Valvular heart diseases

Question 1

What is the most common cardiac disease?

Answer 1

• Myxomatous degenerative valve disease - dogs, horses, pigs, humans

Question 2

What dogs tend to get MDVD?

Answer 2

• Old dogs
• Small breeds

Acquired

Question 3

What dogs tend to get mitral dysplasia?

Answer 3

• Young dogs
• Larger breeds

Congenital

Question 4

What breed are predisposed to myxomatous mitral valve disease?

Answer 4

• Cavalier King Charles Spaniel

Question 5

What is the gross pathology of MDVD?

Answer 5

• LA dilatation
• LV dilatation
• Elongation chordae tendinae
• Thickened leaflets
• Jet lesions

Question 6

What happens with valve leaks?

Answer 6

• Leakage of blood back into atria (left most likely)
• Reduction in forward stroke volume = blood leaving the heart
• Increase in volume of blood entering left ventricle in next diastole = volume overload

Question 7

What does neurohormonal activation cause on the sympathetic nervous system?

Answer 7

• Tachycardia
• Positive inotrope
• Vasoconstriction

Question 8

What does neurohormonal activation cause on the RAAS?

Answer 8

• Retention of Na + fluid
• Increased circulatory system
• Vasoconstriction

Question 9

What are sequalae of neurohormonal activation?

Answer 9

Sympathetic nervous system (tachycardia, vasoconstriction)
* Toxic for myocytes = intracellular Ca overload
* Increased oxygen demand
* Cell death, decrease in systolic function

RAAS
* Increased circulatory volume
* Increased hydrostatic pressures – congestion

Remodeling – eccentric hypertrophy
* Fibrosis (arrhythmias)
* Increased wall stress
* Dilatation of the valvular annulus = MR

Question 10

How do you stage MDVD?

Answer 10

• A = at risk
• B1 = murmur + no enlargement
• B2 = murmur + enlargement - Pimobendan
• C1 = CHF - hospitalised - FPAS (Furosemide, pimobendan, ACE/SPiro)
• C2 = CHF - at home
• D1 = refractory - hospitalised
• D2 = refractory - at home

Question 11

What is the most important thing to ask of consult?

Answer 11

• Exercise intolerance?
• Cough?
• Increased RR + effort?

Question 12

What should be done on exam?

Answer 12

• Auscultation - murmur
• Blood pressure
• Clinical pathology (NTProBNP)
• Radiography
• ECG
• Echocardiography

Question 13

What is troponin a marker for?

Answer 13

marker of myocyte damage

Question 14

What is the most important diagnostic imaging in practice?

Answer 14

• Radiography - DV + right lateral, cardiac size, pulmonary vessels, effusions

Question 15

If you can hear sinus arrhythmia what does this indicate?

Answer 15

• NOT in congestive heart failure

Question 16

What does normal vs MDVD hearts look like on echo

Answer 16

• bullet shaped ventricle + smaller square atrium
• Tennis ball ventricle + massive atrium

Question 17

What is the treatment of MDVD based on stages?

Answer 17

• A – none indicated, monitor at routine appointments
• B1 – none indicated, murmur will be present
• B2 – PIMOBENDAN
• C – CHF therapy as standard; Furosemide, pimobendan, ACEi, Spironolactone
• D – as for C with increasing doses and additional therapies e.g. sequential nephron blockade

Question 18

What other treatments are there?

Answer 18

Arrhythmias
* Supraventricular = Diltiazem, Digoxin
* Ventricular = Sotalol, Mexilitine

Pulmonary hypertension
* Sildenafil
* Pimobendan

Question 19

What is endocarditis?

Answer 19

• Infection of valve
• Mitral /aortic > tricuspid / pulmonic (In small animals)
• Staph, strep, E.coli, Pseudomonas

Question 20

What is the pathology of endocarditis?

Answer 20

• Bacteraemia
• Damaged endothelium
• Ability to adhere
• Hypercoagulable states

Question 21

What is diagnosed with echocardiography of endocarditis?

Answer 21

• Valvular vegetations
• Size = risk embolisation
• Regurgitation = MURMUR!
• Systolic dysfunction

Question 22

Tx of endocarditis?

Answer 22

• Antibiotics - minimum 6 weeks
• Anticoagulation - clopidogrel / aspirin
• long term valvular damage