We have an employee who had a heart attack last weekend.  He has said the doctor told him he could return to work next Monday.  What requirements/policies do you have in place for 'return to work'?  Do you require documentation from the doctor that it's okay?  I know there are some legal implications in this situation, but to this point we've not experienced this with our company.  Any input is appreciated.

You asked about requirements/policies.  Does your company have any policies on absenteeism/attendance?  Are your return-to-work policies outlined in a handbook and signed by your employee?  Is your company large enough to offer FMLA?

I ask these questions  

I do not know the state level sensitivities on this issue. I have had an attorney reviewed policy in the 5th and 8th circuits saying that if you miss work for any sort of unplanned health care, then you must have a return to work authorization from a health care provider before returning to work.  The point was to reduce potential for WC claims from employees returning to work prematurely and reduce potential for the spread of disease from employees returning to work before they were no longer contagious.  People need to earn their money and I'm sympathetic to that but the policy was created to protect the Company and other employees' health.

EDIT: definitely be sure you are sensitive to the potential FMLA/ADA issues here.