Anti Arrhythmics

Question 1

Which pacemaker node has the highest rate of automaticity?

Answer 1

The SA node

Question 2

List two mechanisms of cardiac arrhythmias

Answer 2

Slowed conduction causing reentry circuits, altered rate of spontaneous discharge (ectopic pacemaker)

Question 3

List class 1A, 1B, and 1C antiarrhythmics

Answer 3

1A: quinidine, disopyramide, procainamide
1B: lidocaine, mexiletine, tocainide, phenytoin
1C: Flecainide, propafenone

Question 4

List three features of class 1 antiarrhythmics

Answer 4

Sodium channel blockers, cause slow depolarization, contain MSA

Question 5

Describe the difference between lidocaine given injection and given IV

Answer 5

Injection – numbing effect

IV – antiarrhythmic effect

Question 6

Which type of class one antiarrhythmics are rarely used due to increased mortality in post MI patients?

Answer 6

Class 1C – slow sodium channel blockers (Flecainide, propafenone)

Question 7

Describe class II antiarrhythmics and list five examples

Answer 7

Beta adrenergic blockade used for atrial and ventricular arrhythmias
Propanolol, sotalol, esmolol, metoprolol, atenolol

Question 8

Describe class III antiarrhythmics and list 3 examples

Answer 8

Potassium channel blockers used for ventricular and atrial arrhythmias
Amiodarone, dofetilide, sotalol

Question 9

Describe class IV antiarrhythmics and list 2 examples

Answer 9

Calcium channel blockers used in supraventricular arrhythmias
Diltiazem and verapamil

Question 10

List 4 side effects of class 1A antiarrhythmics

Answer 10

Tachycardia, sedation, constipation, dry mouth

Question 11

Which class of antiarrhythmics are anti-cholinergic drugs?

Answer 11

IA: quinidine, procainamide, disopyramide

Question 12

What is one particular side effect of procainamide?

Answer 12

Lupus like syndrome: butterfly rash, arthralgias

Question 13

Which antiarrhythmic causes a lupus like syndrome?

Answer 13

Procainamide (IA)

Question 14

Which IB antiarrhythmic is IV, and which is PO?

Answer 14

IV – lidocaine

PO – mexiletine

Question 15

What is CAST & which class of drugs does it involve?

Answer 15

Cardiac arrhythmia suppression trial: showed increased mortality in post-MI patients with ventricular arrhythmias
(class 1C)

Question 16

Which class II antiarrhythmic is given IV?

Answer 16

Esmolol – short half-life, metabolized by plasma esterases

Question 17

List four adverse effects of amiodarone

Answer 17

Visual disturbances, blue discoloration to skin, thyroid disturbances (contains iodine), pulmonary fibrosis

Question 18

List reasons why amiodarone is commonly used to treat arrhythmias

Answer 18

Treats atrial and ventricular arrhythmias, can be used in heart failure, can be administered IV or PO, long half life with large volume of distribution

Question 19

What is Dronedarone?

Answer 19

Prodrug of amiodarone used in atrial arrhythmias

Question 20

How is Dronedarone different from amiodarone?

Answer 20

Lacks iodine that contributes to toxicity, cannot be used in patients with heart failure, only used in atrial arrhythmias

Question 21

Which antiarrhythmic class is sotalol, and what is special about sotalol?

Answer 21

Class III

Has beta blocking properties and potassium channel blocking properties

Question 22

What is digoxin mainly used to treat?

Answer 22

A fib and A flutter

Question 23

What is the drug of choice for torsades?

Answer 23

Magnesium sulfate

Question 24

What is the pharmacological rule about antiarrhythmic drugs?

Answer 24

All antiarrhythmics are arrhythmogenic