Clinicaltrials.gov is run by the NIH and is a sort of database of studies and trials. I think most have NIH involvement at some level, but not sure about that.
It has a search function. You would expect some studies will be dealing with all the different types of channelopathies: calcium, sodium, potassium, etc, but I did a quick search and did not come up with anything. There were nine channelopathy studies noted, though, so maybe it is covered there.
I would expect Academia to yield some experts; the trick is finding the right individuals at the right institutions - as I am sure you frustratingly know.