heart failure

• Fluid thrill - push the abdomen with your hand and see it jiggle back like jelly
• Distended jugular vein = RHS heart failure or a mass in the cranial thorax
• fill in the blank

  A) pericardial effusion

  
• Bp is detected by baroreceptors in the aortic arch
• LHS HF = fluid build-up in the lungs
• RHS HF = fluid build-up in the abdomen
• ascites due to RHS heart failure is usually secondary to pericardial effusion or due to right sided valve disease and then often leads to a degree of left sided disease
• The typical presentation of heart disease includes…

  • Heart failure (Cough/dyspnoea)
  • Exercise intolerance
  • Collapse
  • Heart disease found by chance
  • Most murmurs are found by accident during routine check ups
  • Nonspecific malaise (discomfort) / weight loss
• In DCM there is a contractility failure so you want drugs that improve contractility (positive inotropes) such as digoxin (digitalis glycosides), pimobendan (vetmedin) and dobutamine (this has to be given via a CRI and is only used as recovery treatment)
• Digoxin is a positive inotropic agent and a negative chronotropic agent (so slows the heart), it increases vagal tone but decreases sympathetic tone while also altering baroreceptor sensitivity.

  • Predominantly renal excretion so avoid this or decrease it if the patient has renal failure

  There is a narrow therapeutic range so beware of digoxin toxicity.
• In HCM/RCM in cats the heart fills poorly so you want drugs that help the heart relax (positive lusitropes) such as calcium channel blockers (diltiazem, verapamil) and beta blockers (propanolol and atenolol)
• Therapy for CHF is traditionally based on severity and the goals of this therapy is…

  • Control Salt & Water Retention
  • Reduce Workload
  • Decrease afterload
  • Decrease physical activity and stress
  • Improve Pump Function
  • (Improve systolic function)
  • (Improve diastolic function)
  • Reverse/modify myocardial remodelling
• The treatment of CHF is the same despite the cause (e.g. DCM or chronic valvular disease). The standard therapy is a combination of drugs (triple/quad therapy) and includes…

  • Diuretics
  • Pimobendan
  • ACE Inhibitors
  • Aldosterone antagonists
  • +/- Anti-dysrhythmic medication
• when do you institute double/triple/quad therapy?

  stage C heart disease
• Furosemide and pimobendan are used at a minimum, if the owner can afford it then we use quad therapy in dogs
• QUAD therapy is SPAF

  Spironolactone

  Pimobendan

  Ace inhibitors

  Furosemide

  Triple therapy - PAF
• Diuretics remove fluid, they act at the kidney to increase urine output and hence control oedema formation.

  There are three types of diuretics…

  • Loop (powerful diuretics)
  • Furosemide
  • Torasemide
  • Potassium Sparing (weak diuretics and only used as a rescue therapy when loop diuretics aren't working as they should)
  • Spironolactone
  • Amiloride

  Diuretics cause volume depletion which can lead to potential hypovolaemia, can cause/exacerbate azotaemia and stimulate the RAAS.
• when giving furosemide be sure to monitor for azotaemia and hypokalaemia and be careful in cats with restrictive/hypertrophic diseases (can easily reduce BP too much and cause renal failure too)
• Spironolactone = is an aldosterone antagonist with a potassium sparing effect.
• These dilate arteries, veins or both

  A) venous

  B) arterial

  
• Imadipril (Prilium), Enalapril (Enacard), Benazepril (Benfortin, Nelio, Prilben, Fortekor, Kelapril) and Ramipril (Vasotop) are examples of which drug group?

  ace inhibitors
• The emergency CHF therapy includes….

  • Furosemide at 2mg/kg IV initially then 1mg/kg hourly afterwards until the respiratory rate and effort reduce (up to 4 doses in cats and more as necessary in dogs)
  • Oxygen supplementation
  • Pimobendan (IV formulation but oral therapy is preferred)
  • Cage rest
  • Avoid stress
  • Sedation as necessary (butorphanol 0.1-0.2 mg/kg)
  • Monitor renal values / electrolytes
  • Antidysrhythmic medication if necessary
• Dysrhythmias are common in patients with heart disease and will require characterisation with an ECG. Specific antidysrhythmic therapy may be required e.g. beta blocker, calcium channel blocker, digoxin