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;
37 Cards in this Set
- Front
- Back
|
· Normal pacemaker myocyte depolarization |
...
|
|
|
· Normal contractile myocyte deplolarization
|
...
|
|
|
· What are the different classes of antiarrhythmic drugs?
|
Classes I, II, III, IV and "other"
|
|
|
What is the mechanism of action of class I antiarrhythmics?
|
Na+ channel blockade
|
|
|
What is the mechanism of action of class II antiarrhythmics?
|
Beta adrenergic receptor blockade
|
|
|
What is the mechanism of action of class III antiarrhythmics?
|
K+ channel blockade
|
|
|
What is the mechanism of action of class IV antiarrhythmics?
|
Ca++ channel blockade (L-type)
|
|
|
· What are the subclasses of class I antiarrhythmics?
|
o 1a, 1b, and 1c
|
|
|
· How are the subclasses of class I antiarrhythmics distinguished?
|
o All block Na+ channels but differ in their ability to block K+ channels
|
|
|
Name two class Ia antiarrhythmic drugs.
|
Procainamide
Quinidine |
|
|
· What is NAPA?
|
o N-acetyl procainamide (metabolite of procainamide)
|
|
|
· What are the effects of NAPA?
|
o NAPA has K+ channel blocking effects
|
|
|
· What is the prototypical class Ib antiarrhythmic?
|
o Lidocaine
|
|
|
· What is the prototypical class Ic antiarrhythmic?
|
o Flecainide
|
|
|
· What is the contraindication to flecainide and why?
|
Contraindicated in patients with underlying ischemic heart disease because of increased mortality
|
|
|
Name important class II antiarrhythmics.
|
Metoprolol. d,1 sotalol
|
|
|
Name the prototypical class III antiarrhythmic.
|
Amioderone
|
|
|
• Which endogenous molecule is amioderone structurally similar to?
|
Thyroxine
|
|
|
• What are the adverse effects of amiodarone?
|
o Amiodarone has a long half-life and poor solubility
o Deposits in the lung causing irreversible pulmonary damage o Deposits in the cornea causing visual disturbances o Deposits in the skin where it causes a bluish tinge |
|
|
Name the two principle class IV antiarrhythmics.
|
Verapamil
Diltiazem |
|
|
• Why does verapamil have relatively marked effects on the SA and AV nodes?
|
o Verapamil is an L-type calcium channel blocker, and the pacemaker cells of the SA and AV node are highly dependent on calcium currents
|
|
|
• What is the major adverse effect of verapamil?
|
o Inhibition of myocardial contractility
|
|
|
• What is the indication for class IV antiarrhythmics?
|
o Re-entrant supraventricular tachycardias
|
|
|
• Name three common antiarrhytmics that do not belong to classes I, II, III, or IV.
|
Adenosine
Furosemide Atropine |
|
|
• What is the duration of adenosine?
|
o Very short (approx. 10 seconds)
|
|
|
• What is the mechanism of action of adenosine?
|
• What is the mechanism of action of adenosine?
|
|
|
Assign the drug to the correct antiarrhytmic class.
Sotalol |
Class II (beta blocker)
|
|
|
Digoxin
|
"Other" (cardiac glycoside)
|
|
|
Propranolol
|
Class II (beta blocker)
|
|
|
Flecainide
|
Ic
|
|
|
Quinidine
|
Ia
|
|
|
Amiodarone
|
III
|
|
|
Verapamil
|
IV
|
|
|
Atropine
|
Other
|
|
|
Adenosine
|
Other
|
|
|
Procainamide
|
Ia
|
|
|
Lidocaine
|
Ib
|
