacy for a fib
Term
Which Class I drug is effective for suppressing PVCs?
Definition

Flecainide

class IC

Term

What drugs are most effective in controlling arrhymias in patients:

 

1. surviving MI

2. Advanced heart failure with reducted ventrcular function

3. adjunctive therapy for implantable defibrilators

Definition
Beta blockers!
Term
What are the three uses of beta blockers?
Definition

1. stop re-entrant arry in AV node

2. controle ventricular response rate in afib/aflutter

2. torsades with emotional stress

Term
Which class is better for suppressing ventribular ectopic depolarizations?  I or II?
Definition
class I
Term

I am a selective beta 1 antagonist availiable for IV use only

 

half life less than 10 minutes

no ISA

 

I am useful in the rapid control of ventricular rate in patient with atrial flutter or fibrillation

Definition
esmolol
Term
Class III drug?
Definition

Amiodarone

 

analog of thyroid hormone

Term
What is amiodarone's MOA?
Definition

1. block sodium channels (phase 0 = decrease slope)

1. k channel block (phase III)

Term
When do you use Amiodarone?
Definition

ventricular arrhythmias

(v. tach, v fib)

 

off label: maintianing sinus rhythm in paroxysmal a fib

Term

Which is more pro-arrhythmic?

 

Class III (amiodarone) or Class I?

Definition
Class I
Term
What cause the decreased TPR (afterload) following IV administration of amiodarone?
Definition

amiodarone's alpha and beta adrenergic antagonist effects

 

may be responsible for its antianginal effects

Term

Name the drug that causes these ADRs:

1. optic neuropathy

2. liver dysfuntion

3. thyroid dysfuntion

4. neuromuscular

5. photosensitivy

6. pulmonary fibrosis

Definition
amiodarone (class III)
Term
What are the three main PK precautions we put on our study guide for amiodarone?
Definition

cyp 3a4 substrate

watch out for QT prolongation drugs

may increase risk of AV block with CCbs, Bblocker and Dig

Term
What drug is comparable to amiodarone but is safer?
Definition

dronedarone (due to iodine removal...but this causes more thyroid adverse effects)

 

it is less lipophilic and it's half life is only 15 hours as compared to ami

Term
Sotalol is the weirdo of the class III.  What other class could it fit into?
Definition

Class II - beta blocker (low doses)

class III (high doses)

Term
should you take sotalol with food?
Definition
negative, ghost writer
Term
t/f: kidney function matters with sotalol
Definition

true

 

very important!!!!

because it is eliminated unchanged!

Term
If sotalol accumulated due to kidney issues what would be the possible outcome?
Definition
torsades
Term
CIs for sotalol
Definition

1. asthma

2. heartblock

3. qt prolongation

4. uncompensated chf

5. CrCl < 40

Term

sotalol must be initated in a setting with continuous ecg monitoring

 

 

Definition
if QT>450 msec at baseline do not use
Term
When should you recheck your patient's QT after administering sotalol?
Definition
2-4 hours after dose
Term
Sotalol's DI list:
Definition

1. other QT prolongers

2. CCBs

3. Beta blockers

4. Antacids

5. bile acid sequestrants

6. calcium

Term

Which drug rapidly converts patients with a fib or atrial flutter of recent onset (<90 days) to normal sinus rhythm?

 

What class does this drug belong to?

Definition

Ibutilide (Covert)

 

III

Term
Which is worse, flutter or fibrillation?
Definition

fib is worse because it is unorganized

 

ibutilide is more successful on atrial flutter (50%) than a fib (30%)

Term
Ibutilide does what to the AP duration and acts on what channel (unique to class III)?
Definition

prolongs AP duration

 

increases sodium (slow) in, so the plateau phase is increase

Term
adverse effects of ibutilide?
Definition

torsades

av block

sustain ventr. tachy

Term
What drugs do ibutilide interact with?
Definition

class I (increases v tach or torsades)

 

QT prolongers (phenothiazine, TCA, FQ)

Term

What is the last class III drug?

ha (this is really strategic for  memorizing purposes)

 

 

What is it used for?

Definition

dofetilide

 

to restore normal sinus rhythm in patients with a fib or flutter

 

to maintain NSR following conversion by other means

Term
Dofetilide is CI for:
Definition

torsades

QT syndrome

QT interval > 450

renal impariment

HR < 50 bpm, bradycardia

 

Term
t/f: dofetilide needs ECG monitoring
Definition
true
Term
t/f: dofetilide should be dosed based on renal function.
Definition
true
Term
Which CCBs are not used as antiarrh?
Definition

dihydropyradines

 

nifedipine

Term
What are the three drugs in the Class IV, that we are concerned with?
Definition

verapamil

diltazem

bepridil

Term
MOA of CCB in antiarr
Definition

l type channel blocker

decrease calcium current

decrease recovery (meaning increase refractory period)

increased frequency, then increased action

decreases conduction velocity thru AV node

Term
clinical use of CCbs
Definition

contorl ventricular response rate in a fib or aflutter

 

diltiazem is oftern the DOC for this indication

 

also, reentrant supraventircular tachy involving the AV node

Term
What class does adenosine belong to?
Definition

TRICK question

 

it's misc

 

(nucleoside)

Term

What should you use to rapidly convert PSVT?

 

(paroxysmal supraventricular tachycardia)

Definition
adenosine
Term
How does adenosine work?
Definition
It increases the refractory period by increasin outward K in phase 3.  Then it inhibits Cacium (because it decreases Camp), which decreases the slope in phase 0 and 4. 
Term
What does theophylline and caffeine do to the dose of adenosine?
Definition
you must increase the dose
Term
dypyrimadole
Definition

promotes clearance of adenosine...decrease the dose

 

 

Term
mg sulfate
Definition

dig induced arry, torsades, acute MI

 

slows rapid signals from SA node

Term
digoxin is used for what?
Definition
control ventricular rate during chronic afib
Term
What wave represents the depolarization of the atria?
Definition
p wave
Term
When does the signal get to the AV node?
Definition
the PR segment
Term
What does the QRS represent?
Definition
depolarization of the ventricles
Term
t/f: all four classes decrease automaticity?
Definition
true
Term
What effect on the ECG oes class IC have?
Definition
Increases QRS (depolarization)
Term
What effect do beta blockers have on the ECG?
Definition

increase PR

decrease HR

Term

What shows up on ECG with class III?

(ami and dofeilide)

Definition
increased QT
Term

What ECG changes occur with CCBs in nodal tissue?

non nodal?

Definition

nodal = increased PR (decreased HR)

 

non nodal = decreased QT

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