Yes it was. Until 1992. Albuterol, replaced it.
What brand names was it sold under for human use? I think you are mistaken but by all means show me wrong.
If you have data showing clenbuterol to cause heart enlargement in asthmatics please show me a reference (not animal data). I'm especially interested in evidence that says clen is drastically more cardiotoxic than something like albuterol. Think about this: if clen kills your heart what makes you think albuterol, another beta-2 agonist, doesn't do the same?
The reason clen isn't and wasn't an asthma medication in the US is most likely due to its very long half-life among other things, not because it was found to cause heart enlargement like you claim.
Now go push "chemicals" to little dreamers with a body to destroy.
I'd never recommend clen to anyone or say it's completely safe. But I don't make up "facts" like you.