Antiarrhythmics

Question 1

Describe the characteristics of class 1a antiarrhythmics

Answer 1

Block sodium and potassium channels, depending on their concentration and patient’s heat rate

Question 2

List the three 1a antiarrhythmics

Answer 2

Quinidine, procainamide and disopyramide

Question 3

Describe the characteristics of class 1b antiarrhythmics

Answer 3

Block sodium channels in ischemic tissues. Primarily used for VT post MI because they do not act on atrial tissues. Effect is shortened QT interval.

Question 4

List the three 1b antiarrhythmics

Answer 4

lidocaine and mexiletine and tocainide

Question 5

Describe the characteristics of 1c antiarrhythmics

Answer 5

The most potent Na blockers; act as negative ionotropes and depress LV function.

Question 6

List the three 1c antiarrhythmics

Answer 6

flecainide, propafenone, moricizine

Question 7

Describe the characteristics of class II anyiarrhythmics

Answer 7

Beta-blockers

Question 8

Describe the characteristics of class III antiarrhythmics

Answer 8

Potassium channel blockers; deplay repolarization

Question 9

List the five class III antiarrhythmics in the notes

Answer 9

Amiodarone, bretylium, sotalol, ibutilide, dofetilide

Question 10

Describe the characteristics of class IV antiarrhythmics

Answer 10

Non-dihydropyridine Ca channel blockers; slow SA and AV node impulses (slow conduction and increase refractoriness) and has negative inotropic action. Used to treat SVT

Question 11

What are the two class IV antiarrhytimics in the notes?

Answer 11

Verapamil and diltiazem

Question 12

How does adenosine work to treat arrhythmias?

Answer 12

Works on adenosine receptors in atrium, SA and AV nodes. Activates K current and shortens AP; hyperpolarizing tissue and slowing automaticity and AV conduction.