Equine murmurs Flashcards
What does the P wave represent?
Atrial contraction
What does the QRS represent?
AV valves closing
Semilunar valves open
Ventricle contracts
What does the T wave represent?
Semilunar valves close
AV valves open
Ventricles relax and fill
What ECG waves are associated with which heart sounds?
QRS: during S1
P: right before S4
T: slightly before S2
What does S4 represent?
The atrial contraction
What does S1 represent?
AV valve closure
Start of systole
What does S2 represent?
Semilunar valve closure
Start of diastole
What does S3 represent?
End of rapid ventricular filling
What are the important characteristics to note about cardiac murmurs during auscultation?
- timing (systolic-diastolic)
- duration (early, mid, late, holo, pan)
- intensity (grade 1-6)
- Shape ( crenscendo, decrescendo, band, plateau, diamond)
- Character (soft blowing, harsh, squeaking, honking, etc)
- Point of maximum intensity PMI
What is the approximate location of the pulmonic valve in the horse?
ICS3 L side
What is the approximate location of the aortic valve in the horse?
ICS 3-4 L side
What is the approximate location of the mitral valve in the horse?
ICS 5 L side
What is the approximate location of the tricuspid valve in the horse?
ICS 3-4 R side
harder to hear
What is more likely cause of murmur in foals?
PDA
What is more likely cause of murmur in welsh section A?
VSD
What is more likely cause of murmur in arabians?
congenital dz
What is more likely cause of murmur in friesans?
AoPu fistula
What is more likely cause of murmur in athletes?
AV regurgitation
What Hx can give info about murmur?
performance
collapse
weakness
epistaxis
What signs in clinical exam can give info about murmur?
dyspnea
oedema
pyrexia
synovitis
What circulatory signs can give info about murmur?
mucous membranes: pallor, cyanosis
peripheral pulses: rate and rhythm, pressure (Ao regurg, Ao fistulae)
What heart rate and rhythm signs can give info about murmurs?
resting rate: cardiac function
rhythm: brady or tachy
resting/exercise rate
What lab results can give info on mumur?
increase liver enzymes
azotemia
infl. marker
electrolytes
cardiac troponin I
Atrial natriuretic peptide
What are the normal sounds in a horse heart beat?
S1 and S2 but normal can be with S3 or S4
What does the length of a murmur indicate?
long murmur = likely diastolic
short murmur = likely systolic
Explain a late diastolic murmur?
hearing atrial contraction, pushing of blood into ventricle
physiological flow murmur
S4-S1
Explain a systolic murmur?
hearing aortic ejecting of blood, fast rushing out
common in fit horses
physiological flow murmur
right after S1
Explain a early diastolic murmur?
hearing ventricular filling
physiological flow murmur
S2-S3
What are categories of pathological murmurs?
incompetent valves
abnormal communication
stenotic valves
What are the types of systolic right heart murmurs in horses?
tricuspid regurgitation (incompetent valve)
ventricular septal defect (abnormal communication)
What are types of systolic left heart murmurs in horses?
mitral regurgitation (incompetant valves)
aortic ejection (physiological flow)
aortic/pulmonic stenosis (stenosis)
What are types of diastolic murmurs in horses?
aortic regurgitation (incompetent valve)
filling (physiological flow)
tricuspid or mitral stenosis (stenosis)
How can we differentiate Lsided systolic murmurs? aortic ejection vs mitral regurgitation
aortic ejection
- at the aortic/pulmonic valve
- early/mid-systolic
- cresc.-decresc. or decresc.
- usually grade 1-3
mitral regurgitation
- at the mitral to aortic valve
- holo/pan, mid-late systolic
- plateau or mid-late cresc.
- grade 1-6
How can we differentiate Rsided systolic murmurs? tricuspid regurg vs VSD
tricuspid regurgitation
- at tricuspid valve
- holo/pan systolic
- crescendo or band shaped
- grade 1-6, soft/blowy
VSD
- at ventral to tricuspid valve
- holo/pansystolic
- plateau/band shaped
- grade 4-6, harsh
How can we differentiate diastolic murmurs? aortic regurgitation vs filling murmur
Aortic regurg
- at the aortic valve
- holo/pan diastolic
- decrescendo, musocal
- grade 1-6
filling
- at mitral/tricuspid valve
- early or late diastolic
- musical/squak/rub
- grade 1-3
What are the clinical signs associated with murmurs in horses?
