Acquired cardiovascular disease in dogs Flashcards
most common diseases
Degenerative (acquired) mitral valve disease Endocardiosis Myxomatous valve disease Dilated cardiomyopathy Pericardial effusion Neoplastic Idiopathic
degenerative mitral valve disease (DMVD) - pathophysiology
Distortion of valve leaflets due to degenerative change.
Results in development of insufficiency
Necessitates an increase in the ventricular stroke volume
Leads to ventricular dilatation
Exacerbates leakage of valve
Worsened by vasoconstriction
DMVD - history
older dogs
smaller breeds
affects males earlier
DMVD - clinical signs
often incidental finding
Signs of left sided failure - Cough, Dyspnoea, Exercise intolerance
Signs of collapse - Dysrhythmias
Sudden death (rare) - Arrhythmia/left atrial tear/Ruptured chord
Signs of right sided heart failure -Late in disease progression
DMVD - Diagnostic evaluation
Clinical examination E.C.G. Radiography Echocardiography Blood tests
DMVD - clinical exam
mild - compensated, Left apical systolic murmur, +/- exercise intolerance may be otherwise normal.
moderate - developing failure, Murmur higher grade, Dyspnoea, Tachycardia, Dysrhythmia, Crackles/Wheezes
severe - overt CHF, above present + may progress to RCHF, Ascites, Jugular pulses, hepatomegaly
DMVD - electrocardiogram
usually normal
may see hypertrophy pattern
rarely rhythm disturbance
DMVD - radiography
Variable changes possible as disease progresses
Left atrial enlargement, lateral and DV views
Left ventricular enlargement
Bronchial compression
Pulmonary venous congestion
Pulmonary oedema
RCHF signs -Pleural effusion, Ascites, Hepatomegaly
DMVD - echocardiography
Valvular changes -Rough irregular leaflets, Prolapse, ruptured chordae, Failure of apposition
Chamber enlargement - L.A.E., L.V. dilatation (diastole)
Myocardial function - Alteration of fractional shortening
DMVD - definitive diagnosis
Doppler echocardiography
Demonstrate regurgitant flow
Colour flow
Spectral
DMVD - treatment regime - heart failure
Diuretic
Pimobendan
ACE inhibitor
Spironolactone
pimobendan
calcium sensitizer with positive inotropic and vasodilator effects
selective inhibitor of phosphodiesterase III (PDE3)
smaller cardiac preload and afterload
bacterial endocarditis
Rare disease
Infection of Endocardium, typically valvular
bacterial endocarditis - clinical signs
Pyrexia of unknown origin
Lameness
Sepsis
bacterial endocarditis - diagnosis
Echocardiography, Blood cultures, changing murmur
bacterial endocarditis - treatment
Appropriate antibiotic therapy over many weeks
bacterial endocarditis - prognosis
guarded
types of cardiomyopathy
dilated (common) hypertrophic (v.rare in dogs) restrictive Arrhythmogenic right ventricular cardiomyopathy Intermediate/Unclassified
dilated cardiomyopathy
Systolic failure of myocardium
Dilatation of the ventricle due to increased end diastolic pressures
May lead to valvular insufficiency secondary to dilatation.
Aetiology unclear
dilated cardiomyopathy - clinical signs
may be incidental finding
forward and/or backward failure
Forward failure -intermittent collapse, weakness, sudden death
Backward failure -cough, exercise intolerance, dyspnoea, ascites
dilated cardiomyopathy - physical exam
Findings variable
Systolic murmur (likely to be softer than DMVD)
Gallop rhythm
Arrhythmia, pulse deficits (more likely that in DMVD)
Signs of CHF
dilated cardiomyopathy - ECG
Variety of rhythm disturbances can occur Sinus tachycardia A.P.C.’s A.F. V.P.C.’s Paroxysmal V. Tach
dilated cardiomyopathy - radiography
findings supportive but not diagnostic
Evidence of cardiomegaly - Generalised, LVH, LAE
Evidence of congestive failure - LCHF, Pulmonary oedema + congestion
RCHF - Ascites, Pleural effusion
dilated cardiomyopathy - echo
Two key features: Dilatation and systolic dysfunction
Dilated hypokinetic left ventricle - FS% less than 25%
Increased LVID-D and LVID-S
May also see - LAE, Mitral insufficiency
