Management of congestive heart failure SA

Question 1

Outline 6 general principles of drugs used to manage congestive heart failure

Answer 1

1. Preload reduction & control of effusions (diuretics, +/- venodilators)
2. Afterload reduction (vasodilators)
3. Positive inotropic support (sympathomimetics, inodilators)
4. Improve diastolic function (negative inotropes, negative chronotropes)
5. Management of significant arrhythmias (Vaughan –Williams anti-arrhythmics Class 1,2,3 & 4)
6. Control of cardiac remodelling (Angiotensin converting enzyme inhibitors, spironolactone, Angiotensin receptor blockers)

Question 2

What type of drugs can be used to reduce preload. Give an example

Answer 2

Loop diuretics: furosemide or torasemide

Spironolactone is a weak diuretic but is used to spare furosemide, reduce hypokalaemia and to counter remodelling (aldosterone antagonist)

Question 3

In what situations are loop diuretics contra indicated

Answer 3

Only contra-indication is CHF secondary to cardiac tamponade

Question 4

What type of drugs can be used to reduce afterload. Give an example

Answer 4

Vasodilators- ACE inhibitors, amlodipine, hydralazine
Angiotensin converting enzyme inhibitors- benazepril, ramipril, enalapril
Pimobendan - Inodilator

Question 5

What type of drugs can be used to provide Positive inotropic support. Give an example

Answer 5

Pimobendan – positive inotrope and vasodilator (‘inodilator’) (IV bolus /continuous rate infusion or ORAL)

Digoxin – poor positive inotrope but good negative chronotrope (ORAL); narrow therapeutic margin

Dobutamine infusion - expensive, will buy some time for a patient with severe systolic failure (IV continuous rate infusion)

Question 6

What is the difference between Pimobendan and Digoxin

Answer 6

Pimobendan – positive inotrope and vasodilator (‘inodilator’) (IV bolus /continuous rate infusion or ORAL)

Digoxin – poor positive inotrope but good negative chronotrope (ORAL); narrow therapeutic margin

Question 7

What type of drugs can be used to Improve diastolic function. Give an example

Answer 7

Positive lusitropes (improve relaxation):
diltiazem
pimobendan

Negative chronotropes (decrease heart rate):
beta-blockers
diltiazem

Negative inotropes (decrease contractility):
beta-blockers
diltiazem

Question 8

What type of drugs can be used to Management of significant arrhythmias. Give an example

Answer 8

Digoxin
Negative inotropes

Question 9

What type of drugs can be used to Control remodelling of the heart. Give an example

Answer 9

ACE inhibitors
Spironolactone
Pimobendan

Question 10

T/F Congenital disease like Patent ductus arteriosus andPulmonic stenosis can be cured

Answer 10

True!

Question 11

T/F Acquired diseases such as Pericardial effusions, Tachycardia induced cardiomyopathy, Heart block related CHF and parasites can be cured

Answer 11

True!

Question 12

A dog has a murmur and cardiomegaly. Where does it sit on the AHA classification system

Answer 12

B2

Question 13

What drugs should be given to a dog on the AHA class system of A

Answer 13

No drugs! Just educate and monitor

Question 14

What drugs should be given to a dog on the AHA class system of B2

Answer 14

Pimobendan

Question 15

What level of NT-proBNP of a stage B2 dog would suggest CHF imminent in 6-12 months

Answer 15

> 1500

Question 16

What level of NT-proBNP will suggest a dog has CHF

Answer 16

> 2500

Question 17

What drugs Should be given to a dog on the AHA class system of C

Answer 17

Furosemide/torasemide
Pimobendan
ACE inhibitor
Spironolactone
+/- antiarrhythmics if required

Question 18

Management of a dog on the AHA class system of D

Answer 18

Consider additional diuretics- amiloride+hydrochlorthiazide (off license)
Torasemide if not already in use
Increase dose
Reconsider antiarrhythmic therapy
Consider specific treatment for pulmonary hypertension if present e.g. sildenafil
Consider antitussives eg codeine

Question 19

Acute Treatment in Hospital of a dog on the AHA class system of D

Answer 19

IV frusemide boluses/Continuous iv infusion (CRI)
Glyceryl trinitrate ‘Percutol’ (venodilator; off license)
Oxygen
IV pimobendan
IV dobutamine (off license)
Additional afterload reduction e.g. if ruptured chorda: amlodipine, hydralazine
Thoracocentesis if needed
Rarely abdominocentesis
Antiarrhythmic therapy if needed – IV or oral

Question 20

T/F All antiarrhythmics except digoxin are postive inotropes

Answer 20

False! All antiarrhythmics except digoxin are negative inotropes

Question 21

Is digoxin a positive or negative inotrope

Answer 21

Positive (quite weak)

Question 22

Name drugs to give for Supraventricular tachycardia / atrial fibrillation

Answer 22

Digoxin (off license)
Atenolol (off license)
Diltiazem modified release (off license)

Question 23

Name drugs to give for Ventricular arrhythmias

Answer 23

Lidocaine (IV)
Mexiletine (off license)
Atenolol (off license)
Sotalol (off license)
Amiodarone (off license)

Question 24

Describe dietary changes if a dog is on class C and D

Answer 24

Avoid excessive salt intake, especially salty treats
Monitor serum potassium: may need to supplement especially if inappetant, or on high dose diuresis
Feed diets rich in omega 3s
Make sure adequate calorie intake to try to avoid cardiac cachexia
Small and frequent, appetising, calorie dense diets best

Question 25

How often should a dog on Class C be checked

Answer 25

3 months

Question 26

How often should a dog on Class D be checked

Answer 26

1-2 months

Question 27

What should I give a cat with Feline cardiomyopathy Class B2

Answer 27

Clopidogrel
Aspirin
Rivaroxaban

Question 28

What should I give a cat with Feline cardiomyopathy Class C/D

Answer 28

Aspirin or clopidogrel or ? Rivaroxaban (off license)
Diuretics
furosemide or torasemide (off license)
+/- spironolactone
+/- ACE inhibitors
+/- Pimobendan (off license)