Antiarrhythmic Flashcards
Class I
Na Channel block (phase 0)
Class II
BB (sympathetic input/SA node)
Class III
prolong APD (inc ERP/block potassium)
Class IV
CCB
Class Ia
Moderate dissoc rate
Class Ib
Rapid dissoc
Class Ic
Slow dissoc
Class I is classified on
rate of dissociation from closed channels
state-dependent block means
binding to open or inactivated channels
association occurs in
systole
dissociation occurs in
diastole
Block related to depolarization
HR
ischemia
APD
what maintains block in normal
slowly dissociating (not rapid)
what maintains block in high HR, ischemia, prolonged APD
slow and rapid dissociation
Procainamide
Class Ia
Avoid in prolonged QT syndrome
Class Ia
torsades de pointes
Anticholinergic effect
Class Ia
Effect on AV node conduction with Class Ia
unpredictable
direct - decreases, antichol - increases
active metabolite of Procainamide
NAPA
ADR Procainamide
+ANA
Lupus like syndrome
Agranulocytosis/leukopenia
Proarrhythmic effect
CI for Procainamide
Prolonged QT
hypokalemia
SLE
Class Ib
Lidocaine
Mexiletine
Indications for Lidocaine
Life threatening V arrhythmias
Digoxin-induced arrhythmias
ADR - lidocaine
CNS (disorientation – seizures)
Hypotension
decrease cardiac contractility
CI - Lidocaine
hypersensitivy - amides
severe hepatic dysfunction
history of lidocaine-induced seizures