Study to Evaluate the Effectiveness of SGB in Preventing Post-op Atrial Fibrillation

Atrial fibrillation requires both an initiation trigger and favorable environment for maintenance and the sympathetic and parasympathetic nervous systems play important roles in this regard. Unfortunately, the precise mechanisms of post operative atrial fibrillation (POAF) are still being investigated. This postoperative complication has persisted in spite of efforts to mitigate it pharmacologically with beta blockers and amiodarone, an experience shared by most other cardiac surgery centers. The stellate ganglion is formed by the fusion of the inferior cervical sympathetic ganglion and first thoracic sympathetic ganglion. By modulating the sympathetic component of the autonomic nervous system, stellate ganglion stimulation has been shown to facilitate induction of atrial fibrillation while ablation may reduce or prevent episodes. Human studies have further supported this model. Preliminary studies of perioperative stellate ganglion block (SGB) in cardiac surgery suggest that this technique may reduce or prevent episodes of POAF requiring treatment. The investigator's hypothesis is that SGB reduces the incidence of POAF in cardiac surgery populations.