Flashcards in Final Exam--Equine & Food Animal Deck (64)
Though all 4 heart sounds are considered normal to hear in the horse, which gallop sound is more common?
S4 (atrial contraction)
Contrast pathologic and physiologic(innocent) murmurs
Pathologic--backward flow through a valve that should be CLOSED
Physiologic--vibration of forward flow through a valve that should be open
How should physiologic murmurs auscultate?
short and quiet (no greater than grade 3/6)
The most common NON-PATHOLOGIC arrhythmia in horses?
second degree AV block--type 1
Describe the rhythm of second degree AV block (type 1)
regularly irregular (3 beats, pause, 3 beats, pause)
second degree AV block can be induced by?
sedatives (alpha-2 agonists)
What lead to we run horse ECGs on and why?
Lead 1--extensive purkinje network
Two most common reasons for a systolic murmur with PMI on left side (adult horses). Where does each localize?
Mitral regurgitation (MI)--APEX
Physiologic flow murmur--BASE
If you hear a murmur on the left but it's loudest on the RIGHT, what is it most likely due to?
Relative pulmonic stenosis from VSD
Two most common reasons for systolic murmurs with PMI on the RIGHT
ventricular septal defect (VSD)
Two common reasons for DIASTOLIC murmurs on the LEFT side in adult horses. Where do they localize?
Aortic regurgitation (base)
diastolic flow murmur (apex)
When it comes to VSD, you want the lesion to be _____ & have ______ _____
small; high velocity (both are GOOD prognostic factors)
4 defects associated with tetralogy of fallot
true stenosis of pulmonary valve
PMI with tetralogy of fallot is on which side and why?
LEFT side (due to right to left shunting of blood...caused by the stenosed pulmonic valve)
The most common etiology of aortic insufficiency?
Degenerative change (horses > 10yr)
A waterhammer (bounding) pulse is indicative of?
significant volume overload (due to aortic regurg)
Which valvular disease is most common in athletic/trained horses?
Most common PATHOLOGIC arrhythmia of horses?
Describe the rhythm that you hear with atrial fibrillation
irregularly, irregular (pulses are also irregular)
3 factors that can affect refractory periods in the horse?
1) high vagal tone
2) myocardial pathology
3) electrolytes disturbances (low K)
Most common complaint of owner's in horses with Afib?
A class 1a antiarrythmic used for conversion of Afib?
When should conversion for afib not be attempted?
When it is due to underlying cardiac disease/heart failure
Concerning ventricular tachycardia (VPCs)
1) HR when Tx should be considered
2) HR that indicates an emergency
How does Magnesium function in treatment of VPCs?
works as a Ca antagonist to slow conduction
Most common cause of 3rd degree AV block in horses?
scarring/fibrosis of AV node
What 3 electrolytes can impact myocyte contractility?
Ca, K, Mg
3 main causes of myocardial disease
How do ionophores cause myocyte degeneration?
bypass Na/Ca exchanger and bring Na into the cell, causing less Ca to be transported out
Ca stimulates more Ca leads from SER, causing Ca to build up in the cell and become toxic
Most common causes of CHF in horses?
Acute & chronic valvular disease
Why is alveolar edema uncommon in horses with CHF?
their lungs can handle a large amount of venous pressure before fluid enters the alveoli
Right-heart failure in horses is most commonly associated with?
Chronic left-sided disease/failure that lead to pulmonary hypertension
3 drugs that can be used for management of CHF in horses?
Location of action for:
1) Blocks Na/K ATPase
2) inhibits Na/K/2Cl symporter in thick ascending LoH
the 3 categories of vascular disease in horses
This disease of horses often occurs secondary to infection (most commonly with Step. equi)
Equine Purpura hemorrhagica
How does EPH cause vasculitis?
deposition of immune complexes in vessel (venule) walls
*Type III hypersensitivity*
Give 3 causes for:
1) increased heart sounds
2) decreased heart sounds
2) cranioventral bronchopneumonia
3) thin animal
1) displacement of heart by a mass
2) change in pericardial or pleural space
Most common pathologic arrhythmia in cattle?
In cattle, Afib commonly occurs secondary to?
an underlying GI disease (i.e. LDA, RDA)
Most common cause of pathologic murmurs in adult cattle?
valvular disease--Tricuspid insufficiency
Where to puncture for pericardiocentesis?
Left side, 5th ICS
When the heart is located outside the pleural cavity, it's called?
Where is it most commonly located instead?
The most common atrial septal defect?
patent foramen ovale
Most common valvular defect in swine?
Dysplasia of tricuspid valve
What CBC/Chem findings would support a diagnosis of hardware disease?
neutrophilic leukocytosis or leukopenia with a left shift
high fibrin, high globulins
Most common cause of acquired murmurs in cattle?
endocarditis (most common cause of valvular disease)
Most common bacteria associated with endocarditis in each spp. and preferred valve site
1) T. pyogenes; tricuspid valve (listen on R side)
2) S. suis; mitral valve (listen @ L apex)
The most common form of cardiomyopathy in livestock?
Which disease is associated with cattle kept at high altitudes?
Brisket disease (high altitude disease, mountain sickness)
List species from most to least susceptible to ionophore toxicity (list sheep, horses, and cattle)
Ionophore muscle preference in:
3) sheep & swine
1) prefers cardiac
2) cardiac and skeletal equally affected
3) mainly impacts skeletal muscle
Two factors that increase sensitivity to gossypol
1) being monogastric (i.e. swine)
2) stress (lowers tolerance)
Which part of Senna spp. are considered most hazardous? And which spp. most often develops clinical signs?
seeds (put all parts are toxic)
Grayanotoxin is associated with?
Rhododendron spp. (azaleas)
primary signs of Grayantoxin ingestion in goats?
Primary agent associated with bacterial myocarditis in cattle?
*myocarditis develops after a respiratory event (BRDC)*
2 pathogens associated with myocarditis in swine?
Erysipelothrix rhusiopathiae (chronic form)
Which type of cattle are predisposed to caudal vena cava thrombosis?
feedlot/adult cattle that are on high grain diets
A tickborne, rickettsial foreign animal disease associated with vasculitis in cattle
Predilection sites for lymphosarcoma
Heart (RA), abomasum, uterus, lymph nodes, spinal cord
4 mechanisms of heat dissipation
**only one that does NOT require temperature gradient
The gene involved with porcine stress syndrome