Acquired Cardiac Disease: Valvular Heart Disease

What is another term for degenerative valvular disease?

endocardiosis, myxomatous degeneration, mitral valve disease

What is the most common form of acquired cardiac disease in dogs?

degenerative valvular disease

What is degenerative valvular disease (endocardiosis)?

non-inflammatory myxomatous degeneration; collagen disorder with fibroelastic tissue replacement

What is the most common valve affected with degenerative valvular disease?

chordae tendineae of mitral followed by tricuspid, aortic then pulmonic

What breeds are at increased risk to develop degenerative valvular disease?

chondrodystrophic

What is the anterior leaflet of the mitral valve?

septal

What is the posterior leaflet of the mitral valve?

mural

What are the 4 layers of the mitral valve?

atrialis, fibrosa, spongiosa, ventricularis

What is the function of the mitral valve?

allows blood to flow from the left atrium to the left ventricle during diastole and prevents blood from flowing backward into the atrium during systole

True or False: mitral valve is closed during diastole and open during systole.

False: mitral valve is open during diastole and closed during systole. Semilunar valves are closed during diastole and open during systole.

What is mitral valve leakage?

leakage of blood from the ventricle through the mitral valve into the atrium during systole, turbulent blood flow (leakage) causes a systolic heart murmur; mitral valve regurgitation

What are the causes of mitral valve regurgitation?

abnormalities of the valve leaflets, chordae tendineae, papillary muscles, or valve annulus dilation

What is the most common cause of mitral valve regurgitation in dogs?

chronic degenerative valve disease (abnormalities of valve leaflets)

What are examples of abnormalities of the valve leaflets?

CDVD, dysplasia (congenital malformation), bacterial endocarditis

What are examples of abnormalities of the chordae tendineae?

CDVD, dysplasia

What are examples of abnormalities of the papillary muscles?

malorientation, dysplasia

What are examples of valve annulus dilation?

ventricular dilation (volume overload diseases)

What are degenerative lesions?

thickening of the valve leaflets, nodular thickening of the leaflet margins, weakening and lengthening of the chordae tendineae

What are the odds that you see degenerative lesions of the mitral valve alone?

60%

What are the odds that you see degenerative lesions of the tricuspid valve alone?

10%

What are the odds that you see degenerative lesions on both the mitral and tricuspid valves?

30%

What is the pathophysiology of endocardiosis?

reduced forward stroke volume results in Na+/H2O retention, volume overload of the heart

What is decompensation of stable CDVD patient?

arrhythmia, chordal rupture, LA tear, and high-salt meal

What can you hear on physical exam auscultation with a mitral valve prolapse? 1st step of progression of mitral valve disease.

systolic click; may or may not hear a murmur with mild regurg but definetly will hear one with moderate and severe regurgitation

What is the end-result of severe CDVD?

LCHF; pulmonary edema secondary to high left atrial pressures

Endocardiosis can lead to enlargement of the left atrium and ventricle. What will be seen on ECG?

wide notched P waves (LAE) and tall R waves (LVE)

What are the possible arrhythmias seen on ECG of endocardiosis patient?

sinus tachycardia, atrial premature contractions, atrial fibrillation

What are the common findings on radiographs of an endocardiosis patient?

tracheal elevation with splitting of mainstem bronchi, compression of L mainstem bronchus from dilated LA, and pulmonary venous congestion/pulmonary edema

What vertebral left atrial score is suggestive of left atrial enlargement?

>2.3

What provides definitive diagnosis, severity, and prognosis of endocardiosis?

echocardiogram

What is M-mode echocardiography?

“ice-pick” view of the heart with narrow beam imaged over time, excellent spatial resolution good for recording “normal values”

What is the % fractional shortening equation?

