Flashcards in CV Drugs 2 Deck (37):
what are the mechanisms of arrhythmias
-disturbances in both automaticity and impulse conduction
class I antiarrhythmic drugs =
sodium channel blockers, prolongs AP
what is the drug of choice to treat atrial fibrillation in horses?
it's possible to use quinidine for ventricular arrhythmias but what class IA drug would be a better choice?
procainamide, more effective
T/F: class IA sodium channel blockers shorten APs while class IB sodium channel blockers prolong APs
what class IB sodium channel blocker is the drug of choice for treatment of ventricular tachycardia in dogs?
lidocaine (cats are sensitive! watch dosing)
T/F: its always safer to treat for ventricular tachycardia
TRUE! lidocaine has very short half life
what sort of effect do class II beta-blockers have?
inhibition of catecholamine effects on the heart
of the class II beta-blockers that are selective B1 antagonists, which is used in the treatment of HCM in cats
what are the three class II beta-blockers that are selective B1 antagonists?
esmolol (short-term), atenolol, and metoprolol
why should you wean off class II beta-blockers gradually?
risk of upregulation of receptors ("sympathetic storm")
when are class II beta-blockers contraindicated?
is unstable or overt heart failure present
in what type of patient do you see more adverse effects of class II beta-blockers?
geriatric or unstable patients (hypotension, lethary, depression, syncope, worsening CHF)
what type of class II beta blockers are safer to use in patients w/ bronchoconstrictive disease?
selective B1 antagonism
T/F: some adverse effects of amiodarone include GI, bone marrow suppression, hepatotoxicity, type I hypersensitivity w/ IV formulation
what class III K channel blocker is used for the treatment of ventricular arrhythmias in dogs and is often a 2nd or 3rd line antiarrhythmic?
amiodarone, limited use in horses, converts atrial fibrillation to sinus rhythm
sotalol is a class III K channel blocker, what other type of blocker is it?
T/F: amiodarone is contraindicated with overt or low output CHF
which class III potassium channel blocker has more side effects?
match the blockers to the class
class I beta blockers
class II ca channel blockers
class III k channel blockers
class IV na channel blockers
class I=na channel blockers
class II=beta blockers
class III=k channel blockers
class IV=ca channel blockers
what type of arrhythmia are ca channel blockers indicated for?
supraventricular arrhythmias ONLY
what two anti-arrhythmic drugs are used in combination w/ horses to treat SVT?
quinidine (class IA na channel blocker) and diltiazem (class IV: ca channel blocker)
what is the drug of choice for treatment of SVT and to decrease ventricular response rate in treatment of atrial fibrillation?
what drug in what class has the greatest effects on the SA and AV nodes?
what class of antiarrhythmics are contraindicated with radiographically documented pulmonary edema?
class IV calcium channel blockers
T/F: diltiazem when given IV should be given very slowly
nothing is working!! how can i try to stop SVT in a patient w/ no drugs?
vagal maneuvers (carotid sinus massage, ocular pressure)
T/F: hypovolemic patients can lead to fluid-responsive tachycardia
what three drugs would you consider for treating a 2nd degree AV block?
what two drugs would you consider for treating sinus bradycardia?
**do nothing! often underlying cause can't be treated w/ drugs alone
what would indicate an atrial standstill on an ECG?
absence of p-waves
T/F: atrial standstill is most commonly caused by severe hyperkalemia
which of the following is considered the drug of choice for treatment of ventricular tachycardia?
a. lidocaine, mexilitine is the oral form
which of the following is considered a drug of choice fro treatment of atrial fibrillation with high ventricular response rate?
which of the following if best described as a selective beta-adrenergic antagonist?
which of the following if least appropriate to use for treatment of ventricular arrhythmias?