What would be required for the OFA database to include a category of affected dogs from TVD? Right now there is no way to search this, only to search an abnormal cardiac result, but not specifically TVD.

You would need parent club and OFA agreeing to do this. That being said, it probably makes no difference due to lack of reporting of affecteds. I came up with just TWO abnormals searching the breed for the last 5 years.