Canine Myocardial Disease

Question 1

What’s the most common signalment for dilated cardiomyopathy?

Answer 1

medium to large breed
- Doberman Pincher, Irish Wolfhound, Great Dane, Cocker Spaniel

Question 2

What abnormalities can be noted on physical exam for DCM?

Answer 2

There are 2 stages: asymptomatic and symptomatic
- symptomatic: soft murmur and/or gallop rhythm

Question 3

Which biomarker is the most useful for detecting both occult and overt DCM?

Answer 3

NT-proBNP

Question 4

What would an underlying condition that can lead to DCM in Cocker Spaniels?

Answer 4

Taurine deficiency

Question 5

What type of diet could potential increase risk of DCM in dalmatian?

Answer 5

low protein

Question 6

What are some screening criteria for adult Doberman for DCM?

Answer 6

On echocardiogram: mild enlargement of L ventricle
On ECG: more than 50 VPCs in 24h, or with couples or triplets

Question 7

What’s the most common presenting signs for Great Dane with DCM?

Answer 7

• weight loss, coughing
• may be X-linked
• ECG = atrial fibrillation with occasional VPCs

Question 8

What’s the disease progression of DCM in Irish Wolfhounds?

Answer 8

• autosomal recessive
• tends to be slower
• atrial fibrillation may be the first sign, and no CHF until 2 years later
• sudden death still possible

Question 9

How common is heart murmur for Newfoundland with DCM?

Answer 9

• not common!
• still has atrial fibrillation, some VPCs
• common complaint = dyspnea, cough, inappetance, ascites with L or biventricular heart failure
• no gender predilection

Question 10

At what age can Portuguese Water Dog develop DCM?

Answer 10

They have a juvenile form of familial DCM that can occur at 2-32 weeks old
- sudden collapse/ death possible
(similar to Toy Manchester terriers)

Question 11

What’s the pattern of inheritance for familiar Giant Schnauzer with DCM?

Answer 11

Autosomal recessive

Question 12

At what age can Toy Manchester terriers develop DCM?

Answer 12

< 1 years old, similar to Portuguese Water dog

Question 13

How is occult DCM treated?

Answer 13

• ACEi
• Pimobendan
• cautious with beta blockers

Question 14

How is overt DMC treated?

Answer 14

• Pimobendan –> balanced vasodilation, positive inotrope
• ACEi
• diuretics

Question 15

How is ventricular arrhythmia managed in patients with DCM?

Answer 15

• not sure if treatment is truly warranted as the association with sudden death is not well studied
• if needed, can try beta blocker (ex. sotalol) and potassium channel blocker (ex. amiodarone) –> use cautiously if systolic dysfunction is presnet

Question 16

What’s the most common clinical signs of boxer cardiomyopathy?

Answer 16

aka arrhythmogenic right ventricular cardiomyopathy
- ventricular arrhythmia
- syncope = most common
- sudden death

Question 17

How is Boxer cardiomyopathy diagnosed?

Answer 17

• Holter: >100 VPCs. left BBB, couplets, or triplets
• CXR = often normal
• Echo = looks for ventricular dilation and systolic function – may still be normal

Question 18

When should Boxer cardiomyopathy be treated?

Answer 18

• could consider treatment is there is:
  >1000 VPCs in 24hs
  ventricular tachycardia
  evidence of R-on-T phenomenon
  homozygous for the striation mutation (known to have more sever disease)
• but anti-arrhythmic for ventricular arrhythmia can also lead to more arrhythmia, and there is no clear indications that treatment will decrease the risk of sudden death

Question 19

How is Boxer cardiomyopathy treated?

Answer 19

With syncope and ventricular tachycardia:
- sotalol, maxiletine
If there is echo findings of systolic dysfunctions and ventricular dilation –> treat like DCM
- pimobendan, ACEi, diuretics

Question 20

What’s myocarditis?

Answer 20

presence of myocardial necrosis, or degeneration & inflammation

Question 21

What are some infectious agents that can cause myocarditis?

Answer 21

1. Chagas’ disease (Trypanosoma cruzi)
   - R sided heart failure
   - ECG abnormalities
   - sudden death
   - lymphadenopathy!
2. Leishmania
   - parasite can be in the myocardium
   - 1st degree AV block
3. Parvo enteritis (uncommon cause for myocarditis)
4. West Nile (also uncommon cause of myocarditis)

Question 22

What are some other uncommon causes of myocardial disease in dogs?

Answer 22

• hypothyroidism –> reduction in L ventricular fractional shortening
• myocardial infarcts –> associated with thromboembolic state
• hypertrophic cardiomyopathy –> concentric hypertrophy of the interventricular septum and L ventricular free wall