title: Perioperative metoprolol reduces the frequency of atrial fibrillation after thoracotomy for lung resection.
abstract: OBJECTIVE
  The association of atrial fibrillation with thoracic surgical procedures is well known, but nevertheless its cause is not well defined. Increased sympathetic activity may play a role in the development of atrial fibrillation, and reduced beta-receptor activity may be advantageous. The objective was to evaluate the effect of oral beta-blockade on the frequency of atrial fibrillation and to evaluate some possible causative factors.
  
  
  METHODS
  The study was prospective, randomized, and double-blind, and was conducted at Aarhus University Hospital.
  
  
  METHODS
  Thirty patients without previous or present cardiovascular history undergoing elective thoracotomy for lung resection.
  
  
  METHODS
  The patients received either 100 mg of metoprolol or placebo orally before surgery and once daily postoperatively. Anesthesia consisted of a thoracic epidural block combined with general intravenous anesthesia. Epidural morphine was continued postoperatively.
  
  
  RESULTS
  Patients were monitored with electrocardiograms (ECGs), capillary pulse oximetry, invasive hemodynamic monitoring, central venous oxygen saturation, arterial blood gases, serum electrolytes, and fluid balances. Atrial fibrillation developed in 23.3% of the patients, 6.7% after metoprolol compared with 40% in the placebo group. Atrial fibrillation developed a mean of 2.9 days postoperatively. The predominant hemodynamic findings were perioperative lower oxygen consumption and postoperative lower cardiac index after metoprolol. Patients developing atrial fibrillation had much higher oxygen consumption and postoperative cardiac index than other patients.
  
  
  CONCLUSIONS
  Perioperative oral beta-blockade can reduce the frequency of atrial fibrillation without serious side effects. Increased sympathetic activity is one of the predominant factors in the cause of this complication.
authors.affiliation: Department of Anesthesia, Aarhus University Hospital, Denmark.
authors.forename: C J
authors.initials: CJ
authors.lastname: Jakobsen
authors.forename: S
authors.initials: S
authors.lastname: Bille
authors.forename: P
authors.initials: P
authors.lastname: Ahlburg
authors.forename: L
authors.initials: L
authors.lastname: Rybro
authors.forename: K
authors.initials: K
authors.lastname: Hjortholm
authors.forename: E B
authors.initials: EB
authors.lastname: Andresen
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D011013:Pneumonectomy / Q000009:adverse effects*; D011183:Postoperative Complications / Q000517:prevention & control; D011446:Prospective Studies; D013908:Thoracotomy / Q000009:adverse effects*
chemical_list: D000319:Adrenergic beta-Antagonists; D008790:Metoprolol