After open heart surgery are you able to lay in the tanning bed? if so how long after surgery?

Yes but should not!: Early on the scar may be affected badly and keloid. In general tanning is related to skin cancers of all types. Lying down is not the problem, burning is!, !

Longer is better: Surgical incisions remodel for months. Going to a tanning bed too early risks hyper pigmentation (in addition to the usual tanning risks). Wait at least six months, even longer if possible. As always, tan responsibly!