Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
What are class 1a drugs?
|
Sodium channel blockers that work by prolonging the action potential duration and decrease the slope of phase 0.
Quinidine Procainamide |
|
|
What can you treat using class 1a drugs?
|
Ventricular tachycardia
VPC Reentry pathways Supraventricular tachycardias such as atrial fibrillation |
|
|
What are class 1b drugs?
|
Sodium channel blockers that work by decreasing the slope of phase 4, which slows automaticity, and also shortens the action potential duration.
Lidocaine Mexiletine |
|
|
Indications for lidocaine?
|
Ventricular arrhythmias
Reentry pathways High vagal tone causing atrial fibrillation Has highest effect on damaged myocardial tissue |
|
|
Indications for mexiletine?
|
Long term control of ventricular arrhythmias that are responsive to lidocaine
|
|
|
What are class 2 drugs?
|
Beta-adrenergic receptor blockers which decrease automaticity by blocking sympathetic tone, interrupts reentry by prolonging refractory of the AV node, and by decreasing AV node refractoriness, slowing ventricular response to atrial tachycardias.
Propanolol Atenolol |
|
|
What are indications for class 2 drugs?
|
Atrial tachycardia and fibrillation (if refractory to lidocaine)
Ventricular arrhythmias in combination with class 1 antiarrhythmics Occasionally in cats with sinus tachycardia or ventricular arrhythmias from hyperthyroidism. |
|
|
Contraindications for beta blockers?
|
Underlying myocardial disease
AV block CHF Diabetes Pulmonary disorders |
|
|
What are class 3 drugs?
|
Potassium channel blockers that work by prolonging the AP duration, which will interrupt reentry pathways and increase the ventricular fibrillation threshold. Also has Beta blockade effects.
Sotalol Amiodarone Bretylium |
|
|
Indications for class 3 drugs?
|
Life-threatening ventricular arrhythmias in dogs with underlying heart disease, such as DCM in boxers and dobies
|
|
|
What are class 4 drugs?
|
Calcium channel blockers
They act by slowing calcium entry into smooth muscle, producing vasodilation, and slowing conduction and reducing contractility. Depresses phase 4 and 0. Diltiazem Verapamil |
|
|
What are indications for using verapamil?
|
Reentry pathways that use the AV node
Decreases AV node refractoryiness Anti-hypertensive Terminates supraventricular tachycardias such as atrial fib or flutter Slows rapid ventricular rates |
|
|
What are indications for using diltiazam?
|
To slow or convert supraventricular tachycardias, including flutter and fibrillation.
Slow AV node conduction, thereby slowing rapid ventricular rates |
|
|
What is the MOA of digoxin?
|
Slows conduction through the AV node
Increases parasympathetic and reduces sympathetic tone on the AV node Positive inotrope Indicated for CHF or myocardial disease, prevention of supraventricular arrhythmias |
|
|
What are anticholinergic drugs? What are they used for?
|
Anticholinergics (atropine, glycopyrrolate) increase automaticity of the SA node and increase conductivity through the AV node
|
|
|
What are sympathomimetic drugs for?
|
Dopamine, terbutaline
They increase automaticity and increase the rate of escape beats. Used for bradycardias when pacemakers are not available. |
