CV: Antiaarythmic - Flashcards
define aarythmia
any abnormal pattern of electrical activity in the heart
what happens with aarythmia?
abnormal heart muscle cells depolarize faster than SA node
what are three examples of sodium influx inhibitors?
lidocaine
quinidine
procainamide
what do sodium influx inhibitors do?
inhibit the movement of sodium ions across damaged cell membranes, this decreases the rate at which abnormal cells can depolarize
what does lidocain treat?
ventricular aarythmias
what are two types of ventricular aarthmyias that lidocain treats?
ventricular tachycardia and ventricular premature contractions
how is lidocain administered and why
IV because oral absorption is poor and IM is erratic
what animal is very suceptable to lidocain?
cats
large doses of lidocain may cause what?
sedation
toxic doses of lidocain may cause what?
CV shock and siezures
do not use lidocain mixed with what when treating arrhythmias IV?
epinephrine
when is procainamide and quinidine used?
when ventricular aarythmia has not resolved with lidocain
what are the side effects of quinidine?
vomitting diarrhea anorexia
what are two calcium channel blockers?
diltiazem and verpamil
what do calcium channel blockers do?
block movement of calcium across channels in the cell membrane decreasing the rate of depolarization of abnormal cells
what are two possible side effects of calcium channel blockers?
may decrease contractility of cardiac muscle and cardiac output
what are calcium channel blockers used to treat in cats? 2
tachyaarythmias and hypertrophic cardiomyopathy
what are calcium channel blockers used to treat in dogs?
tachyaarythmias
what do beta blockers do?
block the sympathetic nervous system receptors in the heart that increase the heart rate when stimulated
why would you use beta blockers?
because slowing the contraction rate if a diseased heart reduces the risk of arrythmias caused by abnormal cells
what is the most common antiarrythmic drug?
beta blockers
what are beta blockers used for in cats?
used to treat tachycardia in cats with hypertrophic cardiomyopathy
why can bronchioconstriction occur with the use of beta blockers/
its due to the blockage of the sympathetic stimulation at the bronchiole
with beta blockers, decreased sympathetic stimulation can also cause what? 2
decreased cardiac contractility
bronchioconstriction