I thought a form of seizure, also....However, the more I think about it, I'm wondering about a Heart Defect.....Either way, your Vet needs to get to the bottom of it before they get worse......Please come back and let us know what you find out.....I'd be interested in knowing.....Good luck, Karla
I may be wrong here, but this sounds very much like a small seizure. The safest and wisest thing to do is to take him to the vet to be tested and thoroughly checked out.
A good idea might be to video one of these episodes, which you can then show to your vet. It may give the vet some clues to diagnosis.