The purpose of this study is to test if a nerve block procedure called a stellate ganglion block can help decrease the chance of atrial fibrillation after surgery. Atrial fibrillation is the abnormal, fast beating of the upper chambers of the heart. Stellate ganglion blockade has shown to decrease other types of abnormal heart rhythms as well as decrease the chance of atrial fibrillation.

The investigator hypothesizes that stellate ganglion blockade with local anesthetic performed prior to cardiac surgery will reduce the incidence and duration of postoperative atrial fibrillation (POAF).

Specific Aim 1: Determine the incidence of POAF in patients receiving pre-surgical stellate ganglion blockade with local anesthetic versus saline placebo within one week of surgery or during hospitalization if discharged prior to one week.

Specific Aim 2: Determine the duration of POAF in patients receiving pre-surgical stellate ganglion blockade with local anesthetic versus saline placebo within one week of surgery or during hospitalization if discharged prior to one week.

Specific Aim 3: Determine the success rate of the block as evaluated by ipsilateral hand temperature change and skin sympathetic nerve activity (SKNA).

Inclusion Criteria:

• Patient presenting for cardiac surgery at the Mayo Clinic in Rochester, Minnesota.
• Patients scheduled to undergo mitral or aortic valve surgery with or without coronary artery bypass grafting.

Exclusion Criteria:

• Patients with a history of permanent atrial fibrillation, left or right ventricular assist device implantation or explantation.
• Patients with procedures not requiring cardiopulmonary bypass.
• Patients with procedures requiring deep hypothermic circulatory arrest.
• Patients with active infection or sepsis.
• Pre-operative immunosuppressive medication use (including steroid use).
• Pre-operative anti-arrhythmic medication use (aside from beta-blockers).
• Patients with Immunodeficiency syndrome.
• Patients with known neurologic disorder.
• Patients requiring left internal jugular central line placement.
• Performance of Maze procedures or left atrial appendage ligation procedures will not exclude patients from potential enrollment as atrial fibrillation still occurs postoperatively while the scarring from the Maze procedure forms.