Small animal canine DCM + other myocardial dx

What are the primary cardiomyopathies to know?

• DCM (most common)

• Arrythmogenic right ventricular cardiomyopathy

• HCM

• Atrial cardiomyopathy/ Atrial standstill

List some of the causes of secondary cardiomyopathy

• Tachycardia induced (TICM)

• Systemic hypertension

• Drugs/Toxins

• Infiltrative disease

• Metabolic/endocrine e.g. hyperthyroid

• Nutritional

  • Taurine

  • L-Carnitine

  • Grain free diet

• Inflammatory (myocarditis)

• Connective tissue disease (RARE)

  • Muscular dystrophy (GR, GSD)

What is the typical presentation of DCM?

• Large breeds

• Adult onset

(Guarded prognosis)

What changes does DCM cause in the heart?

• Impaired systolic function

• Dilated cardiac chambers (All 4 but L>R)

• Thin walls

• Mitral regurgitation? from walls being 'pulled apart'

Which 3 breeds have the largest incidence of DCM?

• Dobermann (2 in 3)

• Great Danes (1 in 3)

• Newfoundlands (1 in 5)

  

What main histopath changes are seen in DCM?

• Attenuated fibres (atrophied)

  

• Fibro fatty infiltration

  

Explain the sequelae of DCM

• Also mitral annulus stretch so mitral regurg too

What are the similarities between MDVD vs DCM?

• Enlargement of left ventricle (+/- right)

• Enlargement of left atrium

• Mitral regurgitation

What are the differences between MDVD v DCM?

• Contractility maintained in MDVD which is why you get lots of MR

• MDVD harsh murmur cf to DCM softer murmur (easier to miss)

List some of the breed variation in DCM

• Dobermann- high prev, long asymptomatic preclin

• Great danes- freq VPCs, sudden death

• Irish wolfhound- Afib

• Cocker - slower progression, taurine

• Portuguese water dogs- juveile onset, highly aggressive

What can cause nutritional DCM?

• Grain free diet

• Taurine deficiency

What breeds are typically predisp to ARVC? What is the prognosis?

• Boxer

• Also other big brachys- english bulldog, dog de bordeaux

• 11y but that is typical lifespan anyways, inc sudden death

What is the gross path of ARVC?

Right ventricular dilation, wall thinning (BUT DOES NOT ALWAYS BECOME VISIBLE)

What are the three presentation possibilites of ARVC?

1. Asymptomatic with VPCs

2. Symptomatic with VPCs

3. Ventricular dilation, myocardial dysfunction, arrhythmias

How does atrial cardiomyopathy present?

• Thinning atrial walls

• No p waves (atrial standstill)

• LA>>>>>>LV

• Syncope main sign - pacemaker

What is the typical patient that has atrial standstill?

• ESS, Labrador

• Younger (med. 3yo)

• Median survival 4-4.5 post pacemaker

What can lead to a DCM like phenotype?

• Myocarditis

• TICM (AF, SVT, VT can produce same effect)

• Taurine deficiency

How might you identifiy a DCM case in a consult?

• Large breed

• Arrythmia

• Soft, quiet, left apex murmur

• Resp signs if in failure (incl cough)

• Collapse quite common

• A lot are Asym

Compare DCM to MDVD

What investigations would you do for DCM?

• History + physical examination

• Blood pressure- could be low if forward failure, or high bc afterload inc

• Clinical pathology- pre renal, electrolytes, hypothyroid

  • Biomarkers- NTproBNP and Troponin

• ECG- Afib, VPCs, SVPCs

• Radiography

• Echocardiography

• Ambulatory ECG

Compare the ECG arrythmias you would find in DCM cf to MDVD?

Cardiac xray analysis

Compare DCM echo findings compared to MDVD

Compare normal vs DCM M mode

How would you treat preclinical DCM?

Pimobendan

• Inc 9 months clinical symptom free time

Recall congestive heart failure treatment

• Furosemide

  • + other diuretics?

• Pimobendan

• ACE-inhibitors

• Spironolactone

What other treatments can you add for CHF other than PFAS?

Arrythmias

• SV- diltiazem and digoxin

• V- Sotalol

Pulmonary hypertension

• Sildenafil