Acquired Valvular Diseases Flashcards
What is the most common cardiac disease in dogs, and what are the synonyms?
Myxamatous mitral valve disease MMVD
Mitral valve disease
Vlavular endocardosis and endocardiosis
Chronic valvular disease
Degen valvular disease
Incidence of MMVD
3.5% could be 70-90% in certain breeds older than 8 wks!
Small (Bischon, KC, poodle)
Males>females
MV> MV/TV>>> TV
** usually only the mitral valve
Pathomechanism of MMVD
Interstitial cells- active phenotype– remodelling of the ECM– affects the structural aspect of the valve leaflets. These intersitial cells can be activated by both serotonin and TGF-beta
Dominant signalling pathway:TGF-beta
Associated withSEROTONIN: incr serum serotonin, number of receptors, autocrine prod in the leaflets, downreg of clearance
ECM expands: glycosaminoglycans and proteoglycans, loss of the collagenous fibrous layer
—-> malform, mechanical dysfunction and mitral incompetence
Morph changes associated with MMVD
Nodules, thickening, distorted edges of leaflets- now cannot close properly
Ruptured chordae tendinae
Pap muscles
Dilated mitral ring that now collapses backwards
Clinical consequnces of the morph changes
Mitral valve prolapse
Mitral insufficiency
Vol overload- eccebtric hypertrophy of LA and LV …
Incr P in the LA and pulm vein– pulm edema– pulm hyperT
Diagnosis of MMVD
Left apical systolic heart murmur- puncta maxima near the apex of the heart! 3-5 ICS close to the sternum!
Signs of L (and maybe R) sided HF
Treatment of MMVD when in B1 or B2 stage acc to ACVIM
Pimobendan only known effective drug (for B2)
Requires a dilated heart in order to work, prolomgs the subclinical phase of the disease
Not recommended to use:
ACE-1
Spironolactone
Beta-blockers
Treatment of MMVD when in C and D of ACVIM
** danger of L atrium rupturing due to the v high P
Give CHF treatment- furosemide and Pimobendan
Complications: pulm hyerpT- treat with sildenafil
Supraventric arrhythmia
Left atrial tear- tamponade
ENDOCARDITIS
Rare
Large breed dogs
BACT caused: bacteraemia– septicaemia
Staph, strep, e.coli, bartonella
Predisp: aortic stenosis/congenital heart disease
Thrombus/embolus formation– infarcts– necrosis
Complications: CHF, immune diseases, thromboembolism
Clinical Signs of Endocarditis
Fever (joint problems)
Back pain, polyarthritis, muscle embolism– reluctance to move/ intermittent lameness
HF
Rarely syncope/weakness- would be due to an AV block!
Bradyarrhyth secondary due to infection
Diagnosis of Endocarditis
Sudden appearance of murmur
Fever
L shift of WBC’s
APP: CRP in dogs and SAA in cats
Thickening of aortic/mitral valve
Haemoculture: be aware bartonella doesn’t show
PCR
Treatment of Endocarditis
Broad spec AB’s first IV… then PO
Later can choose AB’s based on the culture
Treat HF
Antithrombosis: Clopidogrel, Heparin, Aspirin
