Food Animal Cardiology

M. S. Gill, DVM, MS

Initial examination

Complete physical examination importantWith 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 ribs3/5’s of heart is on the left side

Examination of the heart

AuscultationHeart sounds

– S1, S2, S3, S4

Areas of auscultation of heart valvesAssessment of murmurs

Examination of the heart

S1 – beginning of ventricular systole (contracting myocardium and closure of AV valves)

S2 – closure of the semilunar valvesS3 – ventricular fillingS4 – atrial contractionNormal sequence S4 – S1 – S2 – S3

Examination of the heart

Examination of the heart

Grading murmurs– Grade I– Grade II– Grade III– Grade IV– Grade VGrade 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 cordisPatent foramen ovalePDA

Vegetative endocarditis

MurmurCHF may developArcanobacter 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 pericarditisLeukocytosis – 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 depositionPurulent exudateThickened

pericardium / epicardium

AdhesionsPossible 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 necropsyTreat 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 right heart hypertrophy,

dilatation or failure

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 endocarditisPericarditisMyocarditisCardiac lymphosarcomaDilated cardiomyopathyCor pulmonale or brisket disease

Electrocardiography

Useful for diagnosis of arrhythmiasBase-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 cattleAbsence 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 functionalMay be paroxysmal or establishedMay convert to normal sinus rhythm

spontaneouslyTreatment 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 irregularQRS complex of a PVC is premature, bizarre,

prolonged & of larger amplitudeUnifocal or multifocalTreat underlying condition or lidocaine

PVC – multifocal or multiform

PVC - unifocal

Pericarditis