Management of Heart Failure 1 and 2 Flashcards
Which types of drugs improve contractility?
- Positive inotropes:
- Digoxin (digitalis glycosides)
- Pimobendan (Vetmedin)
- Dobutamine
Effects of digoxin?
- Positive inotropic agent
- Negative chronotropic agent
- Increases vagal tone
- Decreases sympathetic tone
- Alters baroreceptor sensitivity
Side-effects of digoxin?
- Predominantly renal excretion (avoid drug or decrease dose in RF)
- Narrow therapeutic range - digoxin toxicity!
- Gastrointestinal side effects
- Induce dysrhythmias at higher doses
What are the clinical signs of digoxin toxicity?
Off food, lethargy, depression, borbgrgymi , arrhythmias can all occur before the classical V and D.
What are the recommended serum levels of digoxin?
- Measure serum digoxin level
- Aim for 0.5ng/ml – 1ng/ml
What are the effects of Pimobendan?
- Inodilator
- Calcium-sensitizing drug (Positive inotrope)
- PDE III inhibitors (Vasodilation)
- Antithrombotic activity
Which types of drug help the heart relax?
- Positive lusitropes:
- Calcium channel blockers (diltiazem, verapamil)
- Beta blocker (propranolol, atenolol)
What are the uses of Atenolol?
- Heart rate control
- Anti-arrhythmic
- Reduce LVOFTO
- Decrease myocardial oxygen demand
What are the goals of therapy for congestive heart failure?
- Control Salt & Water Retention
- Improve Pump Function
- Reduce Workload (decrease afterload, decrease physical activity and stress)
With ACVIM stage B1 heart patients (asymptomatic patients with no radiographic or echocardiographic evidence of cardiac remodelling), how would you manage these cases?
- No treatment - but consider
- Weight control
- Regular re-assessment
- Client education
With ACVIM stage B2 heart patients (asymptomatic patients with radiographic or echocardiographic evidence of left-sided heart enlargement), how would you manage these?
- No treatment - but consider
- Pimobendan
- Weight control
- Regular re-assessment
- Client education
With ACVIM stage C patients (clinical signs of congestive heart failure), how would you manage them?
- Remove fluid - diuretic traditionally used
- Act at kidney to increase urine output
Which types of diuretics are used in CHF?
- Loop
- Furosemide
- Torasemide
- Potassium Sparing
- Spironolactone
- Amiloride
- Thiazide
- Hydrocholorothiazide
Markers elevated in cardiac failure?
Natriuretic peptides – BNP, ANP
Markers elevated in myocardial disease?
- Troponins
- Important in human medicine
Which co-existing diseases may contribute to failure?
- Hypothyroidism
- Cushing’s disease
- Complications
- Renal insufficiency
- Hepatic insufficiency
- NB may affect treatment used
What can cause worsening of left-sided congestive heart failure despite therapy?
- Worsening of disease
- Rupture of CT, atrial tear
- Furosemide resistance?
- Compliance?
- R sided failure and poor GI drug absorption?
What would you do in a case of worsening left-sided congestive heart failure despite therapy?
- Changes to treatment
- Increase dose / frequency of frusemide
- Increase dose / frequency of ace inhibitors
- Increase dose of pimobendan
- Consider adding other drugs
- Antidysrhythmic / negative chronotropes
- Sildenafil if pulmonary hypertension
- Hydrochlorothiazides
- Omega 3 fatty acids
Emergency congestive heart failure therapy for decompensation?
- Furosemide
- Oxygen supplementation
- Pimobendan if systolic dysfunction (all CDVD and DCM cases)
- Cage rest
- Avoid stress
- Sedation as necessary (Butorphanol 0.1 - 0.2mg/kg)
- Glyceryl trinitrate ointment
- Monitor renal values / electrolytes
- Antidysrhythmic medication if necessary
What is an Intractable cough?
Cough despite standard therapy
Causes of an Intractable cough?
- Unstable LCHF
- Enlarged LA
- Bronchomalacia
- Chronic airway disease
Diagnosis of an Intractable cough?
Treatment of an Intractable cough if a result of unstable left-sided congestive heart failure?
- Further alterations to treatment regime
Treatment of an Intractable cough if a result of an enlarged left atrium?
- Reduce LA size with therapy
- Standard therapy
- Afterload reducers – amlodipine, hydralazine
- Bronchomalacia, airway collapse, concurrent bronchitis
- Bronchodilators
- Inhalers, theophylline
What should you stress the importance of to owners of animals in heart failure?
- A regular daily routine
- The administration of prescribed medication
- A consistent exercise schedule
- The possible side/toxic effects of medications
- Maintaining appetite
Problems with diuretics?
Volume depletion could cause…
- Potential hypovolaemia
- Cause/exacerbate azotaemia
- Stimulate RAAS
What is the viscious cycle of heart failure?
heart failure > decreased CO > compensatory mechanisms (increased sympathetic activity, increased RAAS, increased ADH) > excessive vasoconstriction, sodium and water retention > increased preload and afterload > continuous cycle
What do vasodilators do?
Dilate Arteries, Veins or Both
What do venous dilators do?
- Decrease preload
- Reduce fluid build up
- E.g. Glyceryl trinitrate
What do arterial dilators do?
- reduce afterload
- Increase output
- Reduce valve leakage
- E.g. Hyralazine
When is congestive heart failure treated and how?
- Class II and III
- Clinical signs of Congestive Heart Failure.
- Remove fluid
- Vasodilate
- ACE inhibitor now used
What do ACE inhibitors do?
- Theoretical benefits
- Veno and arterial vasodilation
- Decreased salt and water retention
- Local ACE and myocardial remodelling
- Causes efferent arteriolar dilation causing a reduced glomerular filtration rate
- (inhibit angiotensin converting enzyme from converting angiotensin I to angiotensin II and entering the RAAS system)
Describe how the RAAS increases BP?
- Angiotensinogen converted to Angiotensin I (by renin), then to Angiotensin II (by Angiotensin Converting Enzyme)
- Angiotensin II causes peripheral vasoconstriction = increased BP
- Angiotensin II also causes aldosterone secretion = salt and water retention = increased blood volume = increased BP
Contra-indications for ACE inhibitors?
- Fixed CO – AS, HOCM
- Renal dysfunction??
- K-sparing diuretics
- NSAIDs??
List ACE inhibitors.
- Imadipril
- Prilium
- Enalapril
- Enacard
- Benazepril
- Benfortin
- Nelio
- Prilben
- Fortekor
- Kelapril
- Ramipril
- Vasotop
- Causes efferent arteriolar dilation causing a reduced glomerular filtration rate
What should you bear in mind when using ACE inhibitors?
- Azotaemia
- Hypotension
- Monitor renal parameters regularly
- Benazepril may be more suitable for patients with renal disease, as less dependant on renal excretion
How is stage B2 and C (clinical signs of congestive heart failure) treated?
- Role of pimobendan (Vetmedin)
- Inodilator
- Positive inotrope
- Vasodilator
Activity of pimobendan?
- Inodilator
- Calcium-sensitizing drug
- Positive inotrope
- PDE III inhibitors
- Vasodilation
- Antithrombotic activity
- ‘Feel good’ factor ? mechanism
What is stage D heart failure classed as?
Stage D - Advanced
- Obvious clinical signs with minimal exercise
- Progressively worsens
- Obvious clinical signs at rest
- Progressively worsens
- Death
Goals of emergency CHF treatment?
- Treatment of life-threatening CHF is 1st priority!
- Take into consideration which other concurrent diseases may be present
- Current medication
What is used for emergency treatment of CHF?
- Furosemide
- 2mg/kg IV initally then
- 1mg/kg hourly afterwards until respiratory rate and effort reduce (up to 4 doses in cats more as necessary in dogs)
- Oxygen supplementation
- Pimobendan if systolic dysfunction (all CDVD and DCM cases)
- Cage rest
- Avoid stress
- Sedation as necessary (Butorphanol 0.1 - 0.2mg/kg)
- Glyceryl trinitrate ointment
- Monitor renal values / electrolytes
- Antidysrhythmic medication if necessary
- If blood pressure allows gradually start low dose ACEI and wean up after 24-48 hrs
- Start spironolactone 2mg/kg SID
- IF AF rate not started to reduce after a few hours then start digoxin
- Wean patient from i/v furosemide to oral doses twice – three times daily
Other options for treatment of CHF?
- Low salt diet
- Exercise regime
- Aspirate fluid
- Exercise:
- Within the dog’s capacity
- CONSISTENCY DAY TO DAY
- Do not allow to become exhausted
- Why are we treating dogs
- make them live longer
- make them feel better
What might be used to treat or prevent feline thromboembolic disease?
Clopidogrel
- Inhibits platelet aggregation
- No EBM as yet
- Appears relatively safe
- Mild neutropaenia in some cases
- Very bitter in taste
- 18.75mg / cat / day
Aspirin
- Inhibition of platelet aggregation
- Low dose ¼ 75mg tablet every 3 days
- No EBM to report efficacy
- Care
- Gastric ulceration
- GIT upsets
- Renal compromise
What is the name given to drugs that improve contractility?
Positive ionotropes
What is the name given to drugs that help the heart relax?
positive lusitropes
What do positive and negative chronotropes do?
Positive chronotropesincrease heart rate; negative chronotropes decrease heart rate
