[1] Wake Forest Sch Med, Dept Anesthesiol, Med Ctr Blvd, Winston Salem, NC 27157 USA
[2] Harvard Med Sch, Dept Anesthesia Crit Care & Pain Med, Massachusetts Gen Hosp, Boston, MA USA
[3] Wake Forest Sch Med, Dept Cardiol, Cardiac Electrophysiol Heart & Vasc Ctr, Winston Salem, NC USA