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Pharm - Arrhythmias
Exam 3
124
Pharmacology
Graduate
04/11/2010

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Cards

Term
What is the chief complaint when a patient comes in for an arrhythmia?
Definition
palpitations
Term
T/F
Bradycardia presentation is usually different from other arrhythmias.
Definition
true
Term
How do bradycardias present?
Definition
chronic fatigue
dyspnea on exertion
syncope or near syncope
Term
How might you discover an arrhythmia in an asymptomatic patient?
Definition
checking vitals - pulses
auscultation of the heart
routine EKG
Term
What lab tests would you run on a patient with an arrhythmia?
Definition
chem panel - electrolytes and glucose
CBC - anemia
TSH
EKG
Term
When should you absolutely not give amiodarone?
Definition
pregnancy and during lactation
Term
What anti-arrhythmic drugs should not be given during lactation?
Definition
amiodarone and acebutolol
Term
T/F
During pregnancy there is an increase in arrhythmias.
Definition
True
Term
T/F
Pseudophedrine or other sympathomimetic drugs may cause an arrhythmia.
Definition
True
Term
What are the potential cardiac causes of PACs? Other causes?
Definition
cardiac: mitral stenosis, CAD, hypertrophic cardiomyopathy

other: caffeine, theophylline, tobacco, alcohol, COPD, chronic renal
Term
What EKG changes are there to indicate PACs (premature atrial contraction)?
Definition
short or prolonged PR interval
inverted or biphasic p waves
aberrant or absent QRS
Term
How do you treat asymptomatic patients with PACs?
Definition
education, reassurance, possible dietary/med changes if causative agent
Term
How do you treat symptomatic patients with PACs?
Definition
beta blockers - variable results
refer to cardiologist
Term
What medications should not be used to treat symptomatic patients with PACs? Why?
Definition
IA, IC, or III anti-arrhythmic agents
(quinidine, procainamide, flecainide or those that inhibit ventricular repolarization or prolong refractoriness)

high risk for proarrhythmia and QT prolongation
Term
How are anti-arrhythmic drugs classified?
Definition
Vaughn-Williams Classification

classified by effect on ventricular contraction velocity, repolarization/refractoriness, and automaticity
Term
What are Class I anti-arrhythmics?
Definition
Na+ channel blcokers
Term
What are class II anti-arrhythmic agents?
Definition
beta blockers
Term
What are class III anti-arrythmic agents?
Definition
drugs that inhibit ventricular repolarization or prolong refractoriness
Term
What are class IV anti-arrhythmic agents?
Definition
non-dihydropyridine CCBs: verapamil and diltiazem
Term
T/F
Some drugs can have multiple anti-arrhythmic classifications based on it's effects.
Definition
True
Term
What are the classifications of Ia, Ib, and Ic?
Definition
Ia - intermediate, intermediate potency
Ib - fast on/off, lowest potency
Ic - slow on/off, highest potency
Term
What do class I anti-arrhythmic agents do?
Definition
1. lengthen the refractory period
2. decrease excitability
3. decrease conduction
4. block K+ channels - mild
5. lengthen the action potential duration - wider QRS
Term
T/F
The effect of class I anti-arrhythmic drugs is rate dependent.
Definition
True
Term
When is slowed conduction apparent for class Ib drugs?
Definition
only apparent at fast rates
Term
When is slowed conduction apparent for Ic drugs?
Definition
apparent at normal rates
Term
T/F
Normal tissues are affected by class Ib drugs. Ic drugs?
Definition
False
True - Ic drugs affect all tissue
Term
T/F
The effect of class I anti-arrhythmic drugs is pH dependent.
Definition
True - original compounds are bases and become active by adding an H+

