title: Postoperative atrial tachyarrhythmias in patients undergoing coronary artery bypass graft surgery without cardiopulmonary bypass: a role for intraoperative magnesium supplementation.
abstract: OBJECTIVE
  To determine if intraoperative magnesium supplementation would be associated with a reduction in postoperative atrial tachyarrhythmias (POAT) in patients undergoing coronary artery bypass grafting (CABG) surgery without cardiopulmonary bypass (off-pump CABG surgery).
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  University Medical Center.
  
  
  METHODS
  Patients who had undergone off-pump CABG surgery (n = 124).
  
  
  METHODS
  None.
  
  
  RESULTS
  The charts of 124 patients who had undergone off-pump CABG surgery (64 by anterior thoracotomy and 60 by median sternotomy) were retrospectively reviewed. Demographic data and perioperative care were recorded and compared among patients who did and did not experience POAT and among patients who did and did not receive intraoperative magnesium supplementation. Logistic regression analysis was used to assess the association between magnesium supplementation and incidence of POAT, controlling for other covariables. Of the 124 patients, 16 had a prior history of atrial or ventricular arrhythmias and/or were receiving antiarrhythmic medications. Medical records of the remaining 108 patients were reviewed. Twenty-four patients (22%) had POAT. Forty-two patients (39%) received intraoperative magnesium. In patients receiving intraoperative magnesium, the incidence of POAT was significantly decreased (12% v 29%; p = 0.03). In these patients, initial postoperative serum magnesium was significantly higher (2.37 mEq/L v 1.86 mEq/L; p < 0.01). In patients not receiving intraoperative magnesium, 35% had hypomagnesemia (serum magnesium < 1.8 mEq/L) compared with 9% of patients receiving magnesium (p < 0.01). Patients who received intraoperative magnesium and beta-adrenergic blockers had a lower incidence of POAT (5%) than patients who received only one (19%) or neither (33%) (p < 0.05).
  
  
  CONCLUSIONS
  Intraoperative magnesium supplementation is associated with a decrease in POAT after off-pump CABG surgery. The combination of a beta-blocker and magnesium may reduce POAT further. It is recommended that intraoperative magnesium supplementation be part of the care of patients undergoing off-pump CABG surgery.
authors.affiliation: Department of Anesthesia, Rhode Island Hospital, Providence 02903, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Maslow
authors.forename: M M
authors.initials: MM
authors.lastname: Regan
authors.forename: S
authors.initials: S
authors.lastname: Heindle
authors.forename: P
authors.initials: P
authors.lastname: Panzica
authors.forename: W E
authors.initials: WE
authors.lastname: Cohn
authors.forename: R G
authors.initials: RG
authors.lastname: Johnson
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008274:Magnesium / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control*; D012189:Retrospective Studies; D013610:Tachycardia / Q000517:prevention & control*
chemical_list: D000319:Adrenergic beta-Antagonists; D008274:Magnesium