PERIOPERATIVE METOPROLOL REDUCES THE FREQUENCY OF ATRIAL-FIBRILLATIONAFTER THORACOTOMY FOR LUNG RESECTION

Objective: The association of atrial fibrillation with thoracic surgic al procedures is well known, but nevertheless its cause is not well de fined. Increased sympathetic activity may play a role in the developme nt of atrial fibrillation, and reduced beta-receptor activity may be a dvantageous. The objective was to evaluate the effect of oral beta-blo ckade on the frequency of atrial fibrillation and to evaluate some pos sible causative factors. Design and Setting: The study was prospective , randomized, and double-blind, and was conducted at Aarhus University Hospital. Participants: Thirty patients without previous or present c ardiovascular history undergoing elective thoracotomy for lung resecti on. Interventions: The patients received either 100 mg of metoprolol o r placebo orally before surgery and once daily postoperatively, Anesth esia consisted of a thoracic epidural block combined with general intr avenous anesthesia. Epidural morphine was continued postoperatively. M easurements and Main Results: Patients were monitored with electrocard iograms (ECGs), capillary pulse oximetry, invasive hemodynamic monitor ing, central Venous oxygen saturation, arterial blood gases, serum ele ctrolytes, and fluid balances. Atrial fibrillation developed in 23.3% of the patients, 6.7% after metoprolol compared with 40% in the placeb o group, Atrial fibrillation developed a mean of 2.9 days postoperativ ely. The predominant hemodynamic findings were perioperative lower oxy gen consumption and postoperative lower cardiac index after metoprolol . Patients developing atrial fibrillation had much higher oxygen consu mption and postoperative cardiac index than other patients. Conclusion : Perioperative oral beta-blockade can reduce the frequency of atrial fibrillation without serious side effects. Increased sympathetic activ ity is one of the predominant factors in the cause of this complicatio n. Copyrights (C) 1997 by W.B. Saunders Company.