Canine Acquire cardiovascular disease Flashcards by Maude Tanguay

What are the most common cardiac conditions in dogs?

Degenerative (acquired) mitral valve disease
Dilated cardiomyopathy
Pericardial effusion

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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

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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

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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

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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)

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What are the clinical signs of DMVD at presentation?

signs of Lsided failure
signs of collapse
sudden death (rare)
signs of Rsided heart failure

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What are the clinical findings of stage B1 and B2 DMVD?

left apical systolic murmur
+/- exercise intolerance
otherwise likely to be normal

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What are the clinical findings of stage C DMVD?

murmur higher grade
dyspnoea
tachycardia
dysrhythmia
crackles/wheezes

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What are the clinical signs of refractory/late HF DMVD?

signs of stage B and C
may progress to RCHF
ascites, jugular pulse, hepatomegaly

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What will the ECG show in DMVD?

most cases will be normal, not needed unless arrhythmia is suspected

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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

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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

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What diagnostic tool gives us definitive diagnosis of DMVD?

doppler echocardiography
demonstrates regurgitant flow, colour flow, spectral

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What is the best proven TX for DMVD prior to onset signs of CHF?

pimobendan in stage B2

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What is the best proven tx for DMVD after onset of signs of CHF?

Furosemide + pimobendan (QUEST)
also consider ACEI and spironolactone

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What is the tx regime from most important to least important once heart failure develops in DMVD?

diuretic (ex: furosemide)
pimobendan
spironolactone
ACEI

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What is bacterial endocarditis?

infection of endocardium, typically valvular

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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