The combination of propranolol and magnesium does not prevent postoperative atrial fibrillation.
BACKGROUND
Atrial fibrillation is a common complication of cardiovascular surgery. Beta-blockers have been shown to decrease the incidence of postoperative atrial fibrillation. However, the use of magnesium is more controversial. It was our hypothesis that adjunctive magnesium sulfate would improve the efficacy of beta-blockers alone in the prevention of postoperative atrial fibrillation.


METHODS
We prospectively randomized 167 coronary artery bypass patients (mean age 61+/-10 years, 115 men) to receive propranolol alone (20 mg four times daily) or propranolol and magnesium (18 g over 24 hours). Magnesium was begun intraoperatively, and propranolol was started on admission to the intensive care unit.


RESULTS
Using an intention-to-treat analysis, the incidence of postoperative atrial fibrillation was 19.5% in the propranolol-treated patients and 22.4% in propranolol + magnesium-treated patients (p = 0.65). Because combination therapy resulted in an excess of postoperative hypotension, which required withholding doses of propranolol, an on-treatment analysis was also performed. In this analysis, the incidence of atrial fibrillation was still not significantly different (18.5% in propranolol-treated patients and 10.0% in propranolol + magnesium-treated patients, p = 0.20).


CONCLUSIONS
Adjunctive magnesium sulfate, in combination with propranolol, does not decrease the incidence of postoperative atrial fibrillation.
Solomon
A J
AJ
Department of Medicine, Georgetown University Medical Center, Washington, DC 20007, USA. solomona@gunet.georgetown.edu
Berger
A K
AK
Trivedi
K K
KK
Hannan
R L
RL
Katz
N M
NM
D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000517:prevention & control*; D001026:Coronary Artery Bypass; D004359:Drug Therapy, Combination; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000139:chemically induced; D015994:Incidence; D007262:Infusions, Intravenous; D007430:Intraoperative Care; D007902:Length of Stay; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000139:chemically induced / Q000517:prevention & control*; D011433:Propranolol / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011446:Prospective Studies; D016037:Single-Blind Method
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D008278:Magnesium Sulfate; D011433:Propranolol