Cardiac Arrhythmia Pharmacology: Atropine, Class I-IV Drugs, and Atrial Fibrillation Management

Sinus Bradycardia treatment

Atropine

Atropine MOA

muscarinic antagonist that increases HR

Atropine side effects

causes tachycardia, flushed/hot skin

Slow cardiac action potentials

tachyarrhythmia caused by AV and SA node

FAST CARDIAC ACTION POTENTIALS

tachyarrhythmias in fibers of the His-Purkinje system and in atrial and ventricular muscle.

Class I antiarrhythmic

Sodium channel blockers

Sodium channel blockers

Lidocaine

Lidocaine MOA

antiarrhtymic medication that slows impulse conduction in atria, ventricels and His-Purkinje system

Lidocaine uses

used to treat V-tach and V-fib

Class II Antiarrhythmic

beta blockers

Beta Blocker MOA

slows HR by reducing SA node firing and slowing the AV node; reduces contractility

Class III antiarrhythmic

Potassium channel blockers

Amiodarone MOA

Potassium channel blocker that delays repolarization of fast potentials, therefore prolonging the action potential

Amiodarone uses

used to treat A-fib, A-flutter, V-tach, or V-fib

Amiodarone IV side efects

can cause Hypotension, bradycardia, phelbitis, toxic

Class IV Antiarrhythmic

Calcium channel blockers

calcium channel blocekrs

Verampamil, Dilitazem

calcium channel blocker MOA

Delay contraction through the AV node

calcium channel blocker adverse effects

can cause bradycardia and hypotension

Calcium channel blocker uses

used to treat Sinus tach, SVT, A-fib, A-flutter

Adenosine

rapid IV-push Anti-arrhythmic that slowing/blocking AV node electrical conduction

Adenosine Contraindications

cannot be given to patients with asthma

Adenosine side effects

Can cause sweating, flushing, headache, and metallic taste

SVT

tachycardia up to 300 bpm with absent P-waves

Atrial fibrillation

rapid/random contractions of atria > 350-600; irregular rhythm with non-identifiable P-waves

Atrial flutter

Atrial rate > 250-350 bpm; saw tooth wave pattern

Non-pharm SVT treatment

treat with a cardioversion or vagal maneuvers

A-fib/flutter rate control

give beta blockers or Calcium channel blockers

A-fib/flutter rhythm control

Give Amiodarone or do a cardioversion/ablation

Stroke prevention in A-fib/flutter

give antithrombotic agents: IV heparin or PO warfarin

IV Dopamine/EPi

used to treat severe hypotension or sinus bradycardia