Antiarrhythmic Drugs

This is a brief overview of antiarrhythmic agents, or drugs used to resolve abnormal cardiac rhythms.
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ADDITIONAL TAGS
Class IA antiarrhythmic agent
Moderate sodium s, which s action potential duration
Quinidine
side effects blocks hERG , which results long QT and can cause torsades de pointes
Procainamide
Less prolongation QT segment, less TdP
Disopyramide
s force contraction heart
Side effects: constipation, urinary retention, glaucoma
IB antiarrhythmic
Mild sodium s, which s action potential duration
Lidocaine
Intravenous only
Mexiletine
Can be administered orally
IC antiarrhythmic
Marked sodium s, doesn’t change action potential duration
Flecainide
Possibly produces an ventricular arrhythmias
Propafenone
Some beta er effects (bradycardia and cardiac inotropy)
addition to changing AP duration by changing Na influx, Is also:
phase 4 depolarization
threshold potential
sub
degree Na+
AP duration change
Beta-adrenergic receptor ers (beta ers)
catecholamines (norepinephrine, epinephrine, dopamine)
Reduces myocardial need for oxygen, can ischemia
slope phase 4 depolarization s self-generated rhythmic firing heart (s automaticity)
Prolong repolarization AV node → reentry
Effectively s refractory period
III antiarrhythmic
s potassium s (delayed-rectifier potassium (DRK) s)
Prolongs repolarization (phase 3)
Amiodarone, Sotalol, Ibutilide, D etilide, Dronedarone
III: Amiodarone
Wide range effects through many mechanisms
s sinus node firing
s automaticity
s reentrant circuits
s Na, K, and Ca s ( I, III, IV antiarrhythmics)
s alpha and beta ( II) adrenergic receptors → vasodilation and d intropy
Treats many tachyarrhythmias: atrial flutter, atrial fibrillation, vtach, ventricular flutter, SVT
Pharmacokinetically unique: absorbed slowly, deposits adipose tissue
Half life 25-60 days → cannot easily diminish or reverse effects
Side effects: pulmonary (pneumonia, pul fibrosis); cardiac (brady, arrhythmias, long QT, TdP); thyroid (due to iodine); GI; CNS
Amiodarone
Wide range effects through many mechanisms
sinus node firing; s automaticity; s reentrant circuits; Na, K, and Ca alpha and beta adrenergic receptors vasodilation and intropy
Treats many tachyarrhythmias: atrial flutter, atrial fibrillation, vtach, ventricular flutter, SVT
Pharmacokinetically unique: absorbed slowly, deposits adipose tissue
Half life 25-60 days
Side effects: pulmonary (pneumonia, pul fibrosis); cardiac (brady, arrhythmias, long QT, TdP); thyroid (due to iodine); GI; CNS
High rates torsades de pointes
Dronedarone (amiodarone analog without iodine)
Gastrointestinal side effects but not TdP
Sotalol
Calcium L-type Ca2+
Most effective cells dependant on Ca (SA, AV nodes)
transmission through AV node (for rapid atrial pulses)
Terminates reentrant rhythms
Treats AV nodal reentrant tachycardia (primary treatment)
Side effects: hypotension and heart failure pts taking beta-ers
Diltiazem and Verapamil
Digoxin
Inhibits activity sodium potassium pump (Na+-K+ ATPase inhibitor)
Treats heart failure complicated with atrial fibrillation (by decreasing heart rate)
s vagal tone; reduces sympa tic activity
Opens potassium (K+ activator)
Intravenously with saline flush (short 10 s half life)
Hyperpolarizes cells
Allows for rapid termination reentrant supraventricular tachycardia
chemical defibrillator

[@beachtime1419]

BEST video I have found for anti arrhythmic drugs! Thanks!

[@lewisbrown890]

This is the best anti arrhythmic lecture I've seen!

[@786abcfull]

Thanks for going into the actual chemistry of how they work.

[@helengao2124]

OMG thank you so much this is exactly what i need

[@crystelita767]

Thank you!!!!!

[@adaobisdiary5897]

You are the best. Please keep making more videos on pharmcology. This video was a great help in my exam

[@sunc88]

Thank you for great video!!! It’s really helpful!

[@user-mk2tb1kq2w]

Good job 👏👏

[@karolinaannasnarska2583]

so awesome. Thank you :D

[@mikewest9159]

Short n sweet…..very good

[@user-hs5sk4ym2g]

Increasing the electrical threshold will make it harder for cells to depolarize and generate an action potential

[@dinnysusan1685]

I got what I was looking for … thanks a lot

[@irunhurdles]

I am in nursing school and this just made my homework for those drugs easy!! Bam, short to the point. Thank you

[@pedro7401]

Last year I tryed one drug, don't remember the name, it was amazing I could finnaly practice sports but with time my tension dropped alot to the point I barely made it out of bed, I quite instantly. But those 3 weeks were the best I had

[@ivanlibre6297]

Very Understandable!

[@arunjkumar1760]

thank you!!

[@ahmadayyash3032]

Thank you Best video I have seen Thank you

[@meaganveronica94]

thank you!

[@jamalsinjab5137]

Watching your video is just as good as reading a book .

[@thomasczthomash1859]

Better than

[@طبيعى]

Thanks

[@RaviGupta-mh2hw]

What is the difference between rate and rhythm control?

[@ningwei7190]

Thanks for the video, I wonder that is there any paper talking about side effects of anti arrhythmic drugs?

[@MdRoshid-ox9tm]

Good

[@aluda1417]

Interesting

[@user-dr7fw8pr6m]

thank you perfect video can someone answer this : slowing down the influx of sodium ions into cardiac muscle cells causing a decrease in the excitability of the cells it has a beta adrenergic blocker which can cause bradycardia and bronchospasm : sotalol propafenone verapamil mexitilene

[@gandibachi87]

at 4:25 you said they make it easier to depolarize the cells, don't you mean the opposite... aren't we trying not to depolarize the cell that easily

[@harrisonochieng8006]

I think he should have said it Makes it harder to Depolarise the Neuron since the Threshold Potential has been raised..

[@hanialkhatib6855]

Class IC has a minimal effect on AP

[@melaniemichalik7354]

What does action potential mean in this

[@ssabbatini1021]

I believe Sotalol is a class II drug no?

[@matamatason7213]

It's a beta blocker class i yes but it's effects are of class iii... Hence its often listed twice both in class ii and class iii

[@hemantfarkade2661]

😱😱😱😱😱😱😱

[@beyondspace3736]

why don't they stop the heart and restart it . it will go back to normal

[@drxraghvendragautam4019]

Ok

[@TheegirlTasha]

Thank you it was very helpful 🤍🤍🤍 enough information in just 11 minutes

[@hemantfarkade2661]

aewHad