Cardio - Antiarrhythmics Flashcards
What are class I antiarrhythmics
Na channel blocker
Decrease slope of phase 0 depolarization
What are the class IA agents
Quinidine, procainamide, disopyramide
“The QUeen PROClaims DISO’s PYRAMID”
What is the effect of the class IA agents
Increase AP duration
Increase effective refractory period
Increase QT interval
What are the class IA agents used for
Atrial and ventricular antiarrhythmics
Especially reentrant and ectopic supraventricular and ventricular tachycardia
What are toxicities to class IA agents
Quinidine - headache, tinnitus
Procainamide - SLE like syndrome
Disopyramide - heart failure
All - thrombocytopenia and tosades de pointes
What are the class IB agents
Lidocaine, mexiletine, tocainide
“I’d Buy LIDy’s MEXIcan TaCos”
What is the effect of the class IB agents
Decrease AP duration
What are the class IB agents used for
Post MI
IB is Best post MI
What are class IC agents
Flecainide
Propafenone
What is the effect of the class IC agents
No effect on AP duration
What are the class IC agents used for
Ventricular tachycardias that progress to VF
What are toxicities to class IC agents
Contraindicated in structural heart disease and post-MI
What are the class II agents
Beta blockers (-olol)
What effect do the class II agents have
Decrease slope of phase 4
What are class II agents used for
Ventricular tachycardia, SVT, slowing ventricular rate during A-fib and A-flutter
What are side effects to class II agents
Impotence, exacerbation of asthma, CNS effects
What are the class III agents
K channel blockers
Amiodarone, ibutilide, dofetilide, sotalol
What is the mechanism of class III agents
Increase AP duration
What are class III agents used for
Used when other antiarrhythmics fail
What are side effects to class III agents
Sotalol/ibutilide - torsades de pointes
Amiodarone - hepatotoxicity, corneal deposits, skin deposits
What are the class IV agents
Ca channel blockers
Verapamil, Diltiazem
What is the mechanism of class IV agents
Decrease conduction velocity
What are toxicities to class IV agents
Constipation, flushing, edema
What is the mechanism of adenosine
Increase K out of cells hyperpolarizing the cell and causing decreased Ca
Toxicity - flushing, hypotension, chest pain
What is Mg used for
Torsades and digoxin toxicity
