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39 Cards in this Set
- Front
- Back
Mitral valve apparatus comprises? |
-- valve leaflets -- chordae tendineae -- annulus fibrosis -- papillary muscles -- LA and LV walls |
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What are the four histologic layers of the leaftlet? |
-- atrialis -- spongiosa -- fibrosa -- ventricularis |
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Chronic degenerative valve disease pathophysiology (myxomatosis degeneration)? Which layers of the leaflet are the most affected? |
--degeneration of the fibrosa >> collagen and elastin dissolution/disorg. --thickened spongiosa >> hyaluronic acid, chondroitin sulfate accumulations --endothelial damage --hemorrhage, edema |
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Etiology of CDVD? Pathology of CDVD? |
--etiology: unknown, likely multifactorial >> genetic component --pathology: focal lesion >> multinodular lesion >> club-like leaflets that curl onto themselves worse at leaflet tips |
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CDVD is associated with prior infection or bacteremia. T/F? |
--false, it is NOT associated with prior infections or bacteremia. |
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CDCD progression? |
-- valve degeneration >> valvular insufficiency >> LA dilatation, LV eccentric hypertrophy >> annular dilatation, papillary misalignment >> more valve degeneration and insufficiency >> becomes vicious cycle |
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Determinants of regurgitant volume? |
1. regurgitant orifice area (size) 2. LV-LA pressure gradient 3. Duration of systole |
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Pathophysiology of regurgitation due to CDVD? |
-- decreased SV (some went back into LA) -- hypoperfusion -- inc. RAAS >> inc. blood vol. (preload) >> normalized SV >> worsened mitral regurgitation >> LV eccentric hypertrophy --inc. pulmonary capillary wedge pressure >> CHF (LHF) |
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Signalment of dogs with CDVD? |
--small breed >> min pins/schnauzers, chihuahuas, dachshunds --older age --male |
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History and physical exam findings in dogs with CDVD? |
-- cough, crackles -- tachypnea or dyspnea -- exercise intolerance -- left apical systolic murmur +/- systolic click -- +/- right side systolic murmur -- S3 gallop -- arrhythmias -- HR, inc. resp. rate and effort -- RHF (ascites, jug. distention, hepatomegaly) |
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ECG findings of dogs with CDVD may include? |
-- sinus rhythm or sinus tachycardia -- left atrial enlargement (wide P waves) -- atrial premature contractions (atrial stretch) -- atrial fibrillation -- LV enlargement -- LBBB |
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Three hallmarks of cardiogenic pulmonary edema? |
-- left atrial enlargement -- pulmonary venous distension -- interstitial or alveolar lung pattern |
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Radiographic monitoring of CDVD: what are you looking at? |
--vertebral heart score -- VHS increases slowly in early disease >> inc. markedly in later stages |
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Thoracic radiographs may show? |
-- trachea parallel to spine -- left atrial enlargement -- pulmonary venous distension -- interstitial/alveolar lung pattern >> pulmonary edema -- biventricular enlargement |
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Coughing in small breed male dog may also be due to? |
--respiratory disease, e.g. tracheal collapse |
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Echocardiography diagnosis of CDVD? |
--confirm suspected disease --quantify severeity of regurg. --assess LV and LA chamber sizes --assess LV function --estimate LA/pulmonary venous pressure --assess for concurrent diseases --must diagnose heart failure on radiographs |
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Treatment of CDVD? |
--treat acute HF >> furosemide, O2, nitroprusside, pimobendan |
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What does nitroprusside do? |
-- afterload reduction |
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What does pimobendan do? |
-- vasodilator -- + inotrope |
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Chronic therapy for decompensated CDVD? |
-- furosemide -- enalapril (ACE inhibitor) -- pimobendan |
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Understand the therapeutics used to treat mitral and tricuspid insufficiency (i.e. why is preload reduction beneficial? Why are ACEi indicated in heart failure?) |
ACE inhibitors reduce preload, which will decrease systolic dysfunction because you decrease the volume of blood that needs to be pumped (heart workload). |
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Prognosis of CDVD? |
-- progression of CDVD can be slow >> may have a murmur for years before development of CHF --once CHF develops, most dogs will live 1y >> with treatment >> shortened prognosis with complications |
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Complications of CDVD? |
-- atrial fibrillation -- ruptured chordae tendineae -- left atrial tear -- pulmonary hypertension |
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Pathogenesis of atrial fibrillation? Treatment? |
-- loss of atrial kick >> dec. CO -- therapy: digoxin +/- diltiazem |
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Pathogenesis of ruptured chordae tendineae? |
Massive increase in LA pressure >> inc. pressure in pulmonary vv. and capillaries -- sudden onset -- acute pulmonary edema -- acute dyspnea, collapse, cyanosis -- variable murmur -- sudden death |
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Treatment of ruptured chordae tendineae? |
-- nitroprusside >> afterload reduction >> reduce systemic pressure >> reduce pressure that LV must generate >> reduce pressure gradient between LA & LV >> dec. regurgitation |
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Left atrial tear outcomes? |
-- sudden death -- pericardial effusion and thrombus formation -- occurs with CDVD, chronic mitral regurgitation |
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Clinical signs of left atrial tear? |
-- collapse, ascites --weak pulse --diminished murmur --sudden death |
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Treatment for left atrial tear? |
--pericardiocentesis if tamponade --surgical closure (if continuing to bleed) --conservative medical management >> CHF, dec. atrial pressure |
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Signs of pulmonary hypertension? |
-- exercise intolerance -- collapse, ascites, syncope -- right apical murmur -- concurrent pulmonary disease |
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Treatment of pulmonary hypertension? |
-- Sildenafil, PDE5 inhibitor >> pulmonary arterial vasodilator |
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Anesthetizing CDVD patients? |
--benzodiazepines and opioids >> great in cardio patients --avoid alpha-2 agonists, ketamine --judicious fluid admin. --likely a better candidate earlier than later >> CDVD is progressive |
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Chronic degenerative valve disease (CDVD) is also known as? |
--endocardiosis --myxomatosis valvular degeneration (MVD) |
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What is the most common acquired heart disease of dogs? |
-- chronic degenerative valve disease |
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Acquired valve disease makes up ____% of canine cardiac disease. |
-- 75% |
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Distribution of CDVD lesions? |
-- mitral valve alone 62.0% -- mitral and tricuspid 32.5% -- mitral and aortic 2.5% -- tricuspid valve alone 1.5% |
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Genetic component breed associations of CDVD? |
-- Cavalier King Charles Spaniels -- Dachshunds |
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CDVD: endothelial damage may do what? |
-- activate and suppress substances involved in cell growth >> dysregulation ECM >> activated fibroblasts >> collagen growth location wrong |
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CDVD results in? |
-- increased valve thickness >> incompetence of valve >> insufficiency >> annular dilation >> R/L atrial dilation and eccentric hypertrophy of R/L ventricle |