Acquired cardiovascular disease in dogs

Question 1

most common diseases

Answer 1

Degenerative (acquired) mitral valve disease
Endocardiosis
Myxomatous valve disease
Dilated cardiomyopathy
Pericardial effusion
Neoplastic
Idiopathic

Question 2

degenerative mitral valve disease (DMVD) - pathophysiology

Answer 2

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

Question 3

DMVD - history

Answer 3

older dogs
smaller breeds
affects males earlier

Question 4

DMVD - clinical signs

Answer 4

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

Question 5

DMVD - Diagnostic evaluation

Answer 5

Clinical examination
E.C.G.
Radiography
Echocardiography
Blood tests

Question 6

DMVD - clinical exam

Answer 6

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

Question 7

DMVD - electrocardiogram

Answer 7

usually normal
may see hypertrophy pattern
rarely rhythm disturbance

Question 8

DMVD - radiography

Answer 8

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

Question 9

DMVD - echocardiography

Answer 9

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

Question 10

DMVD - definitive diagnosis

Answer 10

Doppler echocardiography
Demonstrate regurgitant flow
Colour flow
Spectral

Question 11

DMVD - treatment regime - heart failure

Answer 11

Diuretic
Pimobendan
ACE inhibitor
Spironolactone

Question 12

pimobendan

Answer 12

calcium sensitizer with positive inotropic and vasodilator effects
selective inhibitor of phosphodiesterase III (PDE3)
smaller cardiac preload and afterload

Question 13

bacterial endocarditis

Answer 13

Rare disease

Infection of Endocardium, typically valvular

Question 14

bacterial endocarditis - clinical signs

Answer 14

Pyrexia of unknown origin
Lameness
Sepsis

Question 15

bacterial endocarditis - diagnosis

Answer 15

Echocardiography, Blood cultures, changing murmur

Question 16

bacterial endocarditis - treatment

Answer 16

Appropriate antibiotic therapy over many weeks

Question 17

bacterial endocarditis - prognosis

Answer 17

guarded

Question 18

types of cardiomyopathy

Answer 18

dilated (common)
hypertrophic (v.rare in dogs)
restrictive
Arrhythmogenic right ventricular cardiomyopathy
Intermediate/Unclassified

Question 19

dilated cardiomyopathy

Answer 19

Systolic failure of myocardium
Dilatation of the ventricle due to increased end diastolic pressures
May lead to valvular insufficiency secondary to dilatation.
Aetiology unclear

Question 20

dilated cardiomyopathy - clinical signs

Answer 20

may be incidental finding
forward and/or backward failure
Forward failure -intermittent collapse, weakness, sudden death
Backward failure -cough, exercise intolerance, dyspnoea, ascites

Question 21

dilated cardiomyopathy - physical exam

Answer 21

Findings variable
Systolic murmur (likely to be softer than DMVD)
Gallop rhythm
Arrhythmia, pulse deficits (more likely that in DMVD)
Signs of CHF

Question 22

dilated cardiomyopathy - ECG

Answer 22

Variety of rhythm disturbances can occur
Sinus tachycardia
A.P.C.’s
A.F.
V.P.C.’s
Paroxysmal V. Tach

Question 23

dilated cardiomyopathy - radiography

Answer 23

findings supportive but not diagnostic
Evidence of cardiomegaly - Generalised, LVH, LAE
Evidence of congestive failure - LCHF, Pulmonary oedema + congestion
RCHF - Ascites, Pleural effusion

Question 24

dilated cardiomyopathy - echo

Answer 24

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

Question 25

indices of systolic function

Answer 25

Fractional shortening
Ejection fraction
Systolic time intervals
Doppler tissue imaging