What are the types of AV disease? (4)
- dysplasia of valve (malformation)
- degeneration (myxomatous, endocardiosis)
- infection (endocarditis)
- "functional"- ventricular remodeling (altered papillary muscles, ruptured chordeae tendineae, etc)
Describe valvular regurgitation.
valve is insufficient and leaks during systole--> systolic murmur, volume overload on affected side of heart--> eccentric hypertrophy and dilatation
Describe AV valvular stenosis.
obstruction to diastolic inflow--> diastolic murmur, marked dilation of atrium on affected side
Describe AV valvular dysplasia.
ANY part of the valve can be malformed (leaflets, chordeae tendineae, papillary muscles, annulus), and this can lead to regurgitation, stenosis, or both!
How is AV valvular dysplasia definitively diagnosed?
- PE: systolic murmur +/- arrhythmias (afib) with atrial dilatation
- echo/ post-mortem: abnormal leaflets, chords, or papillary muscles
With AV valve regurgitation, there is ____________ in the atrium.
systolic "V waves"
What species is DVD never reported in, ever?
cats and cows
What are some diseases that are responsible for heart failure in dogs? (9)
DVD, DCM, pericardial effusion, pulmonary hypertension (chronic MV regurg, heartworms, severe lung fibrosis), systemic hypertension, sustained primary arrhythmias, congenital heart diseases (PDA, SAS, PS, valve dysplasia), endocarditis, myocarditis
What is the etiology of DVD?
genetically predisposed--> adult onset
DVD is aka _______________; it has high prevalence in ___________ and usually affects the ___________.
endocardiosis, myxomatous valvular degeneration; small breed dogs; mitral valve
Gross lesions associated with DVD. (7)
leaflet thickening, +/- leaflet elongation/ redundancy (prolapse into atrium), smooth/ glistening endocardium, jet lesions, remodeling, arteriosclerosis, +/- rupture of chordeae tendineae
What are histologic lesions of DVD?
myxomatous change- deposition of acid-staining mucopolysaccharide (NOT inflammation)
Describe the pathophysiology of AV valvular regurgitation.
some of SV flows backwards--> EDV increases to activate F-S law--> increase preload, increase SV--> feed shunt AND maintain normal CO (compensated)--> eventually, volume overload and decompensation--> eccentric hypertrophy, L-CHF
______________ might help you to maintain systolic function in many dogs with DVD and mitral regurg.
Unloading the ventricle (ACEi +/- Amlodipine)
How can systemic hypertension complicate MV regurg?
inc BP--> inc afterload--> inc LV pressure--> backup through MV
Clinical findings with DVD. (9)
- [middle aged to older small breed dogs]
- clicks and systolic murmur
- coughing, tachypnea, exercise intolerance, +/- overt CHF, atrial arrhythmia (dilatated atrium), pulmonary hypertension
What is the most practical screening test for diagnosis of mild to moderate valvular disease of clinical relevance?
What are ECG changes associated with mitral regurg? Is this of value diagnostically? (3)
- NO DIAGNOSTIC VALUE if in normal sinus rhythm; it is valuable if the animal has a secondary arrhythmia
- wide/ tall P wave (dilated atrium), increased voltages (ventricular dilatation), secondary ST changes
What is the vertebral heart scale useful for?
- assessing cardiomegaly
- serial evaluations to predict risk for CHF
What is "flail leaflet"?
loss of support from ruptured chordae tendineae
__________ is an excellent and practical predictor of MR severity in chronic MR; in peracute MR, this metric ___________ severity.
LA size on radiography (or echo); underestimates
Do serial echos help in the long-term management of DVD?
No you can prognosticate with radiographs (evaluate for CHF)
What is a commonly confusing finding on echo with DVD in small dogs?
hyperdynamic LV due to increased preload and decreased afterload, even in heart failure (don't rule out heart failure because the ejection fraction is normal or high)
PE findings w/ L-CHF. (6)
tachypnea, +/- cough, murmur or gallop, tachycardia, +/- afib, +/- crackles
What biomarker is supportive of L-CHF?
What imaging findings are supportive of L-CHF? (4)
- thoracic US: B lines/ rockets
- thoracic radiography is confirmatory: cardiomegaly (esp LA), pulmonary vascular prominence, pulmonary parenchymal density
What are "trends" in sleeping respiratory rate in dogs with L-CHF?
- <25/min + for L-CHF
- >35/min - for L-CHF
What are differential diagnoses of coughing in mitral regurg? (7)
- cardiac: left main bronchus compression (dilated LA), unapparent PE
- large airway disease: laryngeal paralysis, tracheal collapse, bronchomalacia
- bronchopulmonary disease: chronic bronchitis, lung disease
What are clinical signs of chronic MV regurg with pulmonary hypertension? (4)
loud tricuspid regurg, ascites, exertional collapse or syncope (back up to right heart when becomes chronic)
How is chronic MV regurg with pulmonary hypertension diagnosed?
high velocity tricuspid regurg jet onCW Doppler echo
What is indicated in the therapy for chronic MV regurg with pulmonary hypertension?
Sildenafil (PDE V inhibitor)
What is the hospital therapy for acute CHF?
- FONS Plus
- Pimobendan (dogs)
What drug is indicated in cardiogenic shock?
What is the standard medical therapy for chronic CHF stages C and D?
- Na+ restricted diet
- Enalapril (ACEi)
- Furosemide oral
What are potential causes of mitral regurgitation in dogs? (7)
DVD, DCM, valvular dysplasia, systemic hypertension, endocarditis, persistent atrial standstill (atrial CM), aortic regurg/ stenosis (secondary to volume overload)
What are potential causes of tricuspid regurg in dogs? (4)
ARVC, pulmonic stenosis, pulmonary hypertension, +/- atrial CM
What are the most common causes of mitral regurg in cats? (3) In horses? (2)
- Cats: HCM, taurine-associated DCM, systemic hypertension
- Horses: rupture of chordae tendineae, (young horse consider valve dysplasia)