Exam 4 - Canine DCM

Question 1

what is the most common canine cardiomyopathy?

Answer 1

DCM

Question 2

DCM is rare in dogs younger than ______ years

Answer 2

five

Question 3

what breeds are predisposed to DCM?

Answer 3

dobermans

large & giant breeds

Question 4

what is the pre-clinical stage of DCM?

Answer 4

stage B - relatively hard to diagnose

slow progression 1-2 years until CHF, but sudden death can occur in this stage

Question 5

what is the clinical stage of DCM?

Answer 5

stage C & D

congestive heart failure - left +/- right
sudden death from ventricular arrhythmias

Question 6

what is the pathophysiology of canine idiopathic DCM?

Answer 6

primary cardiomyopathy - genetic disease of the sarcomere

leads to severe ventricular systolic dysfunction with the LV more affected than the RV & secondary atrial/ventricular chamber dilation with the left side being more affected

Question 7

what is happening in the valves in canine DCM?

Answer 7

AV valves are normal in morphology but they can leak due to annular dilation - functional mitral regurgitation

Question 8

what is the most common cause of atrial fibrillation in the dog?

Answer 8

DCM

Question 9

what are the main causes of death in a dog with DCM?

Answer 9

clinically significant arrhythmias (ventricular or atrial fibrillation) causing weakness, collapse, or sudden death are relatively common

Question 10

what diagnostic test is most important to run in a dog you suspect has DCM?

Answer 10

chest rads - also response to treatment

bloodwork - evaluate kidney function, PCV/TS

Question 11

what are the stages of DCM as defined by ACVIM?

Answer 11

stage a - at risk
stage b1 - pre-clinical DCM with none-minimal structural heart disease
stage b2 - preclinical DCM with substantial structural heart disease
stage c - past or current signs or symptoms of heart failure
stage d - refractory heart failure

Question 12

what are some important diseases to consider that can mimic idiopathic DCM resulting in an echocardiographic DCM phenotype?

Answer 12

myocarditis (chagas), toxicity, arrhythmia induced, & diet associated DCM (taurine deficient or non-taurine deficient)

Question 13

what is diet-associated DCM?

Answer 13

associated with ‘BEG’ diets - boutique, exotic ingredients, & sometimes grain free

can affect dogs of any breed & age & can also lead to exacerbation of other heart diseases such as CVD & idiopathic DCM

Question 14

what absolute deficiencies can cause diet associated DCM?

Answer 14

choline, copper, l-carnitine, mg, thiamine, vitamin e, & selenium

Question 15

what are the current recommendations for preventing diet-associated DCM?

Answer 15

complete diet histories in all dogs & cats & recommend a diet change in those receiving suspect diets & increase vigilance for the detection of early warning signs of possible DA-DCM

Question 16

if you have a dog that has clinical warning signs of DCM that you have identified, what diagnostics should you do?

Answer 16

do an echo & check taurine levels in the blood - whole blood & plasma

recommend diet change after results - offer taurine supplementation if the echo shows any degree of systolic dysfunction or LV chamber dilation

Question 17

when should you recheck thiamine levels in a dog you suspect to have DA-DCM?

Answer 17

rechek the levels 3 months after the diet change & supplementation

Question 18

what are some findings on physical exam that may be supportive of potential DCM?

Answer 18

abnormal pulse or pulse deficits, any arrhythmia, gallop sounds, systolic murmur

subtle signs - history of mild exercise intolerance/syncope, increased respiratory rate or effort at home or in the clinic (home - > 30, clinic + > 40), & inappropriate/unintended weight loss