Acquired CV Disease Dogs Flashcards
What are the 3 most common/main acquired CV diseases in DOGS?
- Degenerative mitral valve disease (DMVD)
- Dilated cardiomyopathy (DCM)
- Pericardial effusion
Which dogs are commonly affected by degenerative mitral valve disease?
older small breed dogs, but any old dogs can be affected
- esp CKC
How does mitral valve degeneration progress? What clinical sign will be noticed first?
Slowly!
- left apical systolic murmur
- may remain this way for ~3 years + before developing heart failure
- in many cases dogs die from another condition
- <50% dogs with DMVD will go into heart failure and die from this disease
How will a mitral murmur change with disease progression?
gets louder
- can be > grade 3/6 without yet going into heart failure
PE findings with DMVD?
- left apical systolic murmur
- ^ HR
- lack of sinus arrythmia
- loss of BCS
- breathlessness/coughing
- crackles on the lungs
How can mitral valve disease be graded?
B1: no cardiomegaly, no clinical signs
B2: cardiomegaly but no clinical signs
C: signs of heart failure
D: heart fialure refractory to Tx
How may a definitive dx of DMVD be attained?
Radiography for heart failure (Left sided usually goes first -> pulmonary oedema etc.)
Echo to demonstrate mitral regurgitation
Doppler echocardiography
- this is usually not necessary as presumptive Dx possible
> looking for progressive left sided enlargement
When is therapy indicated?
Stage C disease only (signs of heart failure)
- treat symptomatically
- no evidence that earlier treatment is advantagous
What is the Tx for heart failure in dogs?
- Frusemide (diuretic)
- Pimobendan
- ACEI
- Spironolactone
> ^ doses until disease becomes refractory to drugs
Prognosis of DMVD?
- depends on whether they show signs of heart failure
- < 1/2 without signs of failure succumb to the disease
- once in heart failure average sruvival <1year
What is the 2nd most commonly diagnosed cardiac disease?
> dilated cardiomyopathy (and arrythmogenic RV cardiomyopathy also common)
- sudden death possible with this
What dogs are usually affected by DCM?
- large breed eg. dobermans, boxers
- prevalence ^ with age
- males may be more at risk
- peak age of detection 5-10years
How does the diagnosis of DCM differ to DVMD?
- unlikely to pick up on routine PE as an incidental finding as you would for DMVD
- pre-clinical signs more subtle in occult stage
How long does DCM take to progress to heart failure?
can be low as 20 weeks from dx
What concurrent finding is seen with DCM?
- arrythmia
- can potentially have soft left apical systolic murmur but not always
Which disease has the potential for sudden death to be the first clinical sign?
DCM
Diagnostics for DCM?
- echo to show dilation of heart and impaired systole
- ECG for cardiac arrythmias (24hour Holter?)
- radiographs to determine heart failure
Is pre-clinical treatment of DCM advocated?
YES!
- Pimobendan delays onset of clinical signs and prolongs life (in dobermans)
- ACEI may be beneficial
Tx of DCM once heart failure has occourred?
similar to DMVD
- furosemide, pimobendan, ACEI
- potentially spironolactone but less evidence in DCM
Prognosis for DCM with heart failure?
- guarded
- cockers can live longer
- dobermans and great danes do less well
What are the 2 potential causes of pericardial effusion?
- idiopathic
- neoplasia (echo to look for mass though may not see it)
which breeds are predisposed to develop pericardial effusion?
- lab retrievers
- german shephards
- St. bernards
When does pericardial effusion develop?
Mid - old age
- st. bernards can develop earlier
Clinical signs of pericardial effusion?
- Forward (weakness, syncope) AND backwards (pulmonary oedema, ascites) failure
- Right heart usually affected worse due to thin walls
- only cause of predominant RIGHT sided heart failure in dogs*
- fluid v venous return -> v CO
- necessitates ^ cardiac filling pressures
What type of failure do DCM, pericardial effusion and DMVD cause?
DCM and DMVD Left sided
Pericardial effusion Right sided
What is cardiac tamponade?
so much pericardial effusion heart cannot beat
What does sudden and chornic decrease in CO cause?
- sudden eg haemorrhage -> collapse
- chronic -> RCHF, lethargy, ascites, cough
PE findings of pericardial effusion
- muffled heart sounds
- v intensity of the apex beat
- pulsus paradoxus (intensity of femoral pulse decreases during inspiration)
- RHF (ascites, jugular distension, pleural effusion and ^ resp effort)
- NO HEART MURMUR (this disease may be missed!!)
Disagnosing pericardial effusion?
- echo
- ECG may show decreased amplitude of QRS complexes, and beat to beat alternation in the amplitude of the QRS complexes (electrical alternans)
Tx of pericardial effusion
- NOT MEDICAL!
- drain fluid (pericardiocentesis)
> right side under US guidance
Prognosis for pericardial effusion?
> with neoplasia, POOR
idiopathic - may experience no recurrence after drainage, but may recurr
- pericardiotomy and pericardiectomy to allow fluid drainage into the pleural space where it can be absorbed.
Good summary table in lecture notes§
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