My vet just called with Chum's test results. It's just his thyroid! Not just, it's still serious, but it can be treated and will not affect Chum's lifespan. He's seriously hypothyroid, to the point he has almost no thyroid function at all! My vet said she's never seen it before, but all the research she can find says sudden collapse during exercise can be a symptom of hypothyroidism! He is anemic which again is a symptom of hypothyroidism, apparently a very common one. The cardiologist is not concerned with his heart. He said the resting ECG looks quite normal and the one after exercise has a minor abnormality, but that too is likely stemming from the thyroid. That little gland sure can affect alot of stuff!

I have two other dogs with hypothyroidism. It's fairly common in huskies. So I already have the meds at home. Chum starts .6mg of Thyroxin twice a day as of tonight. In a month my vet wants to redo the tests. Until then, no harness work, but he can go for walks if he feels up to it. If his tests are normal next time, he can go back to pulling, if he wants. Chum was never a really good sled dog and I don't care if he never wants to pull again, but maybe he's been hiding the thyroid problems. Maybe once he feels better those occasional flashes of brillance he has in harness will be more consistent!

I am so relieved. Not sure if I feel like doing a happy dance or crying! Maybe some combination of the two! Thank you all for your kind words and support!