acidosis will increase effects
alkalosis will decrease effects
Term
Name 2 Class Ia drugs.
Definition
quinidine and procainamide
Term
What is quinidine syndrome?
Definition
recurrent light-headed-ness, fainting, and drug-induced Torsade de pointes caused by quinidine
Term
What are some problems associated with procainamide?
Definition
arthralgia similar to lupus in 33%
icreased ANA titer
pleuritis
pericarditis
Term
Name 2 class Ib drugs.
Definition
lidocaine and phenytoin
Term
What are 2 potential problems with using lidocaine?
Definition
must be injected properly or it can cause cardiac effects

can cause hypotension by depressing myocardial contractility
Term
Name 1 class Ic drug.
Definition
flecainide
Term
Which drug would you use the lowest dose on and has the longest lasting effect - Ia, Ib, or Ic?
Definition
Ic because it is the highest potency
Term
What EKG changes typify PVCs?
Definition
wide, bizarre QRS
QRS > .12 sec
inverted T wave
compensatory pause following QRS
Term
What % of middle aged people have PVCs on a 2 minute EKG?
Definition
6%
Term
T/F
Post MI, more than 10 PVCs per hour is associated with a worse prognosis.
Definition
True
Term
What % of HF or cardiomyopathy patients have PVCs? Are they of prognostic value?
Definition
70-95%

No prognostic value
Term
T/F
Patients with LVH have an increased incidence of PVCs and it correlates to a higher risk of sudden death.
Definition
True
Term
How do you treat a patient with PVCs who has no heart disease?
Definition
You don't!

anti-arrhythmic therapy increases the risk of death
Term
How do you treat the patient with PVCs and structural heart disease (CAD, cardiomyopathy, CHF)?
Definition
radiofrequency ablation and referral for Class I anti-arrhythmic drugs and perhaps amiodarone
Term
How do you treat the symptomatic patients with PVCs in the outpatient setting?
Definition
First line - class II - beta blockers
- sotalol - class II and III

amiodarone may be used if Beta blockers are counterindicated
Term
Sotalol
Definition
class II and class III anti-arrhythmic drug

Do not use in asymptomatic patients due to proarrhythmia affects

treat with O2 to avoid proarrhythmic affects of beta blockers
Term
Who should not be treated with beta blockers?
Definition
asymptomatic patients with PVCs - possible proarrhythmia effects
Term
Name 4 possible causes of bradycardia.
Definition
1. Sick sinus syndrome
2. exaggerated vagal activity
3. acute MI
4. obstructive sleep apnea
Term
How do you treat the asymptomatic patient with bradycardia?
Definition
You don't!

increase O2, have pt lie supine with raised legs, increase fluids if no JVP distension
Term
How do you treat the symptomatic patient with bradycardia?
Definition
may require pacing
adrenaline
isoprenaline
Term
What is the heart rate in PSVT?
Definition
150-250 bpm
Term
What is the heart rate in atrial flutter?
Definition
250-350 bpm
Term
What is the heart rate in atrial fibrillation?
Definition
350-600
Term
Describe the EKG of PSVT.
Definition
narrow complex tachycardia with a regular rate
Term
What % of cases of PSVT are AV nodal re-entrant? AV re-entrant? atrial tachycardia or sinoatrial tachycardia?
Definition
60%
30%
10%
Term
What disorder is AV re-entrant tachycardia associated with?
Definition
WPW
Term
T/F
PSVT is benign and self-limited.
Definition
True
Term
What are some types of non-pharmacologic treatment fro PSVT?
Definition
vagal maneuvers
avoid: caffeine, alcohol, tobacco, stress, pseudophedrine
ice-cold wet cloth to the face
stimulate gag reflex
bend over and touch floor
exhale followed by deep inspiration with mouth closed and nose pinched
Term
What is the most common symptomatic pediatric arrhythmia?
Definition
PSVT
Term
T/F
PSVT that is sustained with instability requires immediate cardioversion.
Definition
True

instability may be: angina, SOB, decreased level of consciousness, hyptension, or CHF
Term
When is adenosine cardioversion counterindicated?
Definition
wide complex tachycardia and in WPW (delta waves)
Term
What drug is used to cardiovert narrow complex PSVT?
Definition
adenosine
Term
After cardioversion with adenosine, what is used for maintenance?
Definition
amiodarone
Term
What is the mechanism of action of adenosine?
Definition
enhanced K conductance
suppression of calcium dependent action potentials

