Canine Top Cardiac Diseases - Part 1

Question 1

what dog breeds are most commonly affected by DCM?

Answer 1

large/giant breeds: dobermans, boxers, great danes, irish wolfhounds, standard poodles, & cocker spaniels

Question 2

what are the early signs of DCM?

Answer 2

middle-aged dog with a heart murmur, weak peripheral pulses, & exercise intolerane

Question 3

what are the signs of CHF in a dog with DCM?

Answer 3

cough, tachypnea, dyspnea, tachycardia, & weakness

Question 4

what is seen on thoracic rads that is supportive of DCM?

Answer 4

generalized cardiomegaly, variable venous dilation, & pulmonary edema/perihilar infiltrate if decompensating

Question 5

what changes are seen on an echo in a dog with DCM?

Answer 5

left atrial/ventricular enlargement, mitral +/- tricuspid valve regurgitation, +/- right atrial/ventricular dilation, evidence of poor contractility (prolonged end-point separation & decreased fractional shortening)

Question 6

what is seen on ECG/holter monitor on a dog with DCM?

Answer 6

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

Question 7

what treatment is used for a dog with DCM prior to the onset of CHF?

Answer 7

ACE inhibitors, pimobendan (positive inotrope & vasodilator) if heart dilation is present, & anti-arrhythmics (sotalol/mexiletine) if indicated

Question 8

what treatment is used for a dog with DCM with the acute onset of CHF?

Answer 8

oxygen, stress reduction, parenteral furosmide, & pimobendan

Question 9

what chronic therapy is used for a dog with DCM?

Answer 9

oral furosemide, ACE inhibitors, & pimobendan

Question 10

T/F: dogs can die without any signs of disease with DCM from arrhythmias

Answer 10

TRUE

Question 11

how does pimobendan affect the prognosis of DCM?

Answer 11

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

Question 12

what are some of the causes of DCM?

Answer 12

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

Question 13

what is the feline breed predilection of DCM?

Answer 13

siamese, burmese, & abyssinian

Question 14

why is prognosis usually poor for cats with DCM?

Answer 14

usually poor because they typically present in CHF

Question 15

what is cardiac tamponade?

Answer 15

flailing right heart due to pressure from the pericardial effusion

Question 16

what is the classic case presentation of pericardial effusion in dogs?

Answer 16

acute onset on weakness/collapse, exercise intolerance, abdominal distension, muffled heart sounds, tachycardia, weak femoral pulses, jugular pulses, & pulsus paradoxus

Question 17

what is the etiology of pericardial effusion?

Answer 17

cardiac tumors - german shepherds, goldens, labs, bulldogs, bostons & idiopathic - goldens & labs

Question 18

what is seen on ECG of a dog with pericardial effusion?

Answer 18

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

Question 19

what is seen on radiographs of a dog with pericardial effusion?

Answer 19

rounded, globoid silhouette, dilated caudal vena cava, & ascites due to passive congestion

Question 20

what is seen on ECHO in a dog with pericardial effusion?

Answer 20

fluid-filled sac surrounding the heart - possibly a causative mass in the right atrium, right auricle, or at the heart base

Question 21

what is seen on cytology from pericardial effusion? how do you improve the diagnostic yield?

Answer 21

unless due to infection or lymphoma, rarely of diagnostic value - effusion of PCV less than 10% appears to improve diagnostic yield

Question 22

how is pericardial effusion treated with pericardiocentesis?

Answer 22

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

Question 23

how is pericardial effusion treated with a pericardectomy?

Answer 23

for recurrent effusions & to decrease the risk of tamponade - also can be curative for idiopathc pericarial effusion

Question 24

how is pericardial effusion due to neoplasia treated?

Answer 24

right auricle hemangiosarcoma - possible surgical resection & chemotherapy for - lymphoma, chemodectoma, hemangiosarcoma, & mesothelioma

Question 25

what is the prognosis of pericardial effusion due to hemangiosarcoma/mesothelioma?

Answer 25

poor long-term - recurrent effusions & metastatic disease are the most common cause of death

Question 26

what is the prognosis of pericardial effusion due to a chemodectoma?

Answer 26

guarded long term prognosis - pericardectomy can prolong survival if pericardial effusion is recurrent

Question 27

pericardial effusion in cats is usually due to what?

Answer 27

manifestation of heart failure

Question 28

T/F: for pericardial effusion, ultrasound is diagnostic & can identify underlying etiology such as a tumor

Answer 28

TRUE

Question 29

what is the prognosis for pericardial effusion due to an idiopathic cause?

Answer 29

good if effusion rarely reoccurs or if pericardectomy can be pursued

Question 30

what is pulsus paradoxus?

Answer 30

increase in pulse pressure during expiration & decrease during inspiration (normally occurs, but not as easily palpable when compared to pericardial effusion)

Question 31

what is the classic case presentation of a dog with HWD?

Answer 31

exercise intolerance, cough, dyspnea, & abdominal distension

Question 32

what clinical case presentation is seen in a dog with caval syndrome due to HWD?

Answer 32

acute onset of lethargy/weakness - coffee-colored urine due to hemoglobinuria

Question 33

what is the etiology of HWD?

Answer 33

dirofilaria immitis

Question 34

what is the classic case presentation of heartworm disease in cats?

Answer 34

vomiting, intermittent cough, increased respiratory rate, & acute death

Question 35

what are potential causes of false negative test results for heartworms?

Answer 35

antigen-antibody complex formation, immature females in an early infection, light infection, or a male only infection

Question 36

how is HWD diagnosed?

Answer 36

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

Question 37

what is seen on radiographs of a dog with HWD?

Answer 37

enlarged, tortuous, blunt ending pulmonary arteries, right heart enlargement, & pulmonary parenchymal disease

Question 38

how is HWD diagnosed in cats? why is it challenging?

Answer 38

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

Question 39

what treatment is used for HWD prior to starting adulticide?

Answer 39

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)

Question 40

what is the adulticide therapy used for HWD?

Answer 40

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

Question 41

what is the purpose of treating a HW positive dog with steroids?

Answer 41

controls signs of pulmonary thromboembolism

Question 42

when is surgery recommended for HWD dogs?

Answer 42

caval syndrome

Question 43

what is the prognosis of feline heartworm disease? how is it treated?

Answer 43

guarded to fair - no melarsomine!!! prednisolone to help with lung changes