Here's why it's unlikely:
* Blitzen's association with Santa: The name "Blitzen" is most famously associated with one of Santa Claus' reindeer. This association would make it an unusual name for a racehorse.
* Harness Racing History: Harness racing has a long and rich history, and while there have been many great horses with unique names, a horse named "Blitzen" with significant racing achievements doesn't appear in the records.
It's possible there could be a lesser-known horse with that name, but it's not a name that stands out in the history of harness racing.