Anti-Arrhythmics Flashcards
what’s the goal of arrhythmia drugs?
reduce ectopic pacemaker activity
modify conduction or refractory to disable reentry
what do class I anti-arrhythmics do?
block Na+ channels
what do class IA anti-arrhythmics do?
blocks OPEN/ACTIVATED Na+ channels
what do class IB anti-arrhythmics do?
blocks INACTIVE Na+ channels
what do class IC anti-arrhythmics do?
blocks both open and closed Na+ channels
what do class II anti-arrhythmics do?
reduce adrenergic activity of heart
what do class III anti-arrhythmics do?
K+ channel block
what do class IV anti-arrhythmics do?
Ca2+ channel block
Quinidine is a class ___, ___ block
class IA
Na+ block
**also blocks M and alpha receptors
Quinidine indications
supraventricular and ventricular arrhythmias
Tx re-entrant arrhytmia (atrial fibrillation)
in dogs and horses
Quinidine binds to Na+ ___ channel to slow AP
active Na+ channels
what are the adverse effects of Quinidine based on each receptor it affects (alpha, M)?
alpha - hypotension, reflex tachy
M - increases HR, increase AV conduction
Quinidine adverse effects on dog vs horse
dogs - anorexia, V, negative inotropism
horse - colic, ataxia, nasal swell
Quinidine contraindications
myasthenia gravis
AV block
digitalis toxicity or on digotoxin
Procainamide is a class ___, ___ block
class IA
active Na+ block
Procainamide indications
ventricular arrhythmia
*NOT very effective in horse