Acquired Cardiovascular Disease in Dogs Flashcards
What are the most common heart diseases in dogs?
- DMVD
- DCM
- Pericardial effusion
Describe mitral value disease pathophysiology..
- Distortion of valve leaflets due to degenerative change
- Results in development of insufficiency (regurg)
- Need an increase in ventricular stroke volume
- Leads to ventricular dilation
- Worsens leakage of valve
- Responds with vasoconstriction, which worsens condition
What do the valves look like in degenerative mitral valve disease?
Nodular - myxomatous changes/endocarditis
What is the signalment for mitral valve disease?
- Typically older dogs
- Small dogs (<25kg) e.g. CKCS, terriers, chihuahua
- Affects males earlier
What are the 4 steps in the DMVD staging pyramid?
B1 - murmur, no cardiomegaly, no signs
B2 - cardiomegaly, no signs
C - Signs of heart failure
D - refractory signs of heart failure
What are the clinical signs of DMVD?
Incidental finding Signs of LSF e.g. cough, dyspnoea, exercise intolerance Signs of collapse e.g. dysrrhythmias Sudden death rare but due to arrhythmia, left atrial treat, ruptured chord Signs of RHSF later in disease
What are the clinical findings with mild DVMD disease?
Left apical systolic murmur +/- exercise intolerance
Otherwise normal
What are the clinical findings of moderate DVMD disease?
Murmur higher grade Dyspnoea Tachycardia Dysrrhythmias Crackles/wheezes
What are the clinical findings of severe DVMD disease?
CHF! Higher grade murmur Dyspnoea Tachycardia Dysrrhythmia Crackles/wheezes Progress to RCHF - Ascites, juglar pulse, hepatomegaly
What are you likely to find on ECG when looking for dilated mitral valve disease?
Usually normal
- May see pattern consistent with hypertrophy
- Rhythm disturbance (rare)
What may you find on radiography when looking for DVMD?
LA enlargement LV enlargement Bronchial compression Pulmonary venous congestion Pulmonary oedema RCHF - Pleural effusion - Ascites - Hepatomegaly
What may you find on echo when looking for DVMD?
Valvular changes
- Rough irregular leaflets
- Prolapse ruptured chordae
- Failure of apposition
Chamber enlargement
- both LA and LV
Myocardial function
- altered fractional shortening
What will give you a definitive diagnosis of DMVD?
Doppler echocardiography
Demonstrates regurgitant flow
What is the best evidence treatment for DVMD?
a. Prior to onset of CHF signs
b. After onset of CHF signs
a. Pimobendan in stage B2
b. Furosemide and pimobendan - also consider ACEi and spironolactone
Why is pimobendan good at treating DMVD?
Arteriodilator which increase the diameter of the aorta, making it easier for blood to flow through aorta rather than back into atrium
What are the signs of bacterial endocarditis in dogs? Is it common?
Rare
- Murmur that changes
- PUO
- Lameness
- Sepsis
How might you diagnose and treat bacterial endocarditis and what is the prognosis?
Diagnosis:
Echocardiography
Blood cultures
Changing murmur
Treatment:
Antibiotic therapy over many weeks
Prognosis is poor
Common cardiomyopathies in the dog?
Dilated cardiomyopathy
Sometimes arrhythmogenic right ventricular cardiomyopathy
What is DCM?
Systolic failure of myocardium
Dilation of the ventricle due to increased end diastolic pressures
- May lead to valvular insufficiency secondary
What are the clinical signs of DCM?
Incidental finding Signs of forward failure \+ Intermittent collapse \+ Weakness \+ Sudden death
Signs of backwards failure \+ Cough \+ Exercise intolerance \+ Dyspnoea \+ Ascites
What is the occult phase of DCM?
Where there is early myocardial disease but no signs of heart failure.
What physical exam findings are suggestive of DCM?
Systolic murmur Gallop rhythm Arrhythmias, pulse deficits Signs of CHF \+ Dyspnoea, crackles, cough \+ Ascites, pleural effusion, subcutaneous oedema.
What may you find on ECG when looking for DCM?
Variety of rhythm disturbances: Sinus tachycardia AF APC VPC Paroxysimal ventricular tachycardia
What may you find on radiography when looking for DCM?
Cardiomegaly
Generalised
LV hypertrophy
LA enlargement
LCHF
Pulmonary oedema
Pulmonary congestion
RCHF
Ascites
Pleural effusion
What may you find on echocardiography suggestive of DCM?
Dilation of LV
Fractional shortening <25%
LA enlargement
Mitral insufficiency
What is fractional shortening? What % indicates DCM?
Degree to which ventricular diameter reduced from diastole to systole
<25%
What is the best evidence treatment for DCM?
a. Prior to onset of signs of CHF
b. After onset of signs CHF
a. Pimobendan - possibly ACEi
b. Furosemide, ACEi and pimobendan
Consider also giving antirrhythmic drugs because they often have accompanying arrhythmias
What are your treatment options for heart failure once best evidence treatment has been exhausted?
Optimise cardiac rate and rhythm
Control of rate in atrial fibrillation
Control severity of rhythm disturbance with VTach
Antagonise neurohormonal mechanisms
ACE inhibitors, beta-blockers, spironolactone
Nutritional support
What causes pericardial effusions in dogs?
Idiopathic pericarditis Neoplasia - RA haemangiosarc - Mesothelioma Rarely - trauma, hypoproteinaemia, RCHF, FBs,
What is the pathophysiology of pericardial effusions?
Increase in pressure within pericardial sac compromises diastolic function
Right side affected more due to thin walled right ventricle
Results in development in RCHF
If acute may see signs of syncope and forward failure
What are the clinical signs of pericardial effusion?
Acute onset Lethargy RCHF - Ascites - Dyspnoea - Collapse - History of coughing
What on clinical exam is suggestive of pericardial effusion?
Signs of RCHF - Jugular distension - Ascites - Hepatomegaly Muffled heart sounds No murmur
What on ECG is suggestive of pericardial effusion?
Small QRS complexes
What on radiography is suggestive of a pericardial effusion?
Generalised enlargement of the cardiac silhouette +/- RCHF signs
What are the echocardiography findings suggestive of pericardial effusion?
Presence of fluid
Possible indicators e.g. neoplasia
May show cardiac tamponade
- collapse of RA and RV during diastole
What is the treatment for pericardial effusion?
Pericardiocentesis
What is the prognosis for dogs with pericardial effusion?
Dependent on underlying causes
Idiopathic disease may be cured by drainage but has tendency to reoccur
Neoplasia poor
FB/infectious manageable by surgery
