What are my rights if I’m fired for leaving to have open heart surgery?

Generally, an employee could apply for protection under the Family Medical Leave Act.  This requires an employer to hold an employee's job while they are out taking care of serious medical issues like heart surgery or giving birth.  However, only certain employees and employers qualify.  First and foremost, an employee has to have worked for the company for 12 months or worked at least 1250 hours over the last 12 months.  If you have put in a ton of overtime since you were hired, you may qualify.  If you don't, then you cannot avail yourself of FMLA protection.  This means that the employer doesn't even have to offer you the 10 hour part-time position.  However, some employers do have policies which act like FMLA.  Read your hand-books and policies for taking leaves of absence to see if you can invoke one of those provisions to help with you situation.   Depending on how long you have had this condition and how much it has affected your work duties, you may be able to apply for ADA protection.  This ADA protection tends to be very fact specific and more for long-term disabilities, rather than general medical conditions.  However, considering how hard jobs are to obtain in this economy, you may want to consider arranging for at least a consultation with an employment law attorney to review the specifics of your condition to see if you qualify for ADA protection.