Congestive Heart Failure (CHF)

Congestive Heart Failure (CHF)

Congestive heart failure (CHF) is a complex clinical condition characterized by inefficient myocardial contractions, resulting in compromised blood supply to the body and development of congestion.

Etiology

  • Valvular disease like Endocarditis, Congenital valvular defects or Rupture of valve or valve chordae.
  • Myocardial diseases like Myocarditis, Myocardial degeneration, Congenital or hereditary cardiomyopathy or Toxins affecting cardiac conduction.
  • Congenital anatomical defects producing shunts.
  • Hypertension
  • Pressure load
  • Volume load
  • Pumping defects (systolic failure)
  • Filling defects (diastolic failure)

Pathogenesis

Congestive heart failure (CHF) may be right sided or left sided. According to this pathogenesis also varies.

Right sided congestive heart failure (CHF)
Right sided congestive heart failure (CHF)
Left sided congestive heart failure (CHF)
Left sided congestive heart failure (CHF)

Clinical Findings

  • Respiratory distress on light exertion
  • Tachycardia
  • Loss of body weight

Clinical findings in left-sided CHF:

  • Tachycardia
  • Increase in rate & depth of respiration at rest
  • Cough
  • Presence of crackles (discontinuous sounds) at the base of the lungs
  • Increased dullness on percussion of the ventral borders of the lungs
  • Severe dyspnea and cyanosis

Clinical findings in right-sided CHF:

  • Engorgement of superficial veins
  • Subcutaneous edema
  • Ascites
  • Hepatomegaly
  • Epistaxis and exercise intolerance esp. horse, dogs

Diagnosis

  • Examination of fluid effusion
  • Edematous transudate except in pericardial tamponade (serosanguinous) or pericarditis (effusion). it may be septic or non-septic.
  • Protein in urine
  • Cardiac troponin I provides an excellent cardiac biomarker in large animals

Necropsy Findings

  • Left-sided CHF: Pulmonary congestion and edema
  • Right-sided CHF: Anasarca, ascites, hydrothorax and hydropericardium Enlargement or engorgement of liver, with ‘nutmeg’ appearance.

Prognosis

  • Poor to Grave
  • Animal survive with a permanently reduced cardiac reserve

Treatment

  • Pericarditis or pericardial tamponade to removing the pericardial fluid and preventing its return.
  • Reducing effects of increased preload by administering diuretic agents (like frusemide) and restricting sodium intake.
  • Advise rest
  • Oxygen supplementation
  • Reduction of pulmonary venous pressure with IV frusemide 2-8 mg/kg in severe pulmonary edema then reduced to 2-4 mg/kg every 8-12 hours
  • Vasodilator like sodium nitroprusside
  • Sympathomimetics (Dobutamine 5-15 µg/kg/min in 5% dextrose and Dopamine 1-2 µg/kg/min)
  • ACE inhibitors like Enalapril (0.5 mg/kg PO BID), Benazepril (0.25-0.5 mg/kg/day PO)
  • Positive inotropes like Digoxin(0.003-0.005 mg/kg initially)
  • Pimobendan (0.2-0.3mg/kg PO BID
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