Canine Acquire cardiovascular disease Flashcards
What are the most common cardiac conditions in dogs?
Degenerative (acquired) mitral valve disease
Dilated cardiomyopathy
Pericardial effusion
What is the pathophysiology of DMVD?
distortion of valve leaflets due to degenerative change
results in development of insufficiency
= needs an increase of ventricular stroke volume
leads to ventricular dilatation
exacerbates leakage of valve
worsened by vasocontriction
What age, breed and sex is most likely to get mitral valve dz?
typically older dogs (7+)
small breed dogs (CKCS, terriers, Poodles, Dachsund, Chihuahua)
Affects males earlier in certain breeds
What age breed and sex is most likely to get dilated cardiomyopathy?
middle aged to older dogs
large breed dogs (doberman, great dane, IWH, boxers)
may affect males more in certain breeds
What are the stages of MVD?
Stage A: predisposed to get dz
Stage B1: preclinical normal heart size (small leak, no compensation needed)
Stage B2: preclinical cardiomegaly (enlarged heart is first compensation)
Stage C: CHF (decompensates)
What are the clinical signs of DMVD at presentation?
signs of Lsided failure
signs of collapse
sudden death (rare)
signs of Rsided heart failure
What are the clinical findings of stage B1 and B2 DMVD?
left apical systolic murmur
+/- exercise intolerance
otherwise likely to be normal
What are the clinical findings of stage C DMVD?
murmur higher grade
dyspnoea
tachycardia
dysrhythmia
crackles/wheezes
What are the clinical signs of refractory/late HF DMVD?
signs of stage B and C
may progress to RCHF
ascites, jugular pulse, hepatomegaly
What will the ECG show in DMVD?
most cases will be normal, not needed unless arrhythmia is suspected
What are the radiographic changes that can be seen with DMVD?
We mostly see signs of heart failure and we are looking for any signs of enlargement
LA enlargement
LV enlargement
Bronchial compression
Pulmonary venous congestion
pulmonary oedema
RCHF signs
What are the echocardiography changes that can be seen with DMVD?
Valvular changes: rough irregular leaflets, prolapse, ruptured chordae, failure of apposition
Chamber enlargement: LAE, LV dilatation
Myocardial function: alteration of fractional shortening
What diagnostic tool gives us definitive diagnosis of DMVD?
doppler echocardiography
demonstrates regurgitant flow, colour flow, spectral
What is the best proven TX for DMVD prior to onset signs of CHF?
pimobendan in stage B2
What is the best proven tx for DMVD after onset of signs of CHF?
Furosemide + pimobendan (QUEST)
also consider ACEI and spironolactone
What is the tx regime from most important to least important once heart failure develops in DMVD?
diuretic (ex: furosemide)
pimobendan
spironolactone
ACEI
What is bacterial endocarditis?
infection of endocardium, typically valvular
What are the clinical signs of bact. endocarditis?
pyrexia of unknown origin
lameness
sepsis
What is the tx and prognosis for bacterial endocarditis?
tx: appropriate antibiotic tx over many weeks + management of any other signs
prognosis: guarded
What are the 5 types of cardiomyopathies?
Dilated
Hypertrophic
Restrictive
Arrhythmogenic RV
Intermediate/unclassified
What is dilated cardiomyopathy?
systolic failure of the myocardium
dilatation of the ventricle due to increased end diastolic pressures
can lead to valvular insufficiency secondary to dilatation
What are the clinical signs of DCM?
can be incidental/ “occult”
can have signs of forward or backward failure
What are the signs of forward failure?
intermittent collapse
weakness
sudden death
What are the signs of backwards failure?
cough
exercise intolerance
dyspnoea
ascites
What are the PE findings in DCM cases?
systolic murmur
gallop rhythm
arrhythmia, pulse deficits
signs of CHF (dyspnoea, crackles, cough, ascites, pleural effusion, S/C oedema)
What are the possible ECG findings in cases with DCM?
sinus tachy
Atrial premature complex
a fib
VPC
Paroxysmal v tach
What radiographic findings can be supportive of the DCM diagnosis?
can’t be diagnostic but can support
evidence of cardiomegaly
evidence of congestive heart failure
RCHF
What are the findings on echocardiohraphy for DCM?
dilatation and systolic function are key features
dilated hypokinetic LV
fractional shortening
increased LVID-D and LVID-S
may also see LAE, mitral insufficiency
What are indices of systolic function?
fractional shortening
ejection fraction
systolic time intervals
doppler tissue imaging
What is the best proven tx for DCM prior to onset of signs of CHF?
Pimobendan prior to onset of signs delays onset and prolongs survival
possible benefit of ACEI
What is the best proven tx for DCM after onset of signs of CHF?
furosemide, ACEI and pimobendan
consider spironolactone
When the best proven tx are exhausted, what other steps can help manage cardiac dz?
optimise rate and rhythm (controling rate in AF or severity of rhythm disturbance in vtach)
antagonise neurohormonal mechanisms (ACEI, B-blockers, spironolactone)
Nutritional support
What is pericardial effusion and what are the main causes?
common acquired cause of Rsided heart failure in the dog
causes: idiopathic pericarditis, neoplasia, etc
What is the pathophysiology of pericardial effusion?
Increase in pressure within pericardial sac -> compromises the diastolic function
R side more affected since RV is thin walled
causes RSCHF
if acute in onset, may see signs of syncope and forward failure
What signs will be in the hx of pericardial effusion?
typically acute onset
lethargy
RCHF: ascites, dyspnoea
possible collapse
possible hx of coughing
What clinical signs will be seen in PE with pericardial effusion?
signs of RCHF
Signs due to fluid around the heart: muffled heart sounds, pulsus paradoxus
What is pulsus paradoxus?
decreasing femoral pulse strength on inspiration
What can be seen on an ECG in a pericardial effusion patient?
usually not very helpful
small QRS complexes, electrical alternans
What can be seen on a radiograph in pericardial effusion patient?
generalised enlargement of the cardiac silhouette
clear outline of silhouette
signs of RCHF: ascites, pleural effusion
What can be seen on an ultrasound in pericardial effusion patient?
presence of fluid
could indicate cause of effusion
may show evidence of cardiac tamponade (collapse of RA and RV duirng diastole)
may help indicate the best site to carry out pericardiocentesis
What is the tx for pericardial effusion?
only effective tx is removal of fluid from pericardial sac\drug therapy contraindicated due to limited CO and compromised diastolic function
aka: pericardiocentesis
How do we perform a pericardiocentesis?
drainage of fluid from pericardium leads to rapid relief of clinical symptoms
level of costochondral junction RHS thorax ribspace 5 or 6, can use ultrasound guidance
ECG monitor throughout
loacl anaesthetic in skin, intercostal muscles and down to pleura
aseptic preparation of site
14G catheter with closed drainage site
collect for cytology, culture, pH and protein
What is the prognosis for pericardial effusion?
dependent on underlying disease
idiopathic: may be cured by drainage but tends to reoccur
neoplastic: generally poor, particularly with RA haemangiosarcoma
chemodectomas slow growing
FB or infectious may be manageabke with surgery
