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

Myocarditis Bacterial Viral Parasitic 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: Deficiencies 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 Treatment Signs of CHF 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