Management of congestive heart failure SA Flashcards
Outline 6 general principles of drugs used to manage congestive heart failure
- Preload reduction & control of effusions (diuretics, +/- venodilators)
- Afterload reduction (vasodilators)
- Positive inotropic support (sympathomimetics, inodilators)
- Improve diastolic function (negative inotropes, negative chronotropes)
- Management of significant arrhythmias (Vaughan –Williams anti-arrhythmics Class 1,2,3 & 4)
- Control of cardiac remodelling (Angiotensin converting enzyme inhibitors, spironolactone, Angiotensin receptor blockers)
What type of drugs can be used to reduce preload. Give an example
Loop diuretics: furosemide or torasemide
Spironolactone is a weak diuretic but is used to spare furosemide, reduce hypokalaemia and to counter remodelling (aldosterone antagonist)
In what situations are loop diuretics contra indicated
Only contra-indication is CHF secondary to cardiac tamponade
What type of drugs can be used to reduce afterload. Give an example
Vasodilators- ACE inhibitors, amlodipine, hydralazine
Angiotensin converting enzyme inhibitors- benazepril, ramipril, enalapril
Pimobendan - Inodilator
What type of drugs can be used to provide Positive inotropic support. Give an example
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)
What is the difference between Pimobendan and Digoxin
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
What type of drugs can be used to Improve diastolic function. Give an example
Positive lusitropes (improve relaxation):
diltiazem
pimobendan
Negative chronotropes (decrease heart rate):
beta-blockers
diltiazem
Negative inotropes (decrease contractility):
beta-blockers
diltiazem
What type of drugs can be used to Management of significant arrhythmias. Give an example
Digoxin
Negative inotropes
What type of drugs can be used to Control remodelling of the heart. Give an example
ACE inhibitors
Spironolactone
Pimobendan
T/F Congenital disease like Patent ductus arteriosus andPulmonic stenosis can be cured
True!
T/F Acquired diseases such as Pericardial effusions, Tachycardia induced cardiomyopathy, Heart block related CHF and parasites can be cured
True!
A dog has a murmur and cardiomegaly. Where does it sit on the AHA classification system
B2
What drugs should be given to a dog on the AHA class system of A
No drugs! Just educate and monitor
What drugs should be given to a dog on the AHA class system of B2
Pimobendan
What level of NT-proBNP of a stage B2 dog would suggest CHF imminent in 6-12 months
> 1500
What level of NT-proBNP will suggest a dog has CHF
> 2500
What drugs Should be given to a dog on the AHA class system of C
Furosemide/torasemide
Pimobendan
ACE inhibitor
Spironolactone
+/- antiarrhythmics if required
Management of a dog on the AHA class system of D
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
Acute Treatment in Hospital of a dog on the AHA class system of D
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
T/F All antiarrhythmics except digoxin are postive inotropes
False! All antiarrhythmics except digoxin are negative inotropes
Is digoxin a positive or negative inotrope
Positive (quite weak)
Name drugs to give for Supraventricular tachycardia / atrial fibrillation
Digoxin (off license)
Atenolol (off license)
Diltiazem modified release (off license)
Name drugs to give for Ventricular arrhythmias
Lidocaine (IV)
Mexiletine (off license)
Atenolol (off license)
Sotalol (off license)
Amiodarone (off license)
Describe dietary changes if a dog is on class C and D
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
How often should a dog on Class C be checked
3 months
How often should a dog on Class D be checked
1-2 months
What should I give a cat with Feline cardiomyopathy Class B2
Clopidogrel
Aspirin
Rivaroxaban
What should I give a cat with Feline cardiomyopathy Class C/D
Aspirin or clopidogrel or ? Rivaroxaban (off license)
Diuretics
furosemide or torasemide (off license)
+/- spironolactone
+/- ACE inhibitors
+/- Pimobendan (off license)
