Canine dilated cardiomyopathy and other myocardial diseases Flashcards
What is a cardiomyopathy?
Myocardial disorder in which the heart muscle
is structurally and functionally abnormal
What are examples of primary cardiomyopathies?
- Dilated cardiomyopathy (DCM)
MOST COMMON - Arrhythmogenic right ventricular cardiomyopathy (ARVC)
- Hypertrophic cardiomyopathy (HCM)
- Atrial cardiomyopathy (can also be called atrial standstill)
What are secondary cardiomyopathies?
- Tachycardia induced (TICM)
- Systemic hypertension
- Drugs/Toxins
- Infiltrative disease
- Metabolic/endocrine e.g. hyperthyroid
- Nutritional - Taurine, L-Carnitine, Grain free diet
- Inflammatory (myocarditis) - Infectious, Non-infectious
- Connective tissue disease (RARE) -Muscular dystrophy (GR, GSD)
What does dilated cardiomyopathies cause/ lead to? What animals is it seen in?
- Large breeds
- Adult onset (usually)
- Guarded prognosis
- CHF
- Sudden death
*Impaired systolic function
*Dilated cardiac chambers - Thin walls
- Mitral regurgitation
What breeds are predisposed for DCM?
- Dobermans++ - sudden death
- Great dane
- Newfoundland
What is the pathology of DCM?
- Dilation of all chambers - HW:BW increased
- Mitral / tricuspid annulus stretched
What happens as DCM progresses?
- Damaged cells no longer function effectively
- Cell death + fatty / fibrous replacement
=impaired systolic function
What is Arrhythmogenic right ventricular cardiomyopathy seen in? (ARVC)
- Boxer ++
- English bulldog
- Dogue de Bordeaux
What is the pathology + histopath of ARVC?
Gross pathology:
* Right ventricular dilation, wall thinning (BUT DOES NOT ALWAYS BECOME VISIBLE)
Histopathology:
* loss of myocytes with fatty/fibrofatty replacement
What are the 3 presentations of ARVC?
- Asymptomatic with VPCs
- Symptomatic with VPCs
- Ventricular dilation, myocardial dysfunction, arrhythmias
What dogs get atrial cardiomyopathy?
- English springer spaniel
- Labrador
What does get hypertrophic cardiomyopathy?
- Terriers
- Pointer dogs
- Golden retrievers
What can cause secondary cardiomyopathies?
- Myocarditis - viral, autoimmune, inflammation
- Tachycardia induced
- Taurine deficiency
How do you recognise a dog with DCM?
- Larger breeds
- Arrhythmia
- Quiet, soft murmur
- Dyspnoea, tachypnoea, crackles
- Older dogs
- Hx of collapse
- Exercise intolerance
- Cough
What can cause poor contractility in older dogs?
- Hypothyroidism - always rule out
