My husband was admitted to the hospital for tests. An employee stated at a meeting he had a heart attack. Not true. Can he sue?

Sue for what? In most cases, in order to sue, you have to prove damage or loss. What damage or loss did you suffer as a result of being told he had a heart attack?

By the way, what did he have?

A couple of things look like possibilities: Defamation (though I don't think it really would fit), Public disclosure of private facts (though they are not correct facts so probably not), If it was done to hurt your husband at work potentially something like intentional interference with business relations.

Though as stated above, you must show damages; loss of job, damage to reputation, injury, etc... None of which I see in your post.

I will say, sue for what,

1. unless they were workers at the doctor or hosptial they are not giving out his medical info, it sounds like they were merely passing on gossip.

2. did saying this harm your husband in any way ?

There is no HIPAA violation or anything else other than the typical rumor mill. No damage has been done by the erreous comment. What makes you jumpt to thinking of sueing over such a comment. You may not like this but your behavior raises more concerns than the employee.