This inhibits AV nodal conduction and increases the AV nodal refractory period
Term
What are the signs and symptoms of adenosine toxicity?
Definition
flushing - 20%
SOB or chest burning - 10%
headache
hypotension
nausea
Term
How do you treat PSVT in outpatient?
Definition
cautious use of beta-blocker
verapamil
Term
How do you treat PSVT in ED?
Definition
emolol
selective radiofrequency ablation
cardioversion - start at 50J
Term
Describe atrial fibrillation.
Definition
Irregularly irregular
wavy baseline with no P waves
350-600 bpm
Ventricular response 120-180 bpm
Term
What classifies acute atrial fibrillation?
Definition
< 48 hours
Term
What classifies paroxysmal atrial fibrillation?
Definition
terminates spontaneously in 7 days
Term
What classifies persistent atrial fibrillation?
Definition
longer than 1 week
Term
T/F
Permanent atrial fibrillation is not pharmacologically or electrically convertible.
Definition
True
Term
T/F
In atrial fibrillation there are multiple re-entrant pathways.
Definition
True
Term
Describe atrial flutter.
Definition
Saw tooth pattern
Term
What is the drug of choice to treat atrial fibrillation and atrial flutter? Name 2 other drugs that may be used.
Definition
Digoxin

Beta blockers and CCBs - used to control the rate; may not be beneficial; unmask heart failure
Term
T/F
Anticoagulate with atrial fibrillation and atrial flutter.
Definition
True
Term
What do you use to anticoagulate a patient with atrial fib or atrial flutter?
Definition
warfarin sodium
Term
Which clotting factors are destroyed by Protein C?
Definition
Va, VIIIa, and XIa
Term
Which factors are inactivated by heparin?
Definition
VIIa, IXa, Xa,and IIa
Term
How does heparin inactivate clotting factors?
Definition
by activating anti-clotting factors such as antithrombin III which inactivates 7a, 9a, 10a, and 2a
Term
Which clotting factors' synthesis is inhibited by warfarin?
Definition
VII, IX, X, and II
Term
Where does heparin act?
Definition
in the blood
Term
Where does Warfarin sodium act?
Definition
in the liver
Term
How long do the effects of warfarin take to show up? Why does it take so long?
Definition
1-3 days

1. some clotting factors have long half lives, so it takes time for their synthesis inhibition to be seen
2. It takes time to get to the peak drug concentration
Term
What is the bioavailability of Warfarin?
Definition
100%
Term
What is the half-life of coumadin?
Definition
36 hours
Term
What is a warfarin diet? Why might it be followed?
Definition
avoiding green leafy veggies because they are a source of vitamin K

Vitamin K is used to make clotting factors and therefore reduces the efficacy of the warfarin
Term
T/F
Patients on coumadin may need higher dosing in the winter.
Definition
False - they may need higher dosing in the summer
Term
What meds should be avoided while on coumadin therapy?
Definition
NSAIDs and aspirin (reduce to 81 mg daily at least)
Term
What pregnancy category is warfarin?
Definition
X
Term
How do you dose coumadin?
Definition
Increase dose at 1 week intervals based on INR

INR of 2-3 for anticoagulation
INR of 2.5-3.5 for mechanical heart valve patients
INR of 1.5-2.0 to prevent VTE after first six months of therapy
Term
T/F
Drug interactions with warfarin are numerous
Definition
True
Term
What drugs increase the INR of a patient on coumadin?
Definition
amiodarone
antibiotics
antifungals
omeprazole
cimetidine
Term
How do you treat overcoagulation with warfarin?
Definition
injectable vitamin K
Term
Why should you limit OTC remedies with a patient on coumadin therapy?
Definition
herbal interactions also exist
Term
What is the success rate for direct-current cardioversion in a fib and atrial flutter?
Definition
80%
Term
What drug is given 3-4 weeks before attempting cardioversion of a fib and atrial flutter?
Definition
amiodarone
Term
What test should be done before conversion?
Definition
transesophageal ECHO to find atrial thrombi that would require anticoagulation before conversion
Term
What 2 drugs do you use to maintain rhythm after cardioversion?
Definition
warfarin and amiodarone
Term
Which drug is used to pharmacologically convert a fib or a flutter? What is the success rate?
Definition
high dose amiodarone

