Degenerative valvular disease

Question 1

Degenerative valvular disease
- typical signalment and clinical signs?
- top of the list diagnostic test?

Answer 1

• small breed dogs
• 7-8 years old
• heart murmur
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  § Dog is quieter, less exercise tolerant, occasional cough
  § Tachypnea
  § Tachycardia
  § Extra beats, pulse deficits
  § left sided systolic apical heart murmur
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• thoracic radiographs

Question 2

elevated respiration rate, heart murmur, cough
- what diagnostics should we prioritize based on these signs?

Answer 2

1. Thoracic radiographs!!!
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   If we have them:
2. Echocardiography > dx, severity
3. ECG
4. Bloods > kidney, electrolytes

Question 3

mitral insufficiency
- what occurs?
- what changes to the heart? why?

Answer 3

• when the ventricles contract, some of the blood goes backwards into the left atrium, instead of pumping all the blood into the aorta
  > we always have more blood in the left atrium
  > eft atrium enlarges
  > more volume is pumped into the left ventricle
  > left ventricle becomes larger
  > now its really easy for the ventricle to contract; usually, it needs to pump all the blood into the aorta which has high pressure, but the pressure in the left atrium is really low > so, our contractility will look really good, but only because the heart is having an easy time pumping blood from the left ventricle back into the left atrium!
  > so the function is not truly good, but the work for the heart is easier
  > heart gets bigger and bigger over time, valves get worse…

Question 4

significance of seeing occasional supraventricular premature complexes on ECG?

Answer 4

• we ignore them - we already know the animal has some heart disease

Question 5

if we suspect valvular heart disease, what radiographic, ECG, echocardiography, and blood results do we expect to find?

Answer 5

§ Radiographs: cardiomegaly (left atrium), pulmonary edema, distended pulmonary veins
§ Echocardiography: thickened MV leaflets, severe mitral regurgitation
§ ECG: Sinus tachycardia with SVPC
§ Blood: unremarkable

Question 6

heart failure - what is the result of our compensatory mechanisms from the SNS and RAAS?
- what are our treatment goals

Answer 6

Increased preload: Fluid retention
Increased afterload: Vasocon-
striction
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- we want to get of fluid and pulmonary edema
- increase contractility
- we want to vasodilate so its easier for the heart to pump
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- venodilators (ACEi)
- Diuretics (furosemide)
- Inotropes (pimobendan)
- Anti-remodelling (ACEi, spironolactone)
- Arteriodilators (ACEi)

Question 7

heart failure treatments and rationale

Answer 7

• Pulmonary edema (reduce preload): Furosemide (loop- diuretic)
• Contractility: Pimobendan (inodilator)
• RAAS inhibition (reduce preload + afterload): ACE-inhibitor
  (vasodilator, reduced Na and H2O retention)
• Remodelling: Spironolactone (anti-aldosterone)

Question 8

follow up after heart failure treatment

Answer 8

§ Discharge home, monitor resting respiration rate at home
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§ First 1-2 weeks
§ Repeat blood > ensure kidney values remain stable
§ Repeat radiographs? depends on how well the dog does. if dog not responding how we want, repeat.
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§ Revisit in 3 months, earlier if concerns

Question 9

What not to do! in a case of heart failure

Answer 9

Do not give fluids (even if azotemia)!
§ Reduce diuretic - close monitoring
§ End of life conversation
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Sedation/anesthesia:
§ No vasoconstriction (do not use dexmedetomidine)
§ Hypotension favours forward cardiac output
§ No fluid bolus, high-rate infusion

Question 10

Degenerative valvular disease usual presentation, progression

Answer 10

§ Small breed dogs
§ Most common cardiac disease
§ Adult onset
§ Murmur years before onset of heart failure
> Slow progression, might not develop heart failure

Question 11

Valvular disease, heart failure
- usual pathogenesis

Answer 11

§ Mitral regurgitation
§ Increased left atrial volume, pressure → pulmonary edema
§ Remodelling, myocardial failure

Question 12

heart failure classifications - which do and dont need treatment?

Answer 12

No treatment:
A: Risk of heart disease
B: Heart disease, no clinical signs
◦B1: No chamber enlargement
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Treatment:
◦B2: Enlargement left atrium/ventricle
C: Past or current signs of heart failure
D: End-stage disease, refractory to standard therapy

Question 13

criteria for starting a dog on treatment with pimobendan for vavlular disease, even if not in heart failure - who will benefit??

Answer 13

Fulfil all the following:
§ Small breed dog (< 20 kg)
§ Grade 3/6 left sided systolic apical heart murmur
§ Vertebra heart sum (VHS) > 10.5
§ Echocardiography LA and LV enlargement
> LA enlargement (LA/Ao 3 1.6)
> LV enlargement (LVIDdN 3 1.7)
§ If no access to echocardiography: VHS >11.5, VLAS of ≥ 3

Question 14

Degenerative valvular disease, CHF - treatment

Answer 14

In heart failure (C/D):
§ Furosemide!!
§ Pimobendan!
§ ACE-inhibitor
§ Spironolactone

Question 15

valvular disease summary
- which dogs should we suspect?
- what criteria should we gather, and what should we do based on each?

Answer 15

§ Common in older small breed dogs § Heart murmur!
§ Not all dogs with valvular disease will develop CHF!
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§ Grade 3/6: thoracic radiographs – VHS
§ VHS < 10.5: repeat radiographs in 3-6 month (no treatment) § VHS > 10.5: echocardiography – B2 (pimobendan)
> Diagnose disease

Question 16

signs we expect for CHF patients? what dx test should we do?
- CHF C, D treatments (in order of importance)
- monitoring?

Answer 16

§ CHF: heart rate, respiration rate increased, cough:
> Thoracic radiographs
§ CHF (C, D): furosemide, pimobendan, ACEi, spironolactone
§ Respiration rate for monitoring