Cardiology

Question 1

Chronotropic

Answer 1

affects the heart rate

Question 2

Inotropic

Answer 2

affecting the force of contraction

Question 3

Preload

Answer 3

amount of blood that fills the ventricle during diastole

Question 4

Afterload

Answer 4

arterial resistance that ventricle must pump against

Question 5

SNS –>

Answer 5

positive chronotropic and inotropic effects

Question 6

PSNS –>

Answer 6

negative chronotropic effects

Question 7

Positive Inotropes(increase the force)

Answer 7

1. Catecholamines
   - Uses: cardiac resuscitation and anaphylaxis

-Increases HR & force, vasoconstriction -> Increase BP

Dosage Forms:

• Epinephrine HC1 for injection
• Dopamine
• Dobutamine

2. Cardiac glycosides (Digitalis)
   - increases force and decrease rate of contraction/ increases level of calcium in cell

Uses: CHF, Arrhythmias
Dosage Form:
-Digoxin elixer (Cardoxin LS)

3. Inodilator

Uses: CHF, mitral valve disease

-Has both inotropic and vasodilator effects

Dosage Form:
-Pimobendan (Vetmedin)

Question 8

Antiarrhythmics (fix the rhythm)

Answer 8

Arrhythmia= any abnormal pattern of electrical activity in the heart

-4 basic categories of drugs

Question 9

Antiarrhythmics: Class 1 A

Answer 9

• Quinidine: treat atrial fibrillation

- Procainamide

Question 10

Antiarrhythmics: Class 1 B

Answer 10

• blocks the flow of sodium
• Lidocaine: local anesthetic and antiarrhythmics; administered IV. And used to control VPC’s and ventricular tachycardia

Question 11

Antiarrhythmics: Beta Blockers Class II

Answer 11

• Propranolol
• Atenolol

-Side Effects:bradycardia, hypotension, lethargy

Question 12

Antiarrhythmics: Calcium Channel Blockers Class IV

Answer 12

• Verapamil
• Diltiazem
• Amlodipine

Question 13

Special Concerns with antiarrhythmics

Answer 13

• Digoxin levels may increase in animals taking quinidine so dose may have to be lowered
• Reactions to procainamide are likely in animals sensitive to other “-caine” local anesthetics
• Be certain NOT to use the lidocaine product with epinephrine when giving IV

-Cats are sensitive to lidocaine so monitor closely
Because propranolol blocks beta-1 and beta-2, it affects heart (decrease HR & BP) and bronchi (bronchoconstriction)

Question 14

Vasodilators

Answer 14

• CHF causes increase preload and afterload and increase work on the heart
• Dilation of arteries and arterioles decreases afterload and also decreases preload
• Allows blood to flow more easily which reduces the work of the heart

Question 15

Arteriole Dilators

Answer 15

Uses: reduce afterload

Side Effects: GI and hypotension

Dosage forms: Hydralazine

Question 16

Venodilators

Answer 16

Uses: reduce preload

Side Effects: rash at application site, hypotension

Dosage Form: Nitroglycerine ointment or transdermal patch

Question 17

ACE inhibitors

Answer 17

• Vasodilators
• reduces both preload and afterload
• Angiotension Converting Enzyme Inhibitor
  
  • Enalapril
  • Benazepril
  • Captapril

Question 18

Diuretics

Answer 18

• reduce preload through diuresis
• most powerful: Furosemide; administered IV, IM, SQ, or orally
• main side effect: hypokalemia

Spironolactone: potassium sparing

Question 19

Ancillary Treatment

Answer 19

-Bronchodilators: aminophylline and theophylline

• oxygen therapy
• Aspirin: inhibits platelet aggregation to help decrease clot formation

-thoracocentesis and abdominocentesis