Cardio3- Canine Cardiomyopathies

  1. What are the main canine cardiomyopathies? (3)
    • dilated cardiomyopathy (DCM), arrhythmogenic right ventricular CM (ARRV)
    • persistent atrial standstill (atrial CM)
  2. What are secondary cardiomyopathies that occur in dogs? (6)
    myocarditis, hypothyroidism, CM of chronic volume overload, CM of chronic pressure overload, tachycardia-induced CM, drug-induced CM (doxorubicin, monensin)
  3. What is DCM?
    primary heart muscle disease characterized by cardiac dilatation and systolic dysfunction of one or both ventricles
  4. What are hypothesized causes of canine DCM? (5)
    familial/genetic, immune-mediated, viral, metabolic, nutritional
  5. What is the mutation related to Boxer ARVC?
  6. What is the mutation associated with Doberman DCM?
  7. Canine DCM is a(n) ___________ disease, with different phenotypes in _____________.
    heterogenous; different breeds
  8. What breeds are commonly associated with CM, and which does each breed get? (4)
    Doberman Pinscher (genetic DCM), Boxer (genetic ARVC), American Cocker Spaniel (taurine/carnitine), Springer/Sussex Spaniel (atrial CM)
  9. Cardiomyopathies are most common in... [signalement]
    large breed, male, middle aged dogs
  10. What are the 3 clinical phases of canine CM?
    genetic predisposition--> preclinical (occult) phase (arrhythmias)--> heart failure (weakness, exercise intolerance, syncope, weight loss, CHF, sudden cardiac death)
  11. What clinical signs are associated with the heart failure phase of canine CM? (6)
    weakness, exercise intolerance, syncope, weight loss, CHF, sudden cardiac death
  12. What are the most common presentations of Doberman DCM? (4)
    ventricular arrhythmias (LV VPCs), syncope, sudden death, L-CHF (sometimes R)
  13. What PE findings might be associated with Doberman DCM? (5)
    soft systolic murmur, S3 gallop, arrhythmia w/ pulse deficit, weak arterial pulses, L-CHF/biventricular CHF
  14. Why is the murmur associated with Doberman DCM always soft?
    ventricles that cannot contract properly will never develop a loud murmur
  15. What ECG findings are common with Doberman DCM? (4)
    often sinus rhythm or sinus tachy, left VPCs, ST segment depression, wide QRS complexes
  16. How do we detect occult DCM in Dobies? What are common initial abnormalities?
    Holter ECG for 24 hours; only VPCs/ ventricular ectopy
  17. What radiographic findings are common with Doberman DCM? (4)
    left-sided enlargement, pulmonary venous distention, perihilar/ patchy distribution of pulmonary edema, +/- pleural effusion
  18. Echo findings with Doberman DCM. (5)
    [confirm diagnosis] LA and LV dilatation with wall thinning, LV systolic dysfunction, secondary mitral regurg (mitral valve may look normal!!), restrictive LV filling, evidence of pulmonary hypertension
  19. What do you see on M-mode with Doberman DCM?
    LV hypokinesia (small SF)
  20. What are the key problems that need to be addressed with Doberman DCM? (5)
    increased preload, increased afterload, decreased systolic function, tachyarrhythmia, myocardial remodeling
  21. What is the treatment plan for symptomatic Doberman DCM? (7)
    diuretics, ACEi, low salt diet, Pimobendan, Digitalis and/or Diltiazem (if supraventricular tachyarrhythmia), Sotalol or Mexiletine (if ventricular tachyarrhythmia), Spironolactone/ Carvedilol, ACEi, Fish oils (cardioprotection)
  22. How do you handle occult Doberman DCM? (5)
    cardiac protection (ACEi, fish oils), mild exercise restriction, Pimobendan (if chamber enlargement), ACEi (prevent volume overload), Sotalol or Mexiletine(if vtach arrhythmia)
  23. What is the acute therapy for CHF in a dog with CM? (7)
    • [FONTS Plus]
    • Furosemide, Oxygen, Nitroglycerine, Sedation, Tapping (if effusion), Pimobendan
    • Cardiogenic shock?--> Dobutamine
  24. What is the chronic therapy for CHF in a dog with CM? (6)
    furosemide, enalapril, pimobendan, digoxin +diltiazem (if afib), spironolactone, +/- fish oil
