Equine Heart Murmurs Flashcards
Single cardiac murmur:
How is valvular insufficiency/regurgitation localized? What are clinical signs like?
auscultation
VARIABLE
- slight = no consequence
- consequences if arrhythmias or other heart changes
What valvular insufficiencies/regurgitations have the most impact on performance?
mitral > aortic > tricuspid > pulmonary
What is the diagnostic approach to valvular insufficiencies/regurgitations?
- auscultation
- echocardiography at rest and exercise to confirm, evaluate severity, and assess consequences
- ECG at rest and exercise
What 2 things are mitral valve regurgitations likely to do?
- have an impact on performance
- evolve and cause heart failure
What is the etiology of mitral valve regurgitation? What are the 2 consequences?
degenerative process leads to dilation of the mitral ring, spontaneous chordal rupture, and eventual endocarditis
- MILD: tolerated with minimal compromise
- SEVERE: exercise intolerance, heart failure
What is most commonly heard on auscultation in patients with mitral valve regurgitation?
holo/pan systolic murmur, grade 2-5
What clinical signs are associated with mitral valve regurgitation?
- none if mild
- exercise intolerance
- increased respiratory rate and effort at rest
- prolonged recovery after exercise
- coughing
What short-term, acute, and long-term signs are associated with mitral valve regurgitation?
SHORT-TERM = left heart failure
ACUTE = fulminant pulmonary edema, collapse
LONG-TERM = evolves to right heart failure
How is mitral valve regurgitation diagnosed?
echocardiography and Doppler show blood leaking into LA (flail leaflet)
- valve anatomy + size of atria, ventricles, and vessels
- severity of regurgitation
- LV systolic function
- degeneration, prolapse, endocarditis
What 4 things does the severity of valvular regurgitation depend on?
- age
- clinical signs
- rapidity of onset
- performance level
When is prognosis good in patients with valvular regurgitation?
- no clinical signs or exercise intolerance
- mild insufficiency
- no functional or morphologic repercussion
What 4 things cause prognosis to be guarded in patients with mitral valve regurgitation?
- clinical signs, moderate to severe insufficiency
- ruptured chordae tendinae, endocarditis
- globular apex, LA dilation = risk of AF
- pulmonary hypertension = risk of pulmonary edema
In what horses is aortic valve regurgitation most common? What is felt on pulse palpation?
older (>10 y/o) - severity not proportional to intensity
bounding, water hammer pulse indicative of ventricular enlargement (decreases prognosis)
What is the etiology of aortic valve regurgitation? What does consequences depend on?
degenerative process
severity and presence of arrhythmias (do an ECG!)
What is heard on auscultation in patients with aortic valve regurgitation?
holo diastolic, muscial, decresendo murmur
(between S2 and S1)
How is aortic valve regurgitation diagnosed?
echocardiography and Doppler show a thickened aortic valve (endocarditis) and backward flow back into the LV
What is the most common finding on ECG in patients with aortic valve regurgitation?
VPC arrhythmia
- no P wave!
What 7 things cause prognosis to be guarded in patients with aortic valve regurgitation?
- moderate to severe with clinical signs
- left ventricular dilation
- globular apex
- septal hyperkinesia
- mitral insufficiency
- dilated aorta
- arryhthmias
In what horses is tricuspid valve regurgitation common? What increases the intensity?
athletic horses
training
What is the etiology of tricuspid valve regurgitation? What consequence is most common?
training and degeneration
uncommon —> cor pulmonale (secondary to pulmonary issues)
What is heard of auscultation in patients with tricuspid valve regurgitation?
holo systolic murmur audible on the right side, between S1 and S2
(check jugular pulse!)
How is tricuspid valve regurgitation diagnosis? What is prognosis like?
echocardiography and Doppler
good —> regular rechecks if moderate to severe
What is infective endocarditis? What are the 3 most common causes?
invasion of the heart valves by bacteria
- Strep
- A. equuli
- Rhodococcus
What is the pathophysiology of infective endocarditis? What valves are most commonly affected?
bacterial injury leads to exposure of valve collagen, which increases risk of thrombosis + leukocyte response = vegetation
- aortic
- mitral
- tricuspid (thrombophlebitis)
What are the most common clinical signs associated with infective endocarditis? What concurrent diseases are most common? What is heard on auscultation?
