In FAST response fibers - Electrolyte involved in phase 0 correct answersNa+ influx
In FAST response fibers - Electrolyte involved in phase 2 correct answersCa+ influx, K+ outflux plateau
In FAST response fibers - Electrolyte involved in phase 3 correct answersK+ outflux (Ca+ drops off) rapid
repolarization
In SLOW response fibers - Electrolyte involved in phase 0 correct answersCa+(few Na+ channels in Nodal
fibers)
In SLOW response fibers - Electrolyte involved in phase 3 correct answersK+ outflux repolarization
In SLOW response fibers - Electrolyte involved in phase 4 correct answers"Mainly Na+ (This is the
pacemaker current) aarapim. "
Ectopic rhythm can result from correct answersischemia, electrolyte abnormalities, or heightened
sympathetic tone
If an early afterdepolarization is sustained correct answerstorades de pointes (QRS complexes of varying
amplitudes)
ECG of a patient with an accessory pathway (bundle of Kent) correct answers"Wide QRS complexes, early
ventricular upstroke (also predisposed to re-entry loops) (Wolff Parkinson White (WPW) syndrome)
wolff-parkinson-white-accessory-bundle-bundle-of-Kent "
MOA of quinidine correct answersBlocks (open-activated) Na+ channels: In SA Nodal tissue - Shift to a
more positive threshold and decrease the pacemaker slope (phase 4), In Ventricular tissue - Decreases
the phase 0 slope (depolarization) and block K+ channels prolongs repolarization (longer refractory
,period protected from reentry currents): Anticholanergic (vagolytic effect faster conduction through AV
node)
Indications of quinidine correct answers"atrial flutter or fibrillation maintain normal sinus
rhythm,Paroxysmal supraventricular tachycardia, Premature atrial or ventricular contractions,
paroxysmal AV junctional rhythm 9"
When taking this drug patients must be monitored for lupus (with ANA) correct answersProcainamide
Take with quinidine to prevent rapid ventricular response in patient with atrial flutter correct answersβ-
blocker or Ca2+ channel blocker
Which 1A antiarrhythmic for a patient on digoxin correct answersProcainamide (doesn't alter digoxin
levels)
MOA of Lidocaine and Phenytoin correct answers( 1B) block of voltage-gated Na+ in ventricular
myocytes (decrease phase 0 upstroke)
MOA of Encainide, Flecainide, Moricizine, Propafenone correct answers( 1C) block of voltage-gated Na+
channelsin ventricular myocytes
MOA of Propranolol, Atenolol, Metoprolol... correct answers( ) block β1-adrenergic receptors SLOW SA
and AV nodal activity,(decreases phase 4 slope)
MOA of Ibutilide, Dofetilide, Sotalol, Amiodarone correct answers( I) Block K+ channels longer action
potential plateau and prolonged repolarization
MOA of Verapamil, Diltiazem correct answers( IV) Ca2+ channel blocker slows action potential upstroke
in SA and AV nodes
This 1A drug is associated with the development of Lupus, hematotoxicity, but less likely to cause
torsades correct answersprocainamide
,Antiarrhythmics of choice for post ischemic insults correct answers1B
Drug used for Supraventricular tachycardias, and post-MI prophylaxis correct answersantiarrhythmics (β-
blockers)
What does Quinidine do to AV node correct answersincreases conduction velocity (via anticholinergic
effects)
This 1A drug is meolized to a meolite with a pure I effect (prolonging refractory, lengthening QT interval)
correct answersProcainamide
DOC or ventricular arrhythmias in ER situations (like in MI) correct answersLidocaine
LidocaineMexiletine should be (increased or decreased) in patients with drug inducible P0 correct
answersincreased
Moderate Na+ channel block decrease phase 0, and prolonged repolarization ( 1A, 1B or 1C) correct
answers1A
Marked Na+ channel block severe decreased in phase 0 slope, No change in repolarization ( 1A, 1B or 1C)
correct answers1C
This drug can worsen the arrhythmia in patients with pre-existing ventricular tachyarrythmias and those
with a history of MI correct answersFlecainide (a 1C)
Drug used when other measure fail to help life threatening paroxysmal supraventricular or vventricular
arrhythmias correct answersFlecainide (a 1C)
, MOA of β1-blockers correct answersblock sympathetic input to AV (and SA nodes) decrease the rate of
phase 4 depolarization (pacemaker current), prolong repolarization
Non-selective β1 and β2 blockers that DO NOT prolong repolarization correct answersFirst generation β-
blockers (Propranolol, Nadolol, Timolol) and carvedilol and labetalol
Β-blocker also used for glaucoma correct answersTimolol
This β-blocker can cause liver damage correct answerslabetalol
These β-blockers cause vasodilationvia α1-blockage correct answersCarvedilol and labetalol
Selective β1-blocker with a very short half-life correct answersEsmolol
Used in ER treatment to block β in thyroid storm correct answersesmolol
A selective β1-blocker and selective β2-agonist correct answersceliprolol
MOA of K+ channel blockers correct answersI antiarrhythmics lengthen the plateau (phase 2) and
prolong repolarization
Lengthening the plateau phase does what (in I) correct answersincreases the refractory period (prevents
re-entry), On the bad side: increases likely-hood of afterdepolarizations and torsades de pointes
Drug for conversion of atrial flutter correct answersquinidine, ibutilide, dofetilide
of amiodarone correct answersMainly I, but has effects in all es
Unique MOA of amiodarone correct answersalters lipid membrane where ion channela and receptors
are located
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