Antiarrhythmic drugs Flashcards
Impulse propagation depends on –
conduction velocity and gNa+
conduction velocity depends on -
intracellular resistance and gNa+
gNa+ depends on
transmembrane [Na+] gradient and state of Na+ channel readiness
shortest interval at which a premature stimulus results in a propagated response
effective refractory period
sodium channel blockade
quinidine, lidocaine, encainide
beta-adrenergic blockade
propranolol
moderate phase-0 depression and slow conduction (usually long repolarization)
quinidine
minimal phase-0 depression and slow conduction (usually shorten repolarization)
lidocaine
marked phase-0 depression and slow conduction (little effect on repolarization)
encainide
prolong repolarization
amiodarone (and quinidine)
Ca2+ channel blockade
verapamil, diltiazem
adenosine, digitalis glycosides are – drugs
miscellaneous
Class IA antiarrhytmic drugs
quinidine
What does quinidine block (class IA)?
use-dependent block of Na+ channels
Class IA (quinidine) drugs have a similar action on the heart as –
peripheral nerves
Difference between the action of peripheral nerves and Class IA (quinidine) on the heart
Class IA (quinidine) affect the heart at lower concentrations