Canine Top Cardiac Diseases - Part 1 Flashcards
what dog breeds are most commonly affected by DCM?
large/giant breeds: dobermans, boxers, great danes, irish wolfhounds, standard poodles, & cocker spaniels
what are the early signs of DCM?
middle-aged dog with a heart murmur, weak peripheral pulses, & exercise intolerane
what are the signs of CHF in a dog with DCM?
cough, tachypnea, dyspnea, tachycardia, & weakness
what is seen on thoracic rads that is supportive of DCM?
generalized cardiomegaly, variable venous dilation, & pulmonary edema/perihilar infiltrate if decompensating
what changes are seen on an echo in a dog with DCM?
left atrial/ventricular enlargement, mitral +/- tricuspid valve regurgitation, +/- right atrial/ventricular dilation, evidence of poor contractility (prolonged end-point separation & decreased fractional shortening)
what is seen on ECG/holter monitor on a dog with DCM?
ventricular ectopic beats, may see significant ventricular arrhythmias early in dobermans, a fib in advanced disease, holter monitoring to evaluate the severity of the arrhytmia & if therapy is indicated
what treatment is used for a dog with DCM prior to the onset of CHF?
ACE inhibitors, pimobendan (positive inotrope & vasodilator) if heart dilation is present, & anti-arrhythmics (sotalol/mexiletine) if indicated
what treatment is used for a dog with DCM with the acute onset of CHF?
oxygen, stress reduction, parenteral furosmide, & pimobendan
what chronic therapy is used for a dog with DCM?
oral furosemide, ACE inhibitors, & pimobendan
T/F: dogs can die without any signs of disease with DCM from arrhythmias
TRUE
how does pimobendan affect the prognosis of DCM?
if started prior to the onset of CHF, will delay the development of CHF - can extend life during CHF but prognosis after 1 year is poor
what are some of the causes of DCM?
taurine-deficiency-linked in american cocker spaniels, goldens, boxers, & dalmatians, carnitine-responsive DCM in boxers, chagas disease (trypansoma cruzi), parvovirus exposure in utero, & doxorubicin induced
what is the feline breed predilection of DCM?
siamese, burmese, & abyssinian
why is prognosis usually poor for cats with DCM?
usually poor because they typically present in CHF
what is cardiac tamponade?
flailing right heart due to pressure from the pericardial effusion
what is the classic case presentation of pericardial effusion in dogs?
acute onset on weakness/collapse, exercise intolerance, abdominal distension, muffled heart sounds, tachycardia, weak femoral pulses, jugular pulses, & pulsus paradoxus
what is the etiology of pericardial effusion?
cardiac tumors - german shepherds, goldens, labs, bulldogs, bostons & idiopathic - goldens & labs
what is seen on ECG of a dog with pericardial effusion?
tachycardia, electrical alternans (beat to beat alternating height of r-wave amplitude due to the swinging motion of the heart within the fluid filled sac) that occurs in 50% of cases, & low r wave amplitude
what is seen on radiographs of a dog with pericardial effusion?
rounded, globoid silhouette, dilated caudal vena cava, & ascites due to passive congestion
what is seen on ECHO in a dog with pericardial effusion?
fluid-filled sac surrounding the heart - possibly a causative mass in the right atrium, right auricle, or at the heart base
what is seen on cytology from pericardial effusion? how do you improve the diagnostic yield?
unless due to infection or lymphoma, rarely of diagnostic value - effusion of PCV less than 10% appears to improve diagnostic yield
how is pericardial effusion treated with pericardiocentesis?
ultrasound guided using a closed collection system - typically on the right between the 4th & 6th ribs at the costochondral junction making sure to record an ECG during the procedure as rrhythmias will happen if the needle touches the heart
how is pericardial effusion treated with a pericardectomy?
for recurrent effusions & to decrease the risk of tamponade - also can be curative for idiopathc pericarial effusion
how is pericardial effusion due to neoplasia treated?
right auricle hemangiosarcoma - possible surgical resection & chemotherapy for - lymphoma, chemodectoma, hemangiosarcoma, & mesothelioma
what is the prognosis of pericardial effusion due to hemangiosarcoma/mesothelioma?
poor long-term - recurrent effusions & metastatic disease are the most common cause of death
what is the prognosis of pericardial effusion due to a chemodectoma?
guarded long term prognosis - pericardectomy can prolong survival if pericardial effusion is recurrent
pericardial effusion in cats is usually due to what?
manifestation of heart failure
T/F: for pericardial effusion, ultrasound is diagnostic & can identify underlying etiology such as a tumor
TRUE
what is the prognosis for pericardial effusion due to an idiopathic cause?
good if effusion rarely reoccurs or if pericardectomy can be pursued
what is pulsus paradoxus?
increase in pulse pressure during expiration & decrease during inspiration (normally occurs, but not as easily palpable when compared to pericardial effusion)
what is the classic case presentation of a dog with HWD?
exercise intolerance, cough, dyspnea, & abdominal distension
what clinical case presentation is seen in a dog with caval syndrome due to HWD?
acute onset of lethargy/weakness - coffee-colored urine due to hemoglobinuria
what is the etiology of HWD?
dirofilaria immitis
what is the classic case presentation of heartworm disease in cats?
vomiting, intermittent cough, increased respiratory rate, & acute death
what are potential causes of false negative test results for heartworms?
antigen-antibody complex formation, immature females in an early infection, light infection, or a male only infection
how is HWD diagnosed?
heartworm antigen snap test to detect proteins secreted by the female worms - earliest to detect is at 5 months post-infection & microfilaria tests - both recommended yearly
what is seen on radiographs of a dog with HWD?
enlarged, tortuous, blunt ending pulmonary arteries, right heart enlargement, & pulmonary parenchymal disease
how is HWD diagnosed in cats? why is it challenging?
rads - only 50% will have changes seen, antigen testing, antibody testing, & ultrasound to maybe see a worm in the main pulmonary artery - cats have a lower worm burder, so harder to diagnose
what treatment is used for HWD prior to starting adulticide?
doxycycline started 30 days prior for wolbachia & macrocyclic lactones/heartworm preventatives 2 months prior to adulticide to prevent new injections, eliminate susceptible larvae/microfilaria, & allows for the immature worms to mature to a stage more susceptible to adulticide (pretreating with diphenhydramine & steroids if microfilaria positive to prevent anaphylaxis secondary to rapid die off)
what is the adulticide therapy used for HWD?
melarsomine dihydrochloride - 1 injection IM, then one month later, 2 injections back to back 24 hours apart with strict exercise restriction starting with the first dose & then 6-8 weeks after the last dose
what is the purpose of treating a HW positive dog with steroids?
controls signs of pulmonary thromboembolism
when is surgery recommended for HWD dogs?
caval syndrome
what is the prognosis of feline heartworm disease? how is it treated?
guarded to fair - no melarsomine!!! prednisolone to help with lung changes
