Mitral Valve disease Flashcards by Hannah Leech

Outline what MMVD is

Can be considered age related change, occurs too early in Cavvies
Inherited (not simple) in CKCS and dachshunds
All heart valves may be affected
Degeneration of the vavlve leads to LA and LV overload, LV dilation and eccentric hypertrophy
Normally LV systolic function remains OK or is hyperdynamic - although can get systolic issues in large dogs
As LHS pressures increase, get L CHF

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What type of murmur do you get in MMVD?

Left apical early (proto-)systolic
becoming holo-or pan-systolic, “plateau” shaped
heart murmur.
Can be musical

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What do pan and holosystolic mean?

Pan - over both heart sounds

Holo - in between 1st and second heart sounds

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What does a cough mean in MMVD?

NOT CHF
LA enlargement
Possible concurrent airway dz

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What do you see in CHF in dogs with MMVD?

Increase RR and dyspnoea - therefore get a baseline so you now when things are increasing

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What does a wheezy cough suggest?

Concurrent bronchomalacia

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What do diastolic gallops suggest?

Heart disease (not common though)

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What Ix can you do for dogs with expected MMVD?

Echo
Rads
Bloods (assess for other dz and prior to diuresis)
Biomarkers
BP (systemic hypertension increases progression of disease)

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What do Pro BNP values over 1500 and 1800 suggest?

1500 - Increased risk CHF over next 12 months

1800 - consistent with CHF

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How do you asses for MV prolapse on echo?

Draw a line across the anulus - if the MV projects across you have prolapse

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What are the signs of LA enlargement echo?

Right parasternal 4 chamber view - bowing of intercranial septum to the R
Right parasternal short axis view (mercedes benz signs) - LA:Ao ratio should be less than 1.6

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What types of arrhythmias can occur with MVD?

supraventricular premature complexes
Atrial fibrillation (more large breeds)

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What is the normal CKCS VHS less than?

11.7 (normal is 10.7)

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What is the cornnell formula?

Allows scaling of M-mode measurements to understand what is normal based on dog’s body weight

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What are the requirements to be in B2?

Murmur 3/6 or greater
No c/s apart from mild cough
LA dilation
LV dilation in diastole >1.7
VHS >10.5

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What did the Epic study show?

Giving pimobendan to stage B2 patients increases symptomatic period by 15m

What is the ideal immediate acute CHF treatment?

IV frusemide 1-2mg/kg initally, then 1mg/kg every 1-2 hours until RR < 55
May involve giving dose totally >20mg/kg/day
Monitor urea and crea initially and after 24 hours

What can be an issue with frusemide boluses?

Can lead to rebound RAAS activation

Some will use CRIs although these may have a higher risk of azotaemia and dehydration

How and when can you start frusemide as an outpatient treatment?

Oral start if not dyspnoic
Monitor renal function after 7d
Count RRR at home to titrate

Why should you not use frusemide on its own?

Leads to RAAS activation

What are the bad effects of congestive heart failure due to sympathetic stimuation and RAAS activation?

Vasoconstriction
Increased HR
Myocardial remodelling/ fibrosis
Oedema/ effusions

Why is Angiotensin II the main bad guy with CHF?

Leads to remodelling, Na and H20 retention and vasopressin release

What is the use of ACEi in CHF?

Leads to improved survival, QoL, haemodynamic parameters

When should ACEi be avoided in CHF patients?

Patients with low BP needing high doses of frusemide

Is for chronic use, not needed when dealing with acute episode

Outline pimobendan

Is a Ca sensitiser - +ve inotrope Is a phosphodiesterase inhibitor - +ve inotrope and vasodilator Main benefit in MMVD = arteriodilation, Increase in forward stroke volume and decrease in regurgitant stroke volume Reduces LA pressure and cardiac size

Outline the use of spironolactone

Aldosterone antagonist K+ sparing diuretic Counteracts remodelling

Should quadruple therapy be used for CHF?

Logic suggests yes but no concrete evidence for it

What should you do in stage D patients?

Ensure optimum dose of pimobendan and other drugs Some will suggest TID pimobendan BID ACEi If RCHF and gut oedema, give parenteral drugs Ensure giving spironolactone as reduces risk of frusemide resistance Consider changing to torasemide Consider sequential nephron blockage - hydrochlorothiazide/ amiloride Consider further afterload reduction with amlodipine/ similar if BP OK identify and tx arrhythmias identify and tx pulmonary hypertension

When is increasing frusemide unlikely to be effective

Once passed 3mg/kg TID

Outline the use of torasemide

Approx 20x as potent as frusemide so when changing cut the frusemide dose by 20 V high risk AKI - monitor renal values and lytes 2d and 7d post use and any change in dose

Outline pulmonary hypertension

May have loud tricuspid regurge murmur Likely to have exercise intolerance/ collapse on exertion May be d/t increased LA pressure, which is transmitted across the pulmonary vasculature to result in pulmonary arterial hypertension Pulmonary artery systolic pressure can be estimated from the tricuspid regurge velocity in the absence of pulmonary stenosis

How do you treat ruptured chordae tendinae

If minor - may only see mild increase in CHF Tx wih vigorous afterload reduction If a primary cord is ruptured, is likely to be a terminal event

What occurs in a LA tear?

Pericardial h+ Cardiac tamponade Diastolic collapse of RA

When would you suspect a LA tear?

Presents collapsed, hypotensive, muffled heart sounds, quieter heart murmur See pericardial effusion with large LA on scan

How do you treat a LA tear?

Give drugs to reduced LA pressure - nitroprusside, amlodipine, hydralazine If needed, support preload with cautious use of fluids Increase frusemide dose Avoid pericardiocentesis If can get over the first week, can do well

What is the MST once the pet is in heart failure?

Less than a year

What are good/ bad prognostic indicators for MST once in CHF?

Good - being a CKCS, higher creatinine, lower frusemide dose needed Bad - exercise intolerance, larger VHS, greater LA:Ao ratio