Antiarrhythmics

Question 1

What is the MOA of class 1a and 1b antiarrhythmics?

Answer 1

Na+ channel blockers

Question 2

What is the MOA of class 2 antiarrhythmics?

Answer 2

Beta blockers

Question 3

What is the MOA of class 3 antiarrhythmics?

Answer 3

Potassium (K+) channel blockers

Question 4

What is the MOA of class 4 antiarrhythmics?

Answer 4

Calcium channel blockers

Question 5

What is the MOA of Lidocaine and what class does it fall under?

Answer 5

Class 1b - Na+ channel blocker

Question 6

What is the MOA of Diltiazem and what class does it fall under?

Answer 6

Class IV - Calcium channel blocker

Question 7

What is the MOA of Quinidine and what class does it fall under?

Answer 7

Class 1a - Na+ channel blocker

Question 8

What is the MOA of Sotalol and what class does it fall under?

Answer 8

Class III - Potassium channel blocker

also has some non selective Beta blocker effects

Question 9

What is the MOA of Amiodarone and what class does it fall under?

Answer 9

Class III - Potassium channel blocker

Question 10

What is the MOA of Procainamide and what class does it fall under?

Answer 10

Class 1a - Na+ channel blocker

Question 11

What is the MOA of propanolol and what class does it fall under?

Answer 11

Class II - non selective Beta blocker

Question 12

What is the MOA of Esmolol and what class does it fall under?

Answer 12

Class II - selective B1 blocker

Question 13

What is the MOA of Atenolol and what class does it fall under?

Answer 13

Class II - selective B1 blocker

Question 14

What is the MOA of Metoprolol and what class does it fall under?

Answer 14

Class II - selective B1 blocker

Question 15

Which of the following antiarrhythmics has both Beta and Alpha antagonistic effects?

Answer 15

Carvedilol

Question 16

What is the MOA of Carvedilol and what class does it fall under?

Answer 16

Class II -

non selective Beta blocker, and selective A1 antagonist

Question 17

What is the MOA of Mexilitine and what class does it fall under?

Answer 17

Class 1b - Na+ channel blocker

Question 18

What is the DOC for atrial fibrillation in horses?

Answer 18

Quinidine

-class 1a Na+ channel blocker

Question 19

What is the 1st line antiarrhythmic for v-tach in cats?

Answer 19

Procainamide

-class 1a Na+ channel blocker

Question 20

What is the DOC for treatment of V-tach in most species?

Answer 20

Lidocaine

-class 1b Na+ channel blocker

Question 21

What side effects can be seen with use of Mexilitine?

Answer 21

High bolus dosing can cause seizures, ataxia, twitching, GI signs

Question 22

Which antiarrhythmic are cats more sensitive to, requiring a fraction of the dose used in dogs?

Answer 22

Lidocaine

Question 23

Which of the following Na+ channel blockers comes in an oral formulation that can be taken home by the owner to control v-tach?

Answer 23

Mexilitine

Question 24

List the non-selective beta blockers

Answer 24

1. Propanolol
   - has some B2 antagonist effects
2. Carvedilol
   - has some a1 effects

Question 25

List the selective B1 blockers

Answer 25

1. Esmolol 2. Atenolol 3. Metoprolol

Question 26

What adverse effects can be seen with Amiodarone?

Answer 26

- **Type I hypersensitivity with IV admin** - Bone marrow suppression - Hepatotoxic - GI signs - Interferes with thyroid

Question 27

What is the DOC for treatment of supraventricular tachycardia due to an increased ventricular response rate?

Answer 27

Diltiazem (Class IV, Calcium channel blocker)

Question 28

List all the antiarrhythmics used to treat v-tach

Answer 28

1. Lidocaine (DOC) 2. Procainamide 3. Mexilitine 4. Sotalol 5. Amiodarone 6. Magnesium sulfate IV

Question 29

List all the antiarrhythmics used to treat supraventricular tachycardia

Answer 29

1. Diltiazem (DOC) 2. Digoxin 3. Quinidine (DOC for a-fib in horses) 4. Esmolol (short acting) 5. Propanolol 6. Atenolol 7. Metoprolol

Question 30

All of the following Na+ channel blockers can be used to treat v-tach EXCEPT? A. Lidocaine B. Quinidine C. Mexilitine D. Procainamide

Answer 30

B. Quinidine - used to treat a-fib in horses (SVT)

Question 31

All of the following are beta blockers used to treat supraventricular tachycardia EXCEPT? A. Propranolol B. Atenolol C. Carvedilol D. Metoprolol

Answer 31

C. Carvedilol

Question 32

Main uses of propranolol?

Answer 32

- Supraventricular tachycardia (SVT) - Tx of catecholamine induced tachyarrhythmias - HCM in cats secondary to hyperthyroidism

Question 33

Which of the following beta blockers has the shortest duration of action? A. Propranolol B. Atenolol C. Esmolol D. Metoprolol

Answer 33

C. Esmolol

Question 34

Which antiarrhythmic would you avoid if you are concerned about bronchoconstrictive effects? A. Propranolol B. Atenolol C. Esmolol D. Metoprolol

Answer 34

A. Propranolol **non selective Beta blocker** can cause bronchoconstriction (B2 antagonist)

Question 35

What is the main use of esmolol?

Answer 35

short term tx of SVT or to determine id beta blockers are effective for controlling the arrhythmia

Question 36

Main use of carvedilol?

Answer 36

useful in heart failure to treat DCM

Question 37

When are calcium channel blockers indicated?

Answer 37

Only for supraventricular tachyarrhythmias (Diltiazem)

Question 38

What are the contraindications of Diltiazem use?

Answer 38

- Don't use if pulmonary edema is present - Dont use is already hypotensive - Must give IV formulation slowly

Question 39

Main use of Sotalol?

Answer 39

Oral formulation to manage ventricular tachyarrhythmias

Question 40

Atrial standstill due to severe hyperkalemia can be treated with what drugs?

Answer 40

- IV calcium gluconate - IV sodium bicarb - dextrose - insulin

Question 41

What drugs can be used to treat 2nd degree AV block?

Answer 41

- Atropine response test - Isoproterenol - Theophylline - Glucagon

Question 42

What drugs can be used to treat sinus bradycardia?

Answer 42

1. Atropine 2. Glycopyrrolate (PNS-lytics)

Question 43

Which of the following antiarrhythmics would be best to give to a cat with HCM secondary to hyperthyroidism? A. Sotalol B. Propanolol C. Enalapril D. Lidocaine

Answer 43

B. Propanolol

Question 44

Main uses of atenolol?

Answer 44

- Tx of hypertension and tachyarrhythmias - Tx of subaortic stenosis - Safer in patients with bronchoconstrictive dz

Question 45

Which of the following beta blockers can be used to treat both ventricular and supraventricular tachyarrhythmias?

Answer 45

Metoprolol

Question 46

When are beta blockers contraindicated?

Answer 46

- Not used in cases of heart failure, pulmonary edema or CHF

Question 47

Which of the following is a selective beta adrenergic antagonist? A. Quinidine B. Atenolol C. Carvedilol D. Sotalol

Answer 47

B. Atenolol

Question 48

Which of the following is least appropriate to use for treatment of ventricular arrhythmias? A. Mexilitine B. Sotalol C. Amiodarone D. Diltiazem

Answer 48

D. Diltiazem

Question 49

What 2 drugs are used for atrial fibrillation in small animals?

Answer 49

Diltiazem and Digoxin

Question 50

Which of the following antiarrhythmics comes in an extended release formulation that has a risk for overdose and lethal toxicity?

Answer 50

Diltiazem

Question 51

Main uses of magnesium sulfate IV?

Answer 51

- Tx of refractory ventricular arrhythmias - Tx of malignant hyperthermia - Tetanus in dogs (NM blocking activity)