  25. What is the prognosis for Doberman DCM?
    • was poor before Pimobendan
    • with Pimobendan, <1 year
  26. What are characteristics of Cocker Spaniel DCM? (4)
    adult onset, L or R-CHF, reversible, good prognosis with taurine and carnitine supplementation
  27. Persistent atrial standstill (atrial CM) occurs most commonly in __________ as a result of...
    English Springer Spaniels; selective destruction of atrial myocardium, resulting in atrial standstill.
  28. What are early clinical signs of atrial CM? (4)
    exercise intolerance, weakness, syncope, R-CHF
  29. What are ECG findings with atrial CM in Springer Spaniels? (2)
    very small P waves (may be absent), nodal and ventricular escapes
  30. What are gross and microscopic findings with atrial CM? (1 of each)
    severe RA and RV dilatation, massive loss of myofibers
  31. What is the therapy for atrial CM? (2)
    symptomatic treatment of heart failure, cardiac pacemaker
  32. What is Irish Wolfhound CM?
    "lone" atrial fibrillation that can later develop into full blown DCM
  33. In late disease, what are findings associated with Irish Wolfhound CM? (2)
    pleural effusion, often chylous
  34. What is the therapy and prognosis for Irish Wolfhound CM?
    • Therapy: Digoxin and Diltiazem, if develop CHF, standard txt
    • Prognosis: good
  35. What is Boxer ARVC? (5 characteristics)
    primary myocardial disease characterized by RV tachyarrhythmias, syncope, sudden death, heart muscle atrophy, fatty infiltration of RV free wall
  36. What are the categories of Boxer ARVC? (3)
    • Category I: asymptomatic
    • Category II: collapse and syncope
    • Category III: L-CHF
  37. All 3 categories of Boxer ARVC are characterized by ___________.
    RV arrhythmias (sometimesatrial arrhythmias)
  38. What are echo findings with Boxer ARVC?
    • categories I and II are normal on echo
    • category III has RV dilatation on echo
  39. What are ECG findings common with Boxer ARVC? (3)
    RV bigeminy with sinus and VPCs, right axis shift, RV vtach
  40. How are arrhythmias associated with Boxer ARVC often discovered?
    Holter ECG for 24 hours
  41. What is the therapy for Boxer ARVC? (5)
    • [if symptomatic] [SPAM] Sotalol, Procainamide, Amiodarone, Atenolol, Mexiletine
    • +/- fish oils
  42. What are primary causes of myocarditis? (5)
    Chagas' myocarditis (T. cruzi), Parvovirus, Toxoplasma, Neospora, Lyme
  43. What are the stages of Chagas' myocarditis and what does each cause? (2)
    • Acute: arrhythmia (most common AV block)
    • Chronic: right side myocardial failure, ventricular ectopy
  44. What are secondary causes of myocarditis? (2)
    bacterial and septic
  45. What drugs are commonly used to treat acute (in hospital) ventricular ectopy in a dog? (5)
    • [First line] IV lidocaine
    • [Second line] IV procainamide, amiodarone, esmolol, magnesium salts
  46. What drugs are used for the chronic (home treatment) of ventricular ectopy in dogs? (5)
    [SPAAM] sotalol, procainamide, amiodarone, atenolol, mexiletine
  47. What are differentials for LV hypokinesia in a dog? (4)
    DCM, taurine deficiency, volume overload (valve regurg, shunts, RAAS activation), end-stage heart failure
Card Set
Cardio3- Canine Cardiomyopathies
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