Management of heart failure

Cards (11)

  • Typical presentation of heart disease
    Heart failure - cough/ dyspnoea
    Exercise intolerance
    Collapse
    Heart disease found by chance
    Non-specific malaise/ weight loss.
  • Non-specific treatment of dilated cardiomyopathy
    DCM is due to contractility failure.
    Use drugs that improve contractility = positive inotropes
    Digoxin (digitalis glycosides)
    Pimobendan (Vetmedin)
    Dobutamine
    Dobutamine has to be given in an IV infusion, constant rate so used more as a recovery treatment for dogs with DCM.
    Pimobendan is used the most, is a positive isotope and vasodilates as well.
  • Pimobendan
    Positive isotope. Gold standard.
    Inodilator - decreased systemic/ pulmonary vascular resistance.
    Calcium-sensitising drug (positive inotrope)
    PDE III inhibitors - vasodilation.
    Antithrombotic activity - can be useful in cats.
  • Digoxin
    Positive inotropic agent. Negative chronotropic agent. Increased vagal tone, decreases sympathetic tone. Alters baroreceptor sensitivity. Predominatly renal excretion - avoid drug or decrease dose in renal failure. Narrow therapuetic range - digoxin toxicity.
    Slows down the heart, useful in animals with heart failure die to cardiomyopathy and tachycardia.
  • Non-specific treatment of Hypertrophic/Restrictive cardiomyopathy
    Heart fills poorly. Use drugs that help relax = positive lusitropes.
    Calcium channel blockers - diltiazem, verapamil
    Beta blockers - propranolol, atenolol.
    In asymptomatic cats there is no evidence that any drugs alters the natural history of HCM until they are in heart failure.
    These are diseases of diastole, so need the heart to relax more, only treat when they have signs.
  • Diltiazem
    Licensed product, have positive lusitropic properties. May reduce left ventricular hypertrophy.
    Doesn’t have much clinical effect on survival time in cats with severe HCM and HF.
  • General treatment of Congestive heart failure
    The therapy for CHF is traditionally based on severity.
    The goal;
    Control salt and water retention.
    Reduced workload
    Decreased afterload
    Decrease physical activity and stress
    Improve pump function
    Improve systolic function
    Improve diastolic function
    Reverse/ modify myocardial remodelling.
  • Standard congestive heart failure therapy
    Combination of drugs; triple/quad therapy
    Diuretics (remove salt water)
    Pimobendan (vasodilator)
    ACE inhibitors
    Aldosterone antagonists
    +/- Anti-dysrhythmic medication
  • Diuretics
    Remove fluid - diuretic traditionally used (act at kidney to increase urine output).
    Control oedema formation.
    Oedema in CHF is usually due to increase in circulating blood volume.
    Blood volume can be increased by as much as 30% in severe CHF.
    Loop diuretics
    Furosemide - cheap
    Torasemide - used more as has a longer half life so only have to give it once a day.
    Potassium and Thiazide are not very strong diuretics, tend to be used if the loop diuretics are not strong enough by themselves.
  • Furosemide
    1st line diuretic, very potent. Plasma half time is 15 minutes, peak effect orally is 1-2 hours, duration of action is 4-5 hours. More potent when given parentally. Works on the loop of Henle to limit sodium absorption.
    Frequently tailored to individual - severity of volume and oedema. Can be high doses in some cases, reduce dose as soon as possible. Monitor animal for azotaemia and hypokalaemia.
  • Spironolactone
    Aldosterone antagonist has a potassium sparing effect. Beneficial effects in CHF leads to an improvement in cough, dyspnoea, syncope, mobility.