associated with effect of cardiac re-modelling or perfusion abnormalities in response to murmur and not murmur itself
poor performance
tachycardia
abnormal pulse quality, hyperkinetic
slow capillary refill time
arrhythmias
pulmonary oedema
ventral oedema
How does echocardiography help with evaluation of murmurs?
confirm site of murmur!!
identify cause of murmur (lesion)
assess severity of lesion and effect on heart
determine prognosis (suitability for ridden exercise, impact on life expectancy)
How does ECG help with evaluation of murmurs?
allows ID of concurrent arrhythmias especially during exercise
recommended in cases of aortic regurgitation
What can we see with 2D and M-mode echocardiography?
assess valve structure and function
assess chamber size
assess myocardial thickness
assess myocardial function
What can we see with doppler of echocardiography?
semi-quantative assessment of valvular regurgitations
What are causes of murmurs not assoviated with valve pathology?
functional murmurs in horses
functional/physiological valve regurgitation in horses
What are causes of murmurs associated with valve pathology?
valve degeneration (endocardiosis)
valve prolapse
rupture chordae tendineae
valve regurgitation secondary to ventricular dilation
bacterial endocarditis
What are causes of murmurs congenital abnormalities?
ventricular septal defects
persistent ductus arteriosis
valvular dysplasia
What is a haemic murmur?
without structural abnormality
hypovolaemia and/or systemic inflammation
anaemia
usually resolve once primary disease is treated
What is an early diastolic/filling murmur?
without structural abnormality
less common
short duration, high pitched squeak/whoop
after S2 before S3
PMI at heart base or AV valves
normal especially in young, training thoroughbreds
what is a functional/physiological valve regurgitation murmur?
mainly training thoroughbreds
quiet, under grade 3
not clinically significant
does not progress over time
mitral>tricuspid>aortic
What is degenerative valvular disease?
most common form of valve pathology
in horses not associated with obvious valve pathology
What is a valve prolapse murmur?
can affect any valve, causing audible murmur
mid-systolic crescendo decrescendo
may relate to the function of the valve
non-progressive regurgitation
diagnosed with echocardiography
What is a ruptures chordae tendinae murmur?
can arise spontaneously or secondary to inflammatory or degenerative changes in chordae
more common for mital valve
severe regurgitation with a rapid change in haemodynamic status
sudden death or signs of acute cardiac failure
What is a change in ventrical size murmur?
atrio-ventricular valvular regurgitation developed secondary to
- severe ventricular dilation
- cardiomyopathy and myocardial dz
- aortic regurg. and LV volume overload
mitral and/or tricuspid regurg. appear later in dz
What is bacterial endocarditis murmur?
secondary to bacteraemia
healing/scarring of valve can worsen regurgitation
large proliferative “vegetative” lesions may develop without prompt treatment
What are examples of congenital abnormal communications causing murmurs?
ventricular septal defects
atrial septal defects
atrioventricular canal defect
patent ductus arteriosus
tetralogy of fallot
What are the characteristics of tetralogy of fallot?
Pulmonary stenosis, RV outflow obstruction
RV hypertrophy
VSD
Over-riding aorta
What is the difference between R and L side VSD murmurs?
Rside: shunt L to R ventricle, harsh sound
Lside: RV overload, functional or relative pulmonic stenosis
What does the VSD murmur sound level indicate?
inversely proportional to size of defect
louder murmur = smaller hole = less blood
What are the characteristic of a R VSD murmur?
holo/pansystolic
coarse
plateau
grade 3-6
PMI tricuspid valve
What are the characteristics of a L VSD murmur?
holo/pansystolic
cresc.-decresc.
grade 3-6
PMI pulmonic valve
What is a patent ductus arteriosus?
communication between aorta and pulmonary artery in animals pre-birth
normally closes within 3 days of birth
What is a PDA murmur?
blood flows along the PDA in systole and diastole producing a continuous “washing machine” murmur
grade 3-5, wide radiation
PMI left heart base, radiates to RHS
What are examples of acquired abnormal communications causing murmurs?
aortic root rupture/ aortic-cardiac fistula
aorto-pulmonary fistula
pulmonary artery rupture
Are murmurs in horses always clinically significant?
no (functional murmur, functional valve regurg)
resting tachy always warrants further investigation
