Exam 1 - Week 3 - Dysrhythmias Flashcards
When do you choose rate control?
Class 2 & 4
Use AV nodal agents
Asymptomatic
Without CHF
When do you choose rhythm control?
Class 1 & 3
Interfering cellular level, interfering electrical/pharm
symptomatic, with CHF
What is class 1?
Na channel blockers
What is class 1a?
quinidine, procainimide, disopyramide
Older meds, rarely used
What rhythms are class 1a drugs used for?
ventricular arrythmias, recurrent afib, WPW syndrome
What is class 1b?
lidocaine, phenytoin, Mexiletine
What rhythms are class 1b drugs used for?
MI (discouraged now)
Cause asystole, vtach, and afib
Used by specialist only
What is class 1c?
flecainide, propafenone
What is class 1c used for?
Doesn’t affect action potention (no shift)
Prevents paroxysmal afib, tx of recurrent tachy, contraindicated post MI
What labs do you want with class 1c?
LFTs, CBC, ANA, kidney fx, urine pH (affects drug excretion)
What diagnostic test do you want with class 1c?
EKG–look at QRS
Should see 10% increase to know drug is effective
Special considerations for admin of class 1c?
Use with AV nodal agents (BB and CCB)
Without use of AV nodal agent you can contribute to ventricular rhythm which can be fatal
What are class 2 drugs?
Beta-Blockers
How do class 2 drugs work?
Decrease conduction through AV node and block catecholamine response
What do class 2 drugs treat?
SVT (atrial tachy)
Name four class 2 drugs.
Atenolol
Metoprolol (tartrate & succinate)
Nadolol
Propranolol
What do class 2 drugs do?
Control rate and rhythm
Can class 2 drugs be used alone?
Effective as monotherapy
What are class 3 drugs?
K+ channel blockers
What is the MOA of class 3 drugs?
Block K+prolong repolarization
What is different about the class 3 drug sotalol?
It is a beta blocker and does not convert
Name four class 3 drugs
Amiodarone, sotalol, dofetilide, drondedarone
What is significant about class 3 drugs?
Pt needs to stay in hospital to observe for side effects before discharge
What are special considerations for dofetilide?
If you miss a dose, do NOT double, take next dose.
If you miss a dose again, go to the hospital to start over. Compliance is important.
What is significant about drondedarone?
BLACK BOX WARNING–contraindicated in NYHA stages II-IV.
Contributes to HF and death in stage 2 & 3
What is significant about amiodarone?
Best drug for afib.
Can turn patient’s skin blue
What labs do you monitor with amiodarone?
TSH, LFT, BMP (can damage, lungs, liver & thyroid)
What are class 4 drugs?
Calcium Channel Blockers
What is MOA for class 4 drugs
Decrease conduction through AV node -shorten Phase 2-plateau- (shorten Action Potential)
Allow adrenergic control of HRT and contractility
Why is class 4 questionable in HF?
Decreases contractility of heart
What are nondihydropyridines?
Older class, more antianginal properties, minimal effect on BP, negative inotropic effect, constipation
Verapamil and diltiazem
Special considerations for diltiazem?
Not as many AE as BB
Good negative inotropic effect
Can cause constipation in elderly
What drugs are in class 5?
Digoxin, mag sulfate, adenosine
Digoxin
Decreases conduction through AV node
Increases Vagal activity
Action is central-on CNS
Adenosine
Resets heart, 2 doses of 6mg
ED to convert SVT, AVRT, AVNRT
Mag Sulfate
Torsades de pointes
