Sonopath Forum

  • 19 month old female Boxer Dog with mild lethargy
  • Had mild sedation butorphanol/dexdomitor for abdominal scan that was reversed 1 hour prior to cardiac scan
  • Mild right sided dilation and tricuspid regurgitation
  • Is this tricuspid valve dysplasia or ARVC or other?
  • What age does ARVC typically develop



ARVC usually develops at


ARVC usually develops at an age of 5-7 years. It is mainly characterised by ventricular arrhythmia with a left bundle branch block morphology (upright in lead II). So, to rule it out, at least one, and if negative, a second Holter recording would be required. Some of these dogs develop heart failure, and some show just signs of right heart enlargement/dysfunction. However, these dogs are usually symptomatic.

In your videos, I cannot see major changes of the tricuspid valve. Also, the TI is rather subtle here. I agree that the right heart seems to be a bit enlarged. However, the dog shows substantial (likely respiratory) arrhythmia, which can lead to major differences in right heart preload, particulary in brachycephalic dogs.

Summarizing, if you want to rule out ARVC, you might want to do a Holter recording. Striatin mutaion testing can be of some value, but is likely not as useful as Holter monitoring due to variable penetrance and exspressivity. Less than 20 VPCs rule out ARVC at the time of recording.

I can’t see enough TI here to cause right heart enlargement. 


Best regards



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