(LVDd - LVDs) / LVDd x 100

What is LVPWs and LVPWd?

left ventricular posterior wall in systole and diastole

What is IVSs and IVSd?

interventricular septum in systole and diastole

What is LVIDs and LVIDd (LVDs, LVDd)?

left ventricular diameter in systole and diastole

What is used to determine staging of mitral valve disease?

LVIDd index dependent on body weight in kgs

What is fraction of shortening?

indicated how much smaller (as a percentage) the left ventricular internal diameter is in systole compared to diastole; estimation of systolic function

What is the normal range of fraction of shortening?

25-35%

What happens to the %FS with endocardiosis?

increases due to regurgitant volume; <40% with severe MR suggests myocardial disease

What can be seen in clinical pathology with endocardiosis?

pre-renal azotemia; decreased Na+, K+, and Cl- is severe or with diuretics

What is the diagnostic biomaker for endocardiosis?

NT-ProBNP test

What is the NT-ProBNP test?

does NOT confirm diagnosis but normal levels rule out severe CDVD; Dr. Green DOES NOT recommend for endocardiosis, do rads instead

What is a class A patient with chronic valve disease?

indicates high risk patient but no current structural disease; “bossum clutchers”; excellent prognosis

What is a class B patient with chronic valve disease?

asymptomatic patient with structural heart disease; good prognosis

Is the the B1 stage of chronic valve disease?

no to mild radiographic or echocardiographic changes

Is the the B2 stage of chronic valve disease?

significant evidence of structural change (specific criteria)

What is the specific criteria for a patient in B2 stage chronic valve disease?

>III/VI murmur intensity, LA:AO ratio >1.6 and LVDd >1.7, VHS>11 and VLAS >3

What is a class C patient with chronic valve disease?

past or current clinical signs of heart failure associated with structural heart disease; acute or chronic; guarded to poor prognosis

What is a class D patient with chronic valve disease?

end-stage refractory to standard therapy; acute or chronic; poor to grave prognosis

What is infectious endocarditis?

inflammatory destructive lesion of valve, endothelial damage with fibrin deposition (bacteremia/fungemia) can be an immune-mediated inflammatory process or toxin production (some collagenolytic), vegetation induces valvular dysfunction

What are the risk factors for infectious endocarditis?

pre-existing valvular damage (congenital cardiac disease;SAS - endocardiosis is not a risk factor) and source of bacteremia (open wound, surgical sites, genitourinary tract)

What are the valves involved with endocarditis?

mitral and aortic, mural endocarditis (posterior lining)

What is the pathophysiology of infectious endocarditis?

vegetative lesion: fibrin, inflammatory cells, organisms; protects organisms from host defense mechanisms, myocardial abscesses, and aortic sinus rupture/fistulae

What are the clinical findings with infectious endocarditis?

large male breeds most likely systemically ill, febrile, lethargic, shocky, with cough, dyspnea, exercise intolerance, swollen hot painful joints (septic arthritis), CNS signs (septic meningoencephalitis), syncopal episodes from arrhythmias (Vtach, AV block)

What can be heard on cardiac auscultation with infectious endocarditis?

depends on valve involved but crackles/wheezes if pulmonary edema/pulmonary abscesses, S3 gallop, systolic murmur with mitral valve and diastolic murmur with aortic

What is the diagnostic of choice for infectious endocarditis?

echocardiography

What diagnostic test is needed to identify the bacteria causing infectious endocarditis?

blood cultures, surgical prep and aseptic technique collect 3-5 samples (aerobic and anaerobic) from different sites; ideally want 2 positive cultures of same organisms

What are the most common organisms that cause infectious endocarditis?

corynebacterium spp., streptococcus spp., staphylococcus spp.

What can you do if the owner has money concerns or you could only obtain a small blood volume from your patient when determining the cause of infectious endocarditis?

urinary culture could document organism is same as septic organism but does not replace a blood culture

What is the prognosis for infectious endocarditis?

overall poor, variable with mitral valve but grave to poor with aortic valve (>80% are dead within 2 weeks)