Antiarrhythmics Flashcards
1
Q
Class IA MOA, Effect, and Uses
A
- MOA:
- Na+ and slight K+ channel blockade
- EFFECT:
- slows phase 0 depolarization
- prolongs repolarization/refractory period
- elevates resting membrane potential
- USES:
- Reentry
- ectopic supraventricular and ventricular tachycardias
2
Q
Quinidine
A
- Class IA
- anticholinergic effects speed up AV conduction
- need to be combined with neg. inotrope
- alpha blockade causes hypotension
- used for: PACs, PVCs, AF/AF to NSR, Preventing SVT, WPW with atrial fibrillation
3
Q
Quinidine adverse effects
A
- GI
- Dig toxicity
- Prolongs QT interval, which may cause Torsades
4
Q
Procainamide
A
- Class IA
- DOC for WPW with Afib
- also used for: SVT (Afib, reentry)
- kidneys convert 50% of dose to NAPA
- Stop treatment until: rhythm suppressed, QT prolonged >50%, or you’ve reached maximum dose
5
Q
Procainamide adverse effects
A
- lupus like syndrome
- agrunulocytosis
- fever
- QT prolongation
6
Q
Class IB MOA, Effects, Uses
A
- MOA:
- Rapidly blocks and un-blocks Na+ channels (best when cells fire rapidly)
- EFFECT:
- shorten phase 3 repolarizaiton
- decrease AP duration
- Use:
- venricular arrhythmias
7
Q
Lidocaine
A
- Class IB
- used to be DOC for ventricular arrhythmias
8
Q
Lidocaine adverse effects
A
- mental status change
- arrhythmias (sinus arrest, AV block, asystole)
9
Q
Class IC MOA, Effects, Uses
A
- MOA:
- potently blocks Na+ channels
- EFFECTS:
- markedly slows phase 0
- significantly prolongs AV refractory period
- USE:
- prevents supraventricular arrhythmias in structurally normal hearts
10
Q
Flecainide
A
- Class IC
- used for SVT (Afib and paroxysmal SVT)
- only use in structurally normal hearts!!
11
Q
Flecainide adverse effects
A
- aggravation of ventricular arrhythmias
- heart failure
- altered mental status
12
Q
Class II MOA, Effects, Uses
A
- MOA:
- beta blockers
- EFFECTS:
- depresses automaticity
- prolongs AV conduction
- decreases heart rate and contractility
- USES:
- SVT
- Vtach
- thyrotoxicosis
- pheochromocytoma
- palpitation prophylaxis
- Vtach after MI prophylaxis
13
Q
Caution using Class II with…?
A
- diabetes (masks signs of hypoglycemia)
- PVD (can cause vasospasm)
- Impotence (exaggerates)
- Asthma/COPD (bronchospasms)
- SSS (further depresses heart rate)
- AV blocks (can make block worse)
14
Q
Class III MOA, Effects, Uses
A
- MOA:
- blocks K+ channels
- EFFECTS:
- prolongs phase 3, prolonging AP
15
Q
Amiodarone
A
- Class III
- Also has Na+, Ca++, and Beta blockade
- Decreases conduction velocity, reentry, rate of fire, automaticity, and inotropy
- DOC for ventricular arrhythmias during resuscitation
- also used for supraventricular arrhythmias and reentrant tachycardia
- low dose for Afib/Aflutter suppression
- Long half-life!!!
16
Q
Amiodarone toxicities
A
-pulmonary, hepatic, thyroid, cardiac, GI, and neuro toxicities
17
Q
Ibutilide
A
- Class III
- affects the slow influx of Ca++ during phase 2, rather than K+ channels
- prolongs AP and increases atrial and ventricular refractoriness
- used for IV chemical cardioversion of Afib
18
Q
Ibutilide toxicites
A
- can cause Torsades de Pointes, so you must check electrolytes (K and Mg) before drug administration
- short half-life
19
Q
Sotalol
A
-Class III
-Also has nonselective Beta-blockade
prolongs AP, increases atrial/ventricular refractoriness, and inhibits conduction in accessory pathways
-Used for SVT and ventricular arrhythmias
20
Q
Sotalol adverse effects
A
-prolongs action potential which can cause development of Torsades
21
Q
Class IV MOA, Effects, Uses
A
- MOA:
- Ca++ channel blockade
- EFFECTS in nodal tissue:
- elevates threshold potential
- slows phase 0 depolarization
- decreases conduction velocity
- lengthens refractory period
- decreases HR
- terminates reentry rhythms through AV node
- Uses:
- AVNRT
- Afib/Aflutter
- MAT
22
Q
Class IV side effects
A
- AVN delays
- bradycardia
- constipation
23
Q
Verapamil
A
Class IV Calcium Channel blocker
24
Q
Diltiazem
A
Class IV calcium channel blocker
25
Do not use Class IV in...?
- wide complex tachycardias of unknown origin
- Afib with WPW
- SSS
- AV blocks without a pacemaker
26
Adenosine
- MOA: K+ channel agonist
- EFFECT: rapid efflux of K+ hyperpolarizes the cells of the SA and AV nodes
- Net effect: slows SA firing and AV node conduction
- DOC for reentrant tachycardias
- DOC for SVT
- must slam and chase due to half-life of only 10 seconds!
- caffeine and theophylline are competitive antagonists - need to use higher dose
27
Adenosine toxicities
- facial flushing
- atrial arrhythmias
- nausea
- shortness of breath
- chest tightness
- caution with asthma and COPD because of bronchospasms
28
Digoxin
- blocks the Na+/K+ pump, increasing intracellular Na+
- Na+ competes with Ca++ for eflux from cell, so intracellular Ca++ is increased
- Used when there's a slow ventricular response with Afib, Aflutter, and Atach
- 3rd choice for SVT
29
Digoxin toxicities
- can make a ladle ST segment depression
- arrhythmias
- GI
- ENT
- do not use with renal failure, hypokalemia, or Afib with WPW
30
DOC for Wolff-Parkinson-White syndrome
Procainamide
31
Old DOC for ventricular arrhythmias
Lidocaine
32
Current DOC for ventricular arrhythmias
Amiodarone
33
2nd DOC for SVT
Verapamil
34
DOC for SVT
Adenosine
35
DOC for reentrant tachycardias (although there are several ways to treat)
Adenosine
36
3rd DOC for SVT
Digoxin
37
Usually the 1st line drug for Afib/Aflutter ventricular rate control
Diltiazem
