DISEASES OF THE CARDIOVASCULAR SYSTEM ACQUIRED VALVULAR DISEASES

CHRONIC MITRAL VALVE INSUFFECIENCY SMALL BREED/TOY BREED DOGS, USUASLLY OLDER THAN 10 YEARS THE PREVALENCE OF THIS DISEASE INCREASES WITH AGE, AND IS PROGRESSIVE. IT ACCOUNTS FOR ~95% OF ALL HEART FAILURE CASES

CHRONIC MITRAL VALVE INSUFFICIENCY ONE OF THE MOST COMMON CAUSES IS CHRONIC PERIODONTAL DISEASE! BACTERIA THAT LIVE IN TARTAR, GET SHOWERED INTO THE BLOOD STREAM AND COLONIZE IN THE VALVE LEAFLETS.

CHRONIC MITRAL VALVE INSUFFICIENCY 1.Lungs: Pulmonary fibrosis, bronchitis, and chronic obstructive pulmonary disease. 2.Heart: Endocarditis, mitral valve regurgitation, and myocardial degeneration. 3.Liver: Hepatic parenchymal inflammation and hepatopathy. 4.Kidneys: Interstitial nephritis and glomerulonephritis. CHRONIC PERIODONTAL DISEASE CAN AFFECT SEVERAL ORGAN SYSTEMS

MITRAL VALVE INSUFFICIENCY THIS IS THE OPEN LEFT VENTRICLE SHOWING THE MITRAL VALVE LEAFLETS. WHAT ARE THE STRING-LIKE STRUCTURES THAT ATTACH THE VALVES TO THE PAPILLARY MUSCLES?

MITRAL VALVE INSUFFICIENCY CHORDAE TENDINEAE

MITRAL VALVE INSUFFICIENCY BOTTOM LEAFLET IS THICKENED AND NODULAR. THIS IS DUE TO INCREASED FIBROBLASTIC TISSUE WITHIN THE VALVE LEAFLETS TOP LEAFLET IS NORMAL

CHRONIC MITRAL VALVE INSUFFICIENCY DURING LEFT VENTRICULAR CONTRACTION, BLOOD FLOWS BACK INTO THE LEFT ATRIUM THE STIFF MALFORMED VALVE FAILS TO CLOSE SUFFICIENTLY DURING SYSTOLE.

MITRAL VALVE INSUFFICIENCY IF BLOOD CONTIUES THIS BACKWARD FLOW, THE ANIMAL MAY EXPERIENCE LEFT-SIDED HEART FAILURE CHARACTERIZED BY PULMONARY EDEMA

CHRONIC MITRAL VALVE INSUFFICIENCY DIAGNOSIS: – Radiographs – Echo – Systolic murmur at left apex; “whooping” quality There is no treatment to delay the onset of clinical signs. Treatment is aimed at improving symptoms of heart failure – Diuretics (lasix) – ACE inhibitor, vasodilator (Enalapril) – Diet change: low sodium

TRICUSPID VALVE INSUFFICIENCY

TRICUSPID INSUFFICIENCY RESULTS IN RIGHT-SIDED HEART FAILURE CHARACTERIZED BY PLEURAL EFFUSION

TRICUSPID VALVE INSUFFICIENCY RIGHT-SIDED HEART FAILURE ALSO LEADS TO ASCITES NOTE: THE LOSS OF ABDOMINAL DETAIL

TRICUSPID VALVE INSUFFICIENCY Treatment and client info are the same as for mtiral insufficiency; repeated abdominocentesis may be needed in these cases.

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DISEASES OF THE CARDIOVASCULAR SYSTEM HEARTWORM DISEASE

CANINE HEARTWORM DISEASE PARASITE CAUSING HEARTWORM DISEASE: DIROFILARIA IMMITIS MICROFILARIA OF D. IMMITIS ADULT HEARTWORMS

CANINE HEARTWORM DISEASE ONLY FEMALE MOSQUITOES BITE

DISTRIBUTION OF CANINE HEARTWORM DISEASE

CANINE HEARTWORM DISEASE ADULT HEARTWORMS LIVE IN THE PULMONARY ARTERIES. THE HEART MUST WORK EXTRA HARD TO PUMP AGAINST THIS OBSTRUCTION.

CANINE HEARTWORM DISEASE ADULT HEARTWORMS IN RIGHT VENTRICLE AND PULMONARY ARTERY

CANINE HEARTWORM DISEASE PREDOMINANT PATHOLOGY: DAMAGE TO THE PULMONARY ARTERY FROM ADULT HEARTWORMS – Endothelial damage and sloughing – Inflammation (leukocytes, platelets) Risk of thromboemboli – Pulmonary hypertension – Disruption of vascular integrity Thickened, fibrosed RIGHT VENTRICULAR HYPERTROPHY AND RIGHT- SIDED HEART FAILURE – The right ventricle compensates by dilating and increasing muscle thickness – Ultimately, there is decompensation and heart failure

CANINE HEARTWORM DISEASE Severe infection can lead to CAVAL SYNDROME – Worms back up into the right atrium and venae cavae Found in heavy worm burdens (>60) Associated with a poor prognosis Surgical treatment: pull worms from the right heart and venae cavae via jugular venotomy

CANINE HEARTWORM DISEASE

IDEXX SNAP TEST ADULT FEMALE ANTIGEN

CANINE HEARTWORM DISEASE

CANINE HEARTWORM DISEASE: PREVENTION HEARTGARD/IVERHEART – Ivermectin/pyrantel pamoate INTERCEPTOR/SENTINEL – Milbemycin oxime/ milbemycin oxime+lufeneron REVOLUTION – Selamectin ADVANTAGE MULTI/PROHEART 6 – Moxidectin – Q 6 month injectable TRIFEXIS – Moxidectin + spinosad

CANINE HEARTWORM DISEASE: TREATMENT STANDARD PROTOCOL: 1 epaxial injection, followed By a second injection on the opposite side 24 hours later ALTERNATIVE PROTOCOL: 1 Injection given followed in 4-6 weeks by 2 injections given 24 hours apart ONLY KILLS ADULT (L5) STAGE WORMS; DOXYCYCLINE IS REC. AS COMPLIMENTARY TX