- intermittent fever
- weight loss
- depression
- anorexia
- intermittent lameness due to synovial distension
thromboplebitis, abscess (Strangles, Rhodococcus)
murmur corresponding to affected valve
How is infective endocarditis diagnosed?
- blood work: anemia, inflammatory changes (neutrophilia)
- blood culture (fever)
- echocardiography: thickened and shaggy valves
How is infective endocarditis treated? Prognosis?
- aggressive, long-term antibiotics
- NSAIDs
- Heparin
expectation for long-term survival is poor
When should congenital heart defects be suspected?
- young patient
- holo/pan systolic/diastolic murmur
- continuous murmur
- thrill or wide radiation
(longer murmurs)
In what 3 situations is cyanosis present with congenital heart defects?
- right to left shunt
- obstructive pulmonary disease
- severe stenosis of right heart structures
What is the most common cardiac malformation in horses?
ventricular septal defect (VSD) - an opening in the interventricular septum caused by developmental issues
What are the 3 most common consequences of ventricular septal defect (VSD)?
- shunt L > R if there are no other CV lesions
- increased pulmonary blood flow and pulmonary venous return increases the load in left heart
- shunt may reverse over time
What do clinical signs of ventricular depend on? What clinical signs are most common?
size, direction/location/number of shunts, and concurrent disease
- poor performance and growth
- lethargy
- heart failure
What 3 things are typically heard on auscultation in patients with ventricular septal defects? How does intensity relate to severity?
- loud, harse, plateau murmur with PMI below tricuspid
- thrill
- relative pulmonary stenosis murmur
intensity of murmur NOT associated with severity
How is ventricular septal defects diagnosed?
- history
- PE
- auscultation
- echocardiography: shunt size, velocity, location, direction
What is a patent ductus arteriosus (PDA)?
fetal vessel that shunts from pulmoary artery to the descending aorta and constructs at birth remains intact
How should the ductus arteriosus act after birth of a foal?
constricts at birth due to increased blood oxygen and decreased prostaglandins and becomes functionally closed in foals after 72-96 hrs
What do clinical signs of patent ductus arteriosus depend on?
- length, diameter, and direction of the vessel
- presence of other abnormalities
What 2 things are most commonly heard on auscultation in patients with patent ductus arteriosus? When is this commonly heard and not a problem?
- continuous machinery murmur + thrill craniodorsal to the aorta
- heard on both L and R side, loudest in the left 3rd-4th ICS
foals in the first days of life —> persistent PDA is rare
What is the tetralogy (pentalogy) of Fallot?
- overriding aorta
- VSD
- obstruction of the pulmonary arterial flow
- secondary right ventricular hypertrophy
(5.) atrial septal defect
What are the most common clinical signs seen in tetralogy (pentalogy) of Fallot?
- cyanosis (rare at rest)*
- marked exercise intolerance, dyspnea, collapse
- slow growth, small size
- loud pan systolic murmur and thrill
A systolic murmur best heard on the right side is likely…
a. mitral valve regurgitation
b. pulmonic valve regurgitation
c. tricuspid valve regurgitation
d. aortic valve regurgitation
C
What are the most common sites for endocarditis?
a. tricuspid and pulmonic valve
b. aortic and mitral valve
c. aortic and pulmonary valve
d. mitral and tricuspid valve
B —> left heart
Rupture of the mitral valve leads to which of the following issues?
a. peripheral edema
b. pulmonary edema
B —> left-sided heart failure
Aortic regurgitation is most frequent in what type of horse?
a. older horses
b. race horses
c. young horses
d. large horses
A
- tricuspid = athletes
- mitral = affects performance
How would you describe this murmur?
diastolic plateau