Food Animal Cardiology

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Food Animal Cardiology

• M. S. Gill, DVM, MS

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Initial examination

• Complete physical examination important
• With special attention given to
• Mucous membrane color
• Presence of jugular pulses
• Edema

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Jugular pulse
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Jugular pulse edema
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Examination of the heart

• Heart occupies ventral position in the thorax
• Between the 3rd and 6th ribs
• 3/5s of heart is on the left side

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Examination of the heart

• Auscultation
• Heart sounds
• S1, S2, S3, S4
• Areas of auscultation of heart valves
• Assessment of murmurs

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Examination of the heart

• S1 beginning of ventricular systole
  (contracting myocardium and closure of AV valves)
• S2 closure of the semilunar valves
• S3 ventricular filling
• S4 atrial contraction
• Normal sequence S4 S1 S2 S3

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Examination of the heart
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Examination of the heart

• Grading murmurs
• Grade I
• Grade II
• Grade III
• Grade IV
• Grade V
• Grade I is not clinically significant.
• Grades IV and V are usually significant

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Evaluation of the heart

• Heart rate should equal pulse
• Tachycardia
• Bradycardia
• Rhythm
• Most common arrhythmia in cattle is atrial
  fibrillation

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Congenital cardiac defects

• Early detection important
• Expense
• Genetic implications

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Congenital cardiac defects

• Ventricular septal defect
• Left to right shunt
• Tetralogy of Fallot
• Right to left shunt, cyanosis
• Ectopia cordis
• Patent foramen ovale
• PDA

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Vegetative endocarditis

• Murmur
• CHF may develop
• Arcanobacter pyogenes or a-hemolytic strep in
  cattle, erysipelothrix or strep in swine
• Lesions on valves are usually embolic in origin
• Right AV valve usually affected

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Vegetative endocarditis

• Clinical signs
• Poor doing animal
• Exercise intolerance
• CHF
• Fluctuating fever
• Clinical pathology
• Severe leukocytosis
• Diagnostics
• Blood cultures
• Echocardiography

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Vegetative endocarditis

• Large cauliflower-like or small verrucous lesions
  on heart valves, or,
• Shrunken, scarred heart valves

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Vegetative endocarditis
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Vegetative endocarditis

• Treatment
• Cephalosporins/penicillin to calves with
  omphalophlebitis
• Long term, broad spectrum antibiotics to cattle
  with vegetative endocarditis
• Prognosis poor

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Pericarditis

• Inflammation of the visceral and parietal
  pericardium
• Most likely due to traumatic pericarditis
  extension of traumatic reticuloperitonitis

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Pericarditis

• Pathophysiology
• Penetration of pericardium by metallic foreign
  body fibrinous exudate effusion
  with splashing sounds compromised heart
  function CHF

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Pericarditis

• Clinical signs
• Pain
• Kyphosis
• Abduction of elbows
• Shallow respirations
• T 103-106º F
• Fluid splashing cardiac sounds or friction rubs
  or muffled heart sounds
• CHF may develop late in the course

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Pericarditis

• Most cows with pericarditis die in 1-3 weeks
• Some develop chronic pericarditis
• Leukocytosis 16,000-30,000 WBC

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Pericarditis

• Pericardiocentesis
• Centesis performed at the 4th or 5th intercostal
  space at the level of the elbow on the left side

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Pericarditis
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Pericarditis

• Fibrin deposition
• Purulent exudate
• Thickened pericardium / epicardium
• Adhesions
• Possible presence of metallic foreign body

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Pericarditis

• Treatment
• Not very successful
• Long term, broad spectrum antibiotics
• 5th or 6th rib resection (pericardiotomy) may be
  attempted but not very successful

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Myocardial disease

• Myocarditis
• Inflammation of the myocardial wall (bacterial,
  viral, parasitic)
• Cardiomyopathy
• Dilated cardiomyopathy is the only form of
  clinical significance in large animals

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Myocarditis

• Bacterial
• Staph, Clostridium, 2º to bacteremia or
  septicemia, pericarditis, endocarditis
• Viral
• FMD
• Parasitic
• Toxoplasmosis, cysticercosis, sarcocystis

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Myocarditis

• May be incidental finding at necropsy
• Treat primary condition i.e., cow with mastitis

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Cardiomyopathy

• Toxicities
• Monensin, lasalocid
• Gossypol
• Cassia
• Phalaris
• Deficiencies
• Vitamin E/Se (WMD or nutritional myodegeneration)
• Copper deficiency

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Cardiomyopathy

• Other causes
• Excess molybdenum
• High sulfates
• Lymphosarcoma neoplastic infiltration of
  myocardium

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Cardiomyopathy

• Clinical signs usually present with CHF
• Treatment poor prognosis treat CHF

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Cor pulmonale

• Pulmonary hypertension, brisket disease, high
  altitude disease, or high mountain disease
• Cor pulmonale reflects effect of lung dysfunction
  on heart, therefore, heart disease is secondary

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Cor pulmonale

• Pathophysiology
• Pulmonary hypertension right heart
  hypertrophy, dilatation or failure
• Underlying cause is hypoxic vasoconstriction
  caused by
• High altitude dwelling (gt 6,000 feet)
• Pulmonary disease (bronchopneumonia or lungworms)
  

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Cor pulmonale

• Clinical signs
• Signs of CHF
• Treatment
• Remove from high altitude
• Treat any primary lung disease
• Reversible if treated early

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Differentials for CHF

• Vegetative endocarditis
• Pericarditis
• Myocarditis
• Cardiac lymphosarcoma
• Dilated cardiomyopathy
• Cor pulmonale or brisket disease

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Electrocardiography

• Useful for diagnosis of arrhythmias
• Base-apex lead
• Normal ECG
• Small positive P wave (may be notched)
• QRS complex is either rS or QS
• T is a positive monophasic or negative/positive
  biphasic wave

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Normal cattle ECG
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Atrial fibrillation

• Most common arrhythmia in cattle
• Absence of P waves, presence of f waves,
  ventricular tachycardia with irregular rhythm
• Atria remain distended quiver due to numerous
  independent fronts of depolarization
• CHF unlikely

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Atrial fibrillation

• Organic underlying heart disease
• Functional - 2º to other abnormalities
• GI disturbances, electrolyte abnormalities,
  pulmonary disease, brain disease

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Atrial fibrillation

• Most cases are functional
• May be paroxysmal or established
• May convert to normal sinus rhythm spontaneously
• Treatment involves correcting underlying
  condition quinidine has been used in some cases
  that dont correct on own

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Atrial fibrillation
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Atrial fibrillation
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Sinus arrhythmia
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Premature ventricular contractions

• Etiology
• Primary myocardial disease
• Secondary to increased sympathetic tone, hypoxia,
  anemia, uremia, acidosis, sepsis, hypokalemia or
  various drugs
• Rate normal but rhythm irregular
• QRS complex of a PVC is premature, bizarre,
  prolonged of larger amplitude
• Unifocal or multifocal
• Treat underlying condition or lidocaine

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PVC multifocal or multiform
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PVC - unifocal
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Pericarditis