Anti-arryhthmics Flashcards
SA and AV node are considered _____ tissue in terms of speed
slow
atria/ventricles/His-Purkinje fibers are considered _____ tissue in terms of speed
fast
Na channel blockers ____ excitability and _____ refractory period
decrease
increase
K channels blockers _____ APD and ____ refractory period
increase
increase
Ca channel blockers ____ excitability and ____ refractory period
decrease
increase
Beta-blockers modulate ____ and ___ channels in slow tissue
K
Ca
____ ____ refers to a time when too few Na channels are in the resting state and an action potential cannot be generated
refractory period
The number of Na channels in the resting state roughly equates to ____
excitability
Ability of a depolarization to cause an AP is ____ (aka threshold)
excitability
slow-dissociating Na channel blockers prolong the _____ complex
QRS
____-dissociating Na channel blockers do not effect the ECG significantly
fast
slowing the rate of phase ____ depolarization is associated with prolongation of the QRS complex
0
Blocking Na channels during phase ____ will reduce excitability while blockage during phase ___ or ____ will increase refractory period
0
3
4
Prototype fast-dissociating Na channel blocker
lidocaine
____ channel blockers prolong the QT interval
K
decrease conduction velocity and excitability along with increase refractory period of slow tissue is attributed to ___ channel blockers
Ca
PR interval is prolonged by ___ channel blockers
Ca
QRS complex is prolonged by ____ channel blockers
Na
QT interval is prolonged by ___ channel blockers
K
Delayed aftedepolarization is associated with which drug
digoxin
____ causes a premature ventricular beat for every normal sinus rhythm beat
digoxin
delayed afterdepolarizations are due to elevated ___
Ca
____ blockers slow conduction in fast tissue and ____ blockers slow conduction in slow tissue
Na
Ca
Which 2 drugs are the only drugs shown to reduce mortality
beta blockers
amiodarone
Order the classes of Na channel blockers fastest to slowest
b
a
c
This class of Na channel blockers widens QRS and prolongs the QT interval
a
class 1A Na channel blocker prototype
quinidine
This drug blocks Na and K channels, alpha-adrenergic blockade, and anticholinergic effects
quinidine
Maintain sinus rhythm in a-fib/flutter and suppress supraventricular and ventricular tachyarrhythmias
quinidine
Prolong QT interval and increased risk of torsades de pointes
quinidine
This drug has an interaction with digoxin and increases the serum levels of digoxin
quinidine
- avoided in long term use
- metabolite blocks K channel but not Na
- lupus-like syndrome especially in slow acetylators
procainamide
Class 1B Na channel blocker prototype
lidocaine
selective for ventricular over atrial blockage of Na channels
lidocaine
- Acute IV therapy for ventricular arrythmias
- not effective against atrial arrythmias
- concern about increased mortality
lidocaine
This class of Na channel blockers has minimal effects on ECG
1B (lidocaine)
Seizures with rapid IV administration of this drug
lidocaine
prototype class 1C Na channel blocker
flecainide
increases mortality in patients recovering from MI
flecainide
Blurred vision
flecainide
- beta adrenergic blockade
2. blood levels are increased in slow CYP2D6 metabolizers
propafenone
used for life-threatening ventricular arrhythmias
flecainide
increases refractory period of AV
metoprolol
decreases mortality after MI
metoprolol
SA and AV node block
metoprolol
sudden withdrawal may worsen symptoms
metoprolol
short-term decrease of ventricular function
metoprolol
____ channel blockers will prolong the APD
K
this drug is the prototype drug that prolongs APD
amiodarone
non-competitive adrenergic receptor blocker
amiodarone
refractory v-tach or v-fib
amiodarone
maintain NSR in a-fib
amiodarone
pulmonary fibrosis and thyroid dysfunction
amiodarone
half-life of 1-2 months
amiodarone
non-selective beta-blocker that also blocks K channels
sotalol
severe atrial flutter or a-fib
sotalol
torsades in overdose & not approved for use as antihypertensive or antianginal
sotalol
pure K channel blocker
dofetilide
restricted to patients with a-fib to maintain NSR
dofetilide (tikosyn)
depresses cardiac force of contraction
verapamil
contraindicated in CHF
verapamil
constipation
verapamil
decreases slow tissue automaticity and excitability
verapamil
used to treat WPW syndrome
adenosine
brief (5 sec) asystole
adenosine
flushing and metallic taste
adenosine
DI with caffeine
adenosine
may invert T wave
digoxin
especially useful in heart failure as other agents used to treat it decrease contractility
digoxin