86% if a fib has existed less than 2 years
Term
What is the action of amiodarone?
Definition
1. slows the sinus rate
2. slows AV conduction - prolongs QT interval and QRS complex
3. increases refractory periods
Term
T/F
Amiodarone is prorhythmic.
Definition
True - it is unlikely that an arrhythmia will develop or worsen while on this med.
Term
What is the mechanism of action of amiodarone?
Definition
1. Fast Na+ channel blocker
2. K+ channel blocker
3. noncompetative alpha and beta blocker
4. weak Ca2+ channel blocker
Term
How is amiodarone classified as an anti-arrhthmic?
Definition
could be classified as Class I, II, III, or IV
Term
What are the 2 effects of amiodarone?
Definition
antianginal and peripheral vascular dilation
Term
T/F
The number and severity of toxic effects increases with the dosage of amiodarone.
Definition
True
Term
Name 3 cardiac side effects of amiodarone.
Definition
bradycardia
heart block
heart failure
Term
What % of patients on amiodarone develop pulmonary fibrosis?
Definition
5-15%
Term
What are some of the extra-cardiac side effects of amiodarone?
Definition
pulmonary fibrosis, skin deposits - photodermatits or blue discoloration, CNS paresthesia, tremor, ataxia, headache, thyroid dysfunction - hyper or hypo, and liver necrosis
Term
What % of patients on amiodarone develop photodermatitis? Smurf discoloration? thyroid dysfunction?
Definition
25%

5%

5%
Term
When do the effects of interaction between amiodarone and concomittant therapy peak?
Definition
7 weeks after initiation
Term
How often should liver and thyroid function tests be done on amiodarone pts?
Definition
at least every 6 months
Term
At which dose of amiodarone is there a low incidence of lung or thyroid effects?
Definition
200 mg or less
Term
What is the half life of amiodarone?
Definition
highly variable and unusually long - averaging about 58 days
Term
When might Torsade de pointes be seen?
Definition
When a pacemaker is past the end of its life and needs to be replaced
Term
What typifies a ventricular tachycardia?
Definition
wide QRS compex - VT until proven otherwise

other: evidence of AV dissociation, independent p waves, capture of fusion beats, beat to beat variability in QRS morphology, QRS complexes > .14 secs
Term
T/F
History of ischemic heart disease makes VT more likely.
Definition
True
Term
How high is the mortality rate for VT after 2 years?
Definition
higher than 30%
Term
What is the best treatment for VT?
Definition
auto cardioverter-defibrillator implantation
Term
How do you treat hemodynamically unstable VT patients?
Definition
electrical cardioversion
Term
How do you treat stable VT patients?
Definition
amiodarone until implant can be put in
Term
T/F
Athletes tend to have low HRs.
Definition
True
Term
How long can an asymptomatic sinus pause be and still be benign in an athlete?
Definition
3 seconds
Term
What is responsible for some cardiac related deaths in athletes?
Definition
idiopathic hypertrophic cardiomyopathy
Term
How do you diagnose idiopathic hypertrophic cardiomyopathy? what is the treatment?
Definition
aortic murmur that increases with Valsalva's maneuver

stop playing sport
Term
Supraventricular tachycardias in children are usually associated with what disorder? How do you treat?
Definition
WPW

adenosine or radiofrequency ablation
Term
What drug might you consider to control the heart rate in children (when there are extra beats)?
Definition
beta blocker (atenolol)
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