Download Food Animal Cardiology

Food Animal Cardiology
M. S. Gill, DVM, MS
Initial examination
Complete physical examination important
With special attention given to:
– Mucous membrane color
– Presence of jugular pulses
– Edema
Jugular pulse
Jugular pulse & edema
Examination of the heart
Heart occupies ventral position in the
thorax
Between the 3rd and 6th ribs
 3/5’s of heart is on the left side
Examination of the heart
Auscultation
Heart sounds
– S1, S2, S3, S4
Areas of auscultation of heart valves
Assessment of murmurs
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
Examination of the heart
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
Evaluation of the heart
Heart rate – should equal pulse
– Tachycardia
– Bradycardia
Rhythm
– Most common arrhythmia in cattle is atrial
fibrillation
Congenital cardiac defects
Early detection important
– Expense
– Genetic implications
Congenital cardiac defects
Ventricular septal defect*
– Left to right shunt
Tetralogy of Fallot
– Right to left shunt, cyanosis
Ectopia cordis
Patent foramen ovale
PDA
Vegetative endocarditis
Murmur
CHF may develop
Arcanobacter pyogenes or α-hemolytic
strep in cattle, erysipelothrix or strep in
swine
Lesions on valves are usually embolic in
origin
Right AV valve usually affected
Vegetative endocarditis
 Clinical signs
–
–
–
–
Poor doing animal
Exercise intolerance
CHF
Fluctuating fever
 Clinical pathology
– Severe leukocytosis
 Diagnostics
– Blood cultures
– Echocardiography
Vegetative endocarditis
 Large cauliflower-like
or small verrucous
lesions on heart
valves, or,
 Shrunken, scarred
heart valves
Vegetative endocarditis
Vegetative endocarditis
Treatment
– Cephalosporins/penicillin to calves with
omphalophlebitis
– Long term, broad spectrum antibiotics to cattle
with vegetative endocarditis
– Prognosis poor
Pericarditis
Inflammation of the visceral and parietal
pericardium
Most likely due to traumatic pericarditis –
extension of traumatic reticuloperitonitis
Pericarditis
Pathophysiology
– Penetration of pericardium by metallic foreign
body
fibrinous exudate
effusion with
splashing sounds
compromised heart
function
CHF
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
Pericarditis
Most cows with pericarditis die in 1-3
weeks
Some develop chronic pericarditis
Leukocytosis – 16,000-30,000 WBC
Pericarditis
Pericardiocentesis
– Centesis performed at the 4th or 5th intercostal
space at the level of the elbow on the left side
Pericarditis
Pericarditis
 Fibrin deposition
 Purulent exudate
 Thickened
pericardium /
epicardium
 Adhesions
 Possible presence of
metallic foreign body
Pericarditis
Treatment
– Not very successful
– Long term, broad spectrum antibiotics
– 5th or 6th rib resection (pericardiotomy) may be
attempted but not very successful
Myocardial disease
Myocarditis
– Inflammation of the myocardial wall
(bacterial, viral, parasitic)
Cardiomyopathy
– Dilated cardiomyopathy is the only form of
clinical significance in large animals
Myocarditis
Bacterial
– Staph, Clostridium, 2º to bacteremia or
septicemia, pericarditis, endocarditis
Viral
– FMD
Parasitic
– Toxoplasmosis, cysticercosis, sarcocystis
Myocarditis
May be incidental finding at necropsy
Treat primary condition – i.e., cow with
mastitis
Cardiomyopathy
 Toxicities:
–
–
–
–
Monensin, lasalocid
Gossypol
Cassia
Phalaris
 Deficiencies
– Vitamin E/Se (WMD or nutritional myodegeneration)
– Copper deficiency
Cardiomyopathy
Other causes
– Excess molybdenum
– High sulfates
– Lymphosarcoma – neoplastic infiltration of
myocardium
Cardiomyopathy
Clinical signs – usually present with CHF
Treatment – poor prognosis – treat CHF
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
Cor pulmonale
 Pathophysiology:
– Pulmonary hypertension
dilatation or failure
right heart hypertrophy,
 Underlying cause is hypoxic vasoconstriction
caused by
– High altitude dwelling (> 6,000 feet)
– Pulmonary disease (bronchopneumonia or
lungworms)
Cor pulmonale
Clinical signs
– Signs of CHF
Treatment
– Remove from high altitude
– Treat any primary lung disease
– Reversible if treated early
Differentials for CHF
Vegetative endocarditis
Pericarditis
Myocarditis
Cardiac lymphosarcoma
Dilated cardiomyopathy
Cor pulmonale or brisket disease
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
Normal cattle ECG
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
Atrial fibrillation
Organic – underlying heart disease
Functional - 2º to other abnormalities
– GI disturbances, electrolyte abnormalities,
pulmonary disease, brain disease
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 don’t correct on own
Atrial fibrillation
Atrial fibrillation
Sinus arrhythmia
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
PVC – multifocal or multiform
PVC - unifocal
Pericarditis