Metabolic studies following thoracotomy for lung cancer with particular reference to postoperative atrial fibrillation.

Atrial fibrillation has proved to be a frequent complication after thoracotomy for lung cancer. In order to study the possibility that metabolic changes are the trigger mechanism of these arrhythmias, free fatty acids (FFA), glycerol, triglycerides, serum insulin and glucose were determined pre- and postoperatively in patients both with and without this postoperative complication. In the primary series of patients, FFA were found to be increased immediately after the start of the atrial fibrillation, partly in relation to the morning values and partly to the 24-hour curve. This is a possible expression of an increased lipolysis in a causal relationship to the arrhythmia. In another series of patients, the degree of lypolysis was demonstrated using the glycerol values. With this method, no signs of increased lipolysis were found in connection with the onset of atrial fibrillation. Thus, changes in the lipoid metabolism were not found to be the trigger mechanism of the postoperative atrial fibrillation. Reduced values of serum insulin and glucose were not demonstrated either during the uncomplicated postoperative period or at the start of atrial